Part II: Structures of Things in General

Part II: Structures of Things in General

Part II Structures of Things in General Passage 2 Being, Unity, Goodness, Truth Source: Thomas's public disputations on Truth, 1.1—3, 21.1. Text from Quaestiones Disputatae de Veritate (Opera Omnia, Leonine edn., vol. xxii).

Date: 1257-8, first stay in Paris, aged 32—3.

Type of passage and how to read: Disputed question (see Introduction).

[Question 1] The subject for debate is Truth.

[Article 1] And in the first place we are asked: What is truth?

Being true it seems is just the same as existing:

For [1] Augustine1 says the true is what is, but what is is what exists. Being true then is just the same as existing.

But it was said [by the respondent] that though they refer to the same thing they don't have the same meaning.

Against that: [2] what something means is expressed in its definition; now Augustine settled on what is as a definition of the true, after rejecting several other definitions. If then what is true and what exists are both definable as what is, they seem to have the same meaning...

Moreover, [6] things that aren't the same must differ in some way. But there is no way what is true differs from what exists: not in substance because what exists is in substance true, and not by added differentiations for then there would have to be some genus both share. So they are just the same.

Again, [7] if they weren't just the same, being true would have to add some further condition to existing; but being

Structures of Things in General true is broader than existing, not narrower. Aristotle2 shows this when he says we define truth as saying what is is and what is not is not, thus including in the true both what is and what isn't. Being true then adds no new condition to existing, and it seems the two are precisely the same.

But against that:

[1] useless repetition is tautologically trivial. So if being true and existing were the same, saying that what exists is true would be tautologically trivial, which it isn't. So they are not the same.

Again, [2] existing and being good are interchangeable, but being true and being good aren't: for example, that someone has unmarried sex may be true but not good. So being true isn't interchangeable with existing either, and they are not the same.

Moreover, [3] Boethius3 says that in any creature that it is differs from what is. Now by things being true we mean that they are. So, in creatures, being true differs from what is. But what is is what exists; so in creatures being true differs from existing...

In reply:

In defining what things are, just as in proving things, we must be led back eventually to intellectually self-evident starting-points; otherwise both processes would go on for ever, spelling death to all science and all knowledge. Now

Ibn Slná4 says our first mental conception—the most known as it were to which analysis of all our conceptions leads us—is what exists. Consequently, every other mental con ception adds something to what exists. But to what exists you can't add anything from outside as it were, in the way specifying differentiations are added to a genus, or superven ing properties to a substance, since any sort of nature already is by its nature something that exists (and this is how Aristotle proves5 that what exists names no genus). So adding some thing to what exists means expressing some way in which

Being, Unity, Goodness, Truth

what exists exists not expressed in the word existing, and there are two ways in which this can happen.

Firstly, the way expressed can be a special way of existing.

For existing can have different levels which correspond to different ways of existing and define different categories of thing. Thus, a substance is not some sort of generic existent differentiated by adding a certain nature, but the word substance expresses a certain special way of existing— namely, existing on its own; and other genuses likewise.

Secondly, the way expressed can be a general way attach ing to everything that exists, either in itself or as related to another. In the first case the way can express something positive or something negative. The only non-relative posi tive thing found in every existent is its nature, which deter mines what we say exists, and as having a nature we call anything that exists a thing; for Ibn Síná6 distinguishes being and thing by saying that being derives from the act of existing but the word thing expresses a being's whatness or essence. The non-relative negation that attaches to every existent thing is its non-dividedness, expressed in the word one, for to be one is to exist undivided [as an individual].7

Again if we take the second case, in which a way of existing attaches to each existent thing as related to another, there are two possibilities. One possibility is that the way of existing attaches to an existent thing as divided off from others, and that is expressed by the word something, in Latin aliquid, which is short for aliud quid, a some-or-other thing

(so that just as things existing undivided in themselves are called one, so as existing divided off from others they are called something-or-other). The second possibility arises because of the ways one existent thing can agree with another, and depends on finding something with which every thing can agree. Such is the [human] soul, which Aristode8 says is in a way all things. Human souls can both know and desire, and to express the way in which what exists is agree able to desire we call it good (for as Aristotle9 says every thing desires the good), and to express the way in which what exists is agreeable to mind we call it true.

Now all knowledge is achieved by way of some assimila-

Structures of Things in General tion of the knower to the thing known, an assimilation which causes the knowledge: thus sight is aware of colour because it suffers modification by the kind of the colour. So the first way in which what exists relates to mind under standing it is by harmonizing with it— a harmonizing we call the matching of understanding and thing— and it is in this matching that the formal notion of truth is achieved. So this is what being true adds to existing, namely, the conformity or match of thing and understanding, from which knowledge of the thing follows, as we have said. So that the existence of things precedes their being true, but knowledge follows on as a certain effect of their being true.

This allows us to define truth or being true in three ways.

Firstly, by referring to that which precedes the notion of truth but provides being true with its basis: and this is the way Augustine10 defined the true as what is; Ibn Síná,11 the truth of a thing as the possession of the existence established for it; and someone else, being true as the undividedness of existence and what is. In a second way we define it by referring to that in which the notion of the true is formally achieved: and in this way truth was defined by Isaac12 as the matching of thing and understanding; and by Anselm13 as rightness that only the mind perceives— rightness here expressing a sort of matching; and Aristotle14 said that we define the true as saying what is is and what is not is not. In yet a third way we define being true by referring to the effect that follows on from it: and in this way Hilary15 defined the true as revealing and making clear what exists; and Augustine,16 truth first as that which shows what exists and again17 as that which we judge lesser things by.

Hence: to 1: This definition of Augustine's defines truth by referring to its basis in things rather than to the matching of thing to understanding in which the notion of truth is realized. Or one might answer that when Augustine says the true is what is the word is here is not to be taken to mean the act of existing, but to be a sign of the mind constructing and asserting a proposition: so that it means something is true

Being, Unity, Goodness, Truth

when it is, i.e. when we say of something that is that it is. So that Augustine's definition comes down to Aristotle's one previously quoted. And this gives us the answer to 2 ... to 6: Being true differs in meaning from existing because there is something in its definition which is not in the defini tion of existing; but 'there is nothing in the definition of existing which isn't in the definition of being true. So they are distinguished neither in substance nor by any opposing differentiations. to 7: Being true isn't broader than existing: for in a certain sense existing also applies to non-existents when non existence is apprehended by mind. Thus Aristotle18 says that there is a sense in which absence or lack of being can be said to exist, and Ibn Síná19 too says you can't form a proposition about anything unless it exists, since what you are form ing the proposition about must exist in mind. Clearly then whatever is true exists in a sense.

As to the arguments against that: to 1: Saying that what exists is true is not tautologically trivial; not because the words true and existent refer to different things, but because one of them expresses some thing that the other doesn't. to 2: Although having unmarried sex is an evil, yet as exist ing it can agree with an understanding of it, and in that way realize the notion of being true; so that being true is neither narrower nor broader than existing. to 3: Saying that it is differs from what is distinguishes the act of existing from what is able to exist. Now the word existent derives from the act of existing, not from what is able to exist; so the argument is invalid...

[Article 2] And in the second place we are asked: Is truth primarily something in the mind or something in things?

And it seems In things:

For [1] being true, we said, is interchangeable with existing.

Now things first exist in themselves and then in mind. So the same must hold of their being true...

Structures of Things in General Moreover, [3] whatever exists in something is determined by it. If then truth exists primarily in mind, our judgements of truth will be determined by how mind sees things and we will resurrect the mistake of those earliest philosophers who said that every opinion is true and contradictories can be true together, all of which is absurd...

But against that:

[1] We have Aristotle:20 Truth and falsehood are in the mind, not in things.

Moreover, [2] truth is a matching of thing and mind-, but such matching can only exist in the mind. So truth too can only exist in mind.

In reply:

When a word has a hierarchy of applications, what it first applies to is not necessarily the cause of everything else to which it applies, but is something in which the word's mean ing is first realized to the full. Thus, healthy applies first to animals, for there the full meaning of health is first realized, even though medicine is called healthy as causing that health.

So, since being true has a hierarchy of applications, what it first applies to is the thing in which the meaning of truth is first fully realized. Now the full realization of any change or activity occurs at its end. And the activity of knowing ends up in the mind— for the known must be taken into the knower in the knower's mode— whereas the activity of desir ing ends up in things. That is why Aristotle21 says our mental activities describe a sort of circle: something existing externally moves our mind, as existing in our mind it moves our desire, and our desire moves to attain whatever started the movement; and because as we said, good expresses the way everything that exists relates to desire and true the way it relates to mind, Aristotle22 says that good and bad are in things but truth and falsehood in the mind. Things, however, are called true only in so far as they match up to mind, so that truth exists first in mind and only later in things.

But now note that things relate in one way to practical understanding [that direas behaviour] and in another to

Being, Unity, Goodness, Truth

theoretical understanding [that pursues truth]. Practical understanding causes things and is the measure of what it makes; but theoretical understanding acquires knowledge from things, being changed by them in a certain sense, so that things are the measure of it. So clearly the things of nature, from which our mind draw its science, are the measure of the human mind, as Aristotle23 says, but are themselves measured by God's mind, in which everything exists in the way a craftsman's handiwork exists in a crafts man's mind. God's mind then measures but is not itself measured, things in nature measure and are measured, and human minds are measured and measure not the things of nature but only things artificially made. The things of nature then exist between God's mind and ours and can be called true by matching either. What matches God's mind is called true in the sense of fulfilling what God's mind has laid down, as we see in the definitions of Anselm24 and Augustine25 and in the one quoted from Ibn Slná:26 the truth of a thing is the possession of the existence established for it. What matches

[human] minds is called true if it is intrinsically likely to cause true judgements, in contrast to things we call deceiving because, as Aristotle27 says, they are designed to seem some thing other than they are. Since a thing's relationship to God's mind precedes its relationship to human minds, its truth in the first sense precedes its truth in the second; so, if human minds did not exist, things would still be called true in relation to God's mind, but if we were to think away both minds leaving things by themselves— an impossibility—truth would no longer mean anything.

Hence: to 1: The foregoing shows that what is true is first true understanding and then the thing that matches it. In both senses what is true is interchangeable with what exists, but differently. When said of things what is true is interchange able with what exists as subject and predicate: for every thing that exists matches God's understanding, and is able to match human understanding to itself, and vice versa. But when said of understanding what is true is interchange-

Structures of Things in General able with what exists outside the mind not as subject and predicate, but as condition and consequence, in that to every true understanding there must correspond something that exists, and vice versa... to 3: The attributes of something are determined by it only when caused by it: light in the air, for example, because it is caused by the external sun, follows the sun's movements rather than those of air. In the same way truth in the mind, because caused by things, isn't determined by how the mind sees things but by how things are: for statements— and the understanding they embody—are called true or false inasmuch as things are or are not s o ...

[Article 3] And in the third place we are asked: Does truth exist only in a mind making propositional connections and disconnections?

And it seems not:

[1] For the true is what exists, seen as related to mind.

But mind first relates to things when it conceives definitions articulating what things are. So truth is first found in minds doing this.

Moreover, [2] being true is a matching of things and under standing. But understanding matches things just as much when understanding what things are as when making propositional connections and disconnections. So truth doesn't exist only in minds making connections and disconnections.

But against that:

[1] Aristotle28 says that truth and falsehood exist not in things but in mind; and where simple understanding of what things are is concerned, not even in mind.

Moreover, [2] he says,29 understanding simples occurs where there is no truth and falsehood.

In reply:

Just as it is first understanding that is true and then things, so also it is first understanding as making connections and dis connections and then understanding as articulating what things are. For the meaning of true consists in a matching of

Being, Unity, Goodness, Truth

thing and understanding, and matching presupposes diversity, not identity. So the notion of truth is first found in under standing when understanding first starts to have something of its own which the external thing doesn't have, yet which corresponds to the thing and can be expected to match it. Now when articulating what things are, understanding possesses only a likeness of the external thing, just as the senses do when they take in the appearance of what they sense. But when understanding starts to make judgements about the thing it has taken in, then those are the under standing's own judgements not found in the thing outside, yet called true judgements in so far as they match what is outside. Now understanding makes judgements about the thing it takes in when it says something about how it is or is not, and that we call understanding making connections and disconnections. Thus Aristotle also says30 that connections and disconnections are in mind, not in things. So that is why truth is found first in understanding making connections and disconnections.

But as a consequence, in minds articulating definitions of what things are we find truth in a secondary sense. Thus definitions are called true or false because of some true or false connection [they imply]; the application of a definition to something it doesn't define, the definition of a circle, say, to a triangle; or putting together parts of a definition that can't be connected: defining something as a non-sensing animal, for example, where the implied connection—that some animal is non-sensing— is false. Definitions then can only be called true or false by reference to some connection, just as things can only be called true by reference to mind.

Clearly then being true applies first to the connections and disconnections made in understanding, secondarily to defini tions of things that imply true or false connections, thirdly to things as matching God's understanding or able to match human understanding, and fourthly to human beings choos ing truth, or giving a true or false impression of them selves or others by what they say or do. And words can be called true in just the same senses as the understandings they express.

Structures of Things in General

Hence: to 1: Although mind starts by articulating what things are, that doesn't give mind anything of its own to match against things; so truth in the strict sense isn't found there. And that gives us the answer to 2 . . .

[Question 21] The subject for debate is Goodness.

[Article 1] And in the first place we are asked: Does being good add anything to existing?

And it seems it does:

[1] for things exist by nature, but creatures aren't good by nature but by participating [God's goodness]. So being good adds something real to existing...

Moreover, [4] as one can gather from pseudo-Dionysius,31 good radiates itself and existence. So what makes a thing good is what makes it radiate. Now radiating is a kind of activity, and substances act by way of powers; so things are called good because of something added to their substance.

Being good then adds something real to existing...

Moreover, [10] relationships are differentiated in kind by the term they relate to. Now being good relates to a determinate term, namely, that of goal; so being good is a particular kind of relationship. But any particular kind of existing adds something real to existing in general; so being good adds something real to existing.

Moreover, [11] being good and existing are interchangeable in the way being a human being and having a sense of the ridiculous are. Now despite the interchangeability, a sense of the ridiculous still adds something real to a human being, a property characteristic of human beings but supervening on what defines them. So being good adds something real to existing.

But against that:

[1] Augustine32 says that we exist because God is good, and because we exist we are good. So it seems being good doesn't add anything to existing.

Being, Unity, Goodness, Truth

Moreover, [2] whenever one thing adds to another, really or notionally, one can be understood without the other. But you can't understand things existing without being good.

So being good doesn't add anything to existing, really or notionally. To prove the link-proposition: though God can make more things than human beings can understand, he can't make something exist without it being good, because its very deriving from a good is good, as Boethius points out in De Hebdomadibus. And if he can't make it, neither can we understand it.

In reply:

One thing can be added to another in three ways.

Firstly, what is added can be extraneous to what it's added to, as white adds to body by being something extraneous to what body is.

In a second way, what is added can narrow or further delimit what it's added to, as being human adds to being animal, not because anything in humans is entirely extra neous to animal nature (for that would mean human beings aren't totally animals but only have an animal part), but because the notion of being human narrows down that of being animal, containing explicitly and actually things that the notion of animal contains only implicitly and as it were potentially (for being human involves a life of reason, whereas being animal involves life without saying explicitly whether that is a life of reason or not). And this narrowing of notion which being human adds to being animal has a basis in reality.

In a third way, what is added is entirely notional, in the sense that the notion of one includes something that isn't in the notion of the other, but of a conceptual rather than real nature, whether it narrows the notion it is added to or not.

For being blind adds something— namely, blindness— to being human, but blindness exists not as a real entity but as an entity conceived by reason as a way of apprehending a lack. Being blind said of humans narrows what it's added to, since not all humans are blind, but said of moles it adds without narrowing.

Structures of Things in General Now in the first sense of add nothing can add to existing in general though one can add to particular forms of exist ing; for nothing in nature is extraneous to what constitutes existing in general though things can be extraneous to this or that existent thing. But in the second sense we can add to existing, since existing can be narrowed into ten genuses or categories, in each of which something is added to existing: not, it is true, any property or differentiation extraneous to what existing is, but a determinate way of existing with a basis in real existence. Being good, however, doesn't add to existing in this way since being good is divided among the ten genuses in the same way as existing, as Aristotle33 shows.

So being good either adds nothing to existing or adds something entirely notional, for adding something real would narrow existing into some special genus. But because, as Ibn

Síná says, existing is the first notion mind conceives, all other words must either be synonymous with existing (which can't be said of being good, since it is not tautologically trivial to call what exists good) or at least add something notional. So because being good doesn't narrow existing it must add to it something entirely notional.

But only two kinds of entirely notional additions are possible: negations or relations; for all positive non-relative notions signify things existing in nature. So then, to exist ing as first conceived by mind, being one adds an entirely notional negative (for being one means existing undivided), whilst being true and being good mean something positive and so all they can add is some entirely notional relationship.

Now, according to Aristotle,34 a purely notional relationship is one relating A to B when A does not depend on B but B on A,35 for relation as such is a sort of dependence. We see this in the cases of knowing and known, sensing and sensed, for knowing depends on the known and not vice versa; so the relationship of knowing to known is real, but the relation ship of known to knowing entirely notional, the known being said to have that relationship, according to Aristotle, not because it itself relates but because the other relates to it. And the same happens wherever there is a situation of measure and measured or perfecting and perfected. So what

Being, Unity, Goodness, Truth

being true and being a good must add to existing is some relation of perfecting.

Now there are two things to consider in anything that exists: the nature that defines it, and the fact that it exists as something defined by that nature. So anything that exists can perfect in two ways.* Firstly, it can perfect by way of its defining nature, and that is the way it perfects mind, for it doesn't enter mind with the existence it has in nature and yet mind takes in how it is defined. And this is the way of perfecting which being true adds to existing: being true, as Aristotle36 says, is in the mind and everything existing can be called true in so far as it matches or is matchable to mind; and this is why when truth is correctly defined the definition includes a reference to mind. But there is another way in which what exists can perfect something, not merely by way of its defining nature but even with the real existence it has in nature, and this is the way a good perfects; for good is in things, as Aristotle37 says. But in so far as the existence of one being perfects and fulfils another it relates to what it perfects as a goal; and this is why when good is correctly defined the definition includes some reference to its role as goal: thus Aristotle38 says that good is well defined by those who say it is what everything desires. So first and foremost then a good is something that perfects something else by being its goal, though secondarily we call goods things that lead to a goal— namely, useful goods— and things that are natural consequences of a goal; just as we call healthy not only what possesses health but also what produces or preserves or gives an indication of our health.

Hence: to 1: Because existing is something non-relative whereas being good adds the relationship of being a goal, a thing's own nature standing alone unrelated to anything else is enough ground for calling it existent, but not enough for calling it good. For just as in other types of cause the rela tionship of secondary cause depends on that of a primary cause which depends on nothing further, so with goals: secondary goals derive their relationship of goal from some

Structures of Things in General

ultimate goal which has that relationship of itself. This is why God's own nature, everything's ultimate goal, is sufficient ground for calling him good; hut creatures' natures need to participate in God's relationship of goal before they can be called good. And to that extent we can say, in one way of talking, that creatures are not good by nature but by participation, thinking of the nature itself as notionally dif ferent from the relationship to God which gives it its charac ter of goal and to whom it is ordered as to a goal. But in another way of talking we can say creatures are good by nature, inasmuch as their nature can't exist without this relation to God's goodness: Boethius' point in his De

Hebdomadibus... to 4: Although literally radiating seems to imply activity by an agent cause, broadly understood it implies any causal relationship, just as words like influencing, making, etc. do.

So when we say good of its nature radiates, we shouldn't understand this to mean it acts like an agent but rather plays the role of goal, a sort of radiating that doesn't need any intermediate added powers. Being good implies radiating like a goal rather than agent activity because agents as such don't impose standards of perfection on things but simply initiate them, and also because agents radiate to effects merely a likeness of form, whereas goals radiate to things achievement of their whole existence; and that is what the notion of being good consists in... to 10: Although being good refers to a particular kind of relationship, namely, that of goal, the relationship in ques tion can attach to anything that exists, and doesn't posit any further reality in what exists. So the argument doesn't follow. to 11: Although having a sense of the ridiculous is inter changeable with being a human being, it still adds something extraneous to human beings, in the sense of something not included in their definition. But nothing can add to existing in this way as we have said.

As to the arguments against that: to 1: We concede that being good adds nothing real to existing.

Actual and Potential Being to 2: But the second argument argues that it adds nothing notional either, so to this we say: understanding one thing without another has two senses. Firstly, it could mean under standing the statement that one exists without the other, and in this sense if mind can understand one without another

God can make it exist that way: but existing can't be under stood without being good in this sense (mind can't under stand something to have existence yet not be good). But the second sense of understanding one thing without another is that of understanding a definition, in which one thing is understood without reference to another, in the way we understand animality without having to understand humanity and the other species; and this is the way existing can be understood without being good. But it doesn't follow that God can make things exist without being good, since making precisely brings the things into existence.

Passage 3 Actual and Potential Being Source: Thomas's public disputations on the Power of God, 1.1.

Text from Quaestiones Disputatae de Potentia, Marietti edn. (Turin, 1953), with corrections from the Leonine text in preparation.

Date-. 1265-7, in Italy, aged 40.

Type of passage and how to read: Sections extracted from the summing-up (corpus) of a disputed question and from an answer to an objection (see Introduction).

Notes on translation: Power, potential, potency all translate potentia, which I often translate elsewhere as ability, since it derives from the verb posse, to be able. Act, actual, actuality translate actus; action, active, activity translate actio— both words deriving from the verb agere, to do.

... A thing's power or potential is its openness to some act or actuality, either the primary act of having form, or the secondary act of action. The way we commonly understand the word act suggests that originally it meant action— it is well-nigh universally understood in that way— and was later adopted to mean form, because a thing's form of existence

Structures of Things in General determines its activity and goal. So things can have a double potential: an active potential of the act of activity (the original meaning of words like potency and power), and a passive potential of the primary act of form (a derived and secondary meaning of the words).

To be acted on things must have passive potential, and to act they must have the primary act of form. (The word act, as we said, though it first meant being active, has come to mean this primary actuality of having form.) So God, who is pure and primary act, must of all things be the most active spreading his likeness abroad, and so must of all things be the most powerful or actively potential source of activity.

... to 10: There can be something real corresponding to notions in our mind mediately or immediately: immediately when what mind conceives is the form of something exist ing outside the mind, of a human being, say, or a stone; mediately when the very act of understanding produces something which the mind reflects on, so that something real corresponds to what the mind is reflecting on only mediately, that is, by way of mind's own understanding of what is real.

For example, our mind understands human beings, horses, and many other species all to have the nature of animal, and reflecting on that understands animal to be a genus. Now nothing real outside corresponds immediately to the notion of genus, but to the understanding which gave rise to the notion there does correspond some reality.

The case of the relationship of source which the notion of [God's] power adds to that of [God's] substance is sim ilar: something real corresponds to it, but mediately, not immediately: for our mind understands creatures to have a relationship of dependence on their creator, and for that very reason— since it can't understand a relationship going one way without also understanding it going back the other way— it understands God to have a relationship of source; and this corresponds to reality, but only mediately since it arises from our way of understanding things.

Matter, Form, Agent, Goal

Passage 4 Matter, Form, Agent, and Goal Source: On the Principles of Nature (complete). Text from De

Principiis Naturae (Opera Omnia, Leonine edn., vol. xliii).

Date: Probably from early days in Paris, 1250s, aged about 25.

Type of passage and how to read: A sort of student's vade-mecum, an introduction to causality, heavily dependent on Ibn Rushd's interpretation of Aristotle's teaching in Physics, 1 and 2.

[Matter] [1] Some things are, while some things can be, but aren't. We say that what can be exists potentially, and what already is exists actually. But existence has two senses. The essential existence of things as substances— a human being being a human being, for instance— is existing (period!); but non-essential existence— a human being being white, for instance— is existing in a certain respect.

In both senses things can exist potentially: sperm and menstruae are potentially a human being, and human beings are potentially white. And we can call whatever exists poten tially matter or material—whether its potentiality is to exist as a substance (sperm to be a human being), or to exist in some non-essential respect (human being to be white); though there is this difference: we call material with poten tial to exist as substance material from which, but material with potential to exist non-essentially material in which.

Putting this another way, only what has the potential to exist as a substance is properly called matter or material, and what has the potential of existing in some non-essential way is called, strictly speaking, a subject. An indication that subject means what has the potential of existing in some non-essential way is that we talk of a subject's non-essential properties as inhering in it, but not of its essential form as inhering in it. Matter and subject differ in this way: of itself a subject exists completely, needing nothing more in order to exist (human beings don't depend for existence on being

Structures of Things in General white); but matter exists incompletely of itself, needing something more in order to exist. So, strictly speaking, form gives matter its existence, whereas non-essential properties are given existence by their subject. But sometimes we use these words interchangeably: matter for subject, and subject for matter.

[Form] Now just as anything potential can be called material, so anything that gives existence, be the existence essential or non-essential, can be called form: whiteness makes a potentially white human being actually white, and the soul makes sperm— potentially a human being— into an actual human being. Because forms make things actual, forms are called actualizations or acts: substantial form makes some thing actually exist as a substance, and non-essential forms make it actually exist in various non-essential modes.

And since the change that introduces a form is called being generated, there are two senses of being generated cor responding to the two senses of form: being generated

(period!), corresponding to substantial form, and being generated in a certain respect, corresponding to non-essential forms. Introduction of substantial form we call coming to be

(period!); but introduction of a non-essential form we call coming to be such-and-such, not coming to be (period!): when a human being turns white we don't talk of it coming to be or being made (period!), but coming to be or being made white. And to these two senses of being generated correspond two senses of decomposition: one strict, the other in a certain respect. Being generated and decomposing in the strict sense apply only in the genus of substance, but in the qualified sense they apply also in other genuses of being.

And because being generated moves from not existing to existing (decomposing moving in the opposite direction from existing to not existing), generation starts not from any sort of not existing but from a not existing which is potential of existence: statues are made from copper which is potentially a statue though not actually. So three things are needed for

Matter, Form, Agent, Goal

generation: something potential of existence— the material or matter, its lack of actualization— a lacking of being, and something to give it actualization— a form. When statues are made from copper, copper is the material potential of statueform, its shapelessness or unworked state is the lack, and the shape of the statue is the form. That shape is not a substantial form, since copper already actually exists before it receives shape or form and does not depend for existence on the shape; like all artificial forms, it is a non-essential form, since art or artifice operates on material which already of its nature completely exists. [2] So there are three principles

[or origins] of nature: matter, form, and lack of form; one, namely, form, is where generation is going to, and the other two characterize where generation comes from.

[Lack of form] But matter and lack of form characterize the same subject in different ways: before form arrives the same thing is both bronze and shapeless but bronze for one reason and shape less for another. Lack of form, then, is a principle not in its own right but incidentally, because it coincides with matter; just as doctors build houses only incidentally, since they build them not as doctors but as builders, doctor and builder happening to coincide in one subject.

But even what is incidental can sometimes be necessary and inseparable (as a sense of the ridiculous is to being human), and sometimes unnecessary and separable (as white ness is to being human). And in this way, lack of form, though an incidental principle, is still necessary to genera tion, since the material must lack the form to start with; as existing under one form it lacks another and vice versa, as fire lacks that of air and air that of fire.

Note too that though generation starts out from non existence we don't locate its origin in absence, but in lack; for absence doesn't imply a subject. Even things that don't exist can be said not to see— chimeras don't see, and things like stones too that aren't meant to see. But only things meant to see are called blind: lack implies some type of subject meant to have what is lacking. So because generating

Structures of Things in General doesn't start from non-existence (period!) but from non existence in some subject, and not just any subject but a particular type of subject— you can't generate fire from any non-fire thing but only from a non-fire thing open to being fire— it is lack[, not absence,] of form that we call the prin ciple or origin.

Lack differs, however, from the other origins. The others are principles of being and of coming to be: for a statue to come to be you need bronze and, at the end, shape, two things still needed when you already have the statue; lack, on the other hand, is a principle only of coming to be, not of being: for while coming to be a statue it must be not-statue

(otherwise it couldn't come to be, since only before-and-after things [like time] are their own coming to be); but once the statue exists there is no longer a lack of statue, since lack and having can no more coexist than is and isn't. Another dif ference, as we explained earlier, is that lack is a principle coincidentally, whereas the other two are principles in their own right.

Clearly then matter differs by definition from form and from lack of form, and can be understood as taking on either: copper can be understood to have shape or shapeless ness. And sometimes the material's name implies lack of form and sometimes not: calling a statue's material bronze doesn't imply lack, for the word bronze doesn't imply any unworked or shapeless state; but calling bread's material flour does imply lack of the form of bread, for the word flour implies an unworked and unstructured state opposed to the form of bread. And because, in generation, the subject material persists whilst the lack and the complex of material and lack don't, material implying lack passes away whilst material not implying it persists.

[Ultimate matter] But note that some matter is already formed: bronze, for example, though it is statue-material, is itself formed matter; it contains its own material and so cannot be called ultimate material. Only material subject to form and lack of form but having no particular form or lack of form in itself can be

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called ultimate material [first matter], because it presupposes no other material; and another name for it is yle. But since we define and know things by way of their forms, ultimate matter can't be known or defined as such, but only by an analogy, as that which relates to all forms and lack of forms as bronze does to statues and to shapelessness, and so is ultimate (period!). One might talk of matter ultimate in a particular genus— water, for example, as the ultimate liquid— but that wouldn't be ultimate (period!), for, being itself formed matter, it presupposes some matter.

Note that neither forms nor ultimate matter are generated or decompose, since all generation must start and end some where, starting from matter and ending with form. If matter and form themselves were to be generated, matter would need matter and form form without end. So properly speak ing only things composed of matter and form are generated.

Note also that there is only one ultimate matter underlying everything. But a thing can be one by having a single deter minate form— the way Socrates is one, but not ultimate matter since in itself it is without form— or by having nothing to make it more than one— and this is the way ultimate matter is one, because it is understood without anything that would make it more than one.

And note that although matter in its nature is neither formed nor formless (as bronze in its nature is neither shaped nor shapeless), it never exists stripped of form and lack of form, but sometimes takes on one form and sometimes another. By itself it can never exist for it has no form of its own and so— because actual existence comes with forms— matter by itself never exists actually but only potentially.

Nothing actually existent then can be called ultimate matter.

[Agency] [3] So now we have shown nature to have three principles: matter, form, and lack of form; but these are still not enough for generation to occur. For what potentially exists can't bring itself to actualization: copper is potentially a statue, but can't make itself into a statue: it needs a workman to draw the statue's form out of potentiality into actuality.

Structures of Things in General For the form too can't draw itself out of potentiality into actuality— and I am talking of the form of the thing gener ated, the end-product of generation, as we said— for the form won't exist until the thing is made, whereas the maker exists in the coming to be, that is, while the thing is coming to be. So besides matter and form there must be some active principle or origin, which we call the efficient cause or mover or agent, from which the change originates.

[Goal] And because to be active, as Aristotle1 says, what is acting must tend towards something, there must be yet a fourth thing towards which the agent tends, called the goal. Note that every agent, whether it acts by nature or by will, tends towards a goal, though it doesn't follow that every agent is aware of a goal or deliberates about it. Something that hasn't a fixed way of acting but can go either way— as willing agents can— must consider a goal and use that to decide how to act; but natural agents act in fixed ways and don't need to choose the means to their goals. Ibn Slná2 gives the example of a guitar-player who doesn't have to think about every pluck of the strings because they are now second nature to him; otherwise he would pause between each pluck and ruin the sound. And since [the guitar-player] who acts by will is more likely to deliberate than things that act by nature, we can argue a fortiori that natural agents can tend to goals without deliberating, where tending towards is simply hav ing a natural bias towards something.

[Principles, causes, and elements] So now we see there are four causes: material, efficient, formal, and final. And although Aristotle3 says the words origin and cause are interchangeable, in another place4 he lays down four causes and three origins or principles. The causes he accepts are both intrinsic and extrinsic— matter and form being a thing's intrinsic, constitutive parts, whilst agent and goal are outside the thing and extrinsic; but as principles he accepts only intrinsic causes, and lack of form, which is not accounted a cause because, as we said, it is only

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incidentally a principle. What we call the four causes are causes in their own right to which all incidental causes lead back, since anything coincidental must lead back to some thing essential. And although here Aristotle calls intrinsic causes principles, strictly speaking— as Ibn Rushd5 says elsewhere— principle» are extrinsic causes, elements are intrinsic, constitutive causes, and both are called causes.

But sometimes we use the terms interchangeably, calling all causes principles and all principles causes.

All the same, we seem to mean more by cause than we usually mean by principle or origin, for any beginning, whether followed by existence or not, can be called an origin. Thus we say the knife originated from the smith, meaning he was the source of the knife's existence, but also that a change from black to white originates in blackness (generally calling anything where a change starts its origin) though blackness is not the source of the following whiteness's existence. A beginning is only called a cause, however, if it gives existence to what follows, for a cause, we say, is that from the exis tence of which another follows. So a beginning where a change starts cannot of itself be called its cause, even it is called its origin; and that is the reason lack of form, which is where generation starts, is called an origin but not a cause. Though it can also be called a cause coincidentally, as coinciding with the matter in the sense explained earlier.

Elements, however, are strictly speaking causes which form part of a thing's make-up: material causes, then, strictly speaking, and again not every material cause but those which are part of a thing's ultimate make-up. Thus the elements of a human being are not limbs, since limbs in turn are com posed of other things; but earth and water are called elements because they are not made up of further bodily components, but themselves ultimately make up all natural bodies. So Aristotle6 defines an element as what things are ultimately made up of, existing in the things, and indivisible in its own nature. The first phrase— what things are ultimately made up of—is explained by what we have said. The second— existing in the things— is there to distinguish elements from the sort of matter that disappears during generation. Bread,

Structures of Things in General for example, is material for blood, but to build up the blood you must break down the bread, so that bread doesn't persist in the blood and you can't call it an element of blood.

Elements must persist in some way since, as Aristotle7 says, they can't be broken down. The third phrase— indivisible in its own nature— is there to distinguish elements from things that contain heterogeneous parts differing in nature, like hands made up of flesh and bone (which differ in nature).

Elements, however, don't divide into heterogeneous parts: every bit of water is water. For elements can be quantitatively divided into parts, as long as those parts are homogeneous; though sometimes elements are completely indivisible: letters, for example, are the elements of syllables.

So now we can see how a principle is something wider than a cause, and a cause something wider than an element; as Ibn Rushd says.8

[Mutual relations between causes] [4] Now that we have seen the four classes of cause, note that it is possible for one thing to have many causes (copper and the craftsman both cause the statue, but the craftsman as producer, the copper as material), and for one cause to have opposed effects (a steersman can save or sink a ship by his presence or absence).

Note too that it's possible for one thing to be both cause and effect of another, though in different respects: walking is a productive cause of health, and health is sometimes the goal of walking and its cause in that sense; and body is material for soul, whilst soul is form of body.

Productive causes cause goals inasmuch as what an agent does realizes a goal, and goals cause productive causes inasmuch as the agent can't do anything except by tending towards a goal. So a productive cause causes the thing that is the goal— health, for example— but doesn't cause it to be a goal, doesn't cause the goal-causality of the goal, doesn't give it its goalness. For example, a doctor makes health actually exist, but doesn't give health its drawing power. Goals, on the other hand, don't cause the things that are productive, but do cause their productiveness. Health isn't what makes

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the doctor exist9— I am talking of the health his doctoring produces— but it does cause him to be productive. So the goal is the cause of the producer's causality, the cause of his productiveness. In the same way the goal makes material material and form form, since material only takes on form and form only makes, something out of the material because of the goal. This is why the goal is called the cause of causes: because it causes the causality of all other causes.

Matter causes form inasmuch as forms only exist in matter; and similarly form causes matter inasmuch as matter can only actually exist under a form. As Aristotle10 says, matter and form are correlatives, related as simple parts to the composite whole they together make up.

[Priority among causes] But since causes as such are always prior in nature to what they cause, note that, because of the two senses of prior that Aristotle11 distinguishes, something can be said to be both prior and posterior to one and the same thing, both cause and caused. For prior can mean occurring earlier in the temporal process of generation, or, again, ranking first in completeness of being. Because activity in nature moves from the incomplete and unachieved to completeness and achieve ment, the unachieved is prior to the achieved in the temporal process of generation, though the achieved is prior in com pleteness. So we say adults come before children in complete ness of being, though children come before adults in the temporal process of generation.

But though unachieved potential precedes actual achieve ment in things that are generated— seeing that each such thing is first unachieved then achieved, first potential then actual— nevertheless, simply speaking, achieved actuality comes first, for the actual actualizes the potential and the achieved brings the unachieved to achievement. Matter precedes form in the temporal process of generation, because what takes on is prior to what is taken on; but form precedes matter in achievement, because matter is incomplete without form. In the same way, agent precedes goal in the temporal process of generation, since the agent initiates the movement

Structures of Things in General towards the goal; but goal precedes agent (as agent) in completeness of being, since the agent's activity fulfils itself in the goal. So these two causes— matter and agent— are prior in the temporal process of generation, but form and goal are prior in regard to achievement.

Note too that necessity has two senses: absolute and hypothetical necessity. Absolute necessity results from causes prior in the process of generation: matter and agency; thus, death's necessity arises from matter and the inherent conflict between [its] components. And it is called absolute because nothing can stop it; and we also call it material necessity.

Hypothetical necessity results from causes posterior in the process of generation: form and goal; thus, conception is necessary if a human being is to be born. And it is called hypothetical because it is not necessary (period!) that this woman should conceive, but only on the hypothesis that a human being must be born; and we also call it necessity for a goal.

[Coincidence among causes] Note that three of these causes— form, goal, and agent— can coincide: when fire produces fire, fire is the agent cause (the producer), the form that realizes the potentiality, and the goal that the agent tends towards in which its activity is fulfilled. However, there are two senses of goal: the goal of production and the goal of the product: in the production of knives, for example, the goal of production is the form of a knife, but the goal of the product— the knife— is the knife's own activity— cutting. So the goal of production sometimes coincides with the other two causes: namely, in reproduction of species, human being reproducing human being and olivetree olive-tree; but there can't be coincidence with the goal of the product. Note, moreover, that goal and form can coincide in the same individual, since the goal of production is the individual form produced; but agent can't coincide in the individual but only in species: maker and made can agree in species but can't be the same individual; when human beings produce human beings, one individual pro duces another like to it in species. Matter never coincides

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with other causes since it exists potentially and is by nature unachieved, whereas other causes exist actually and are by nature achieved; the achieved and the unachieved cannot coincide.

[Subdivisions of causes] [5] Note that there are several ways of subdividing each of these four types of cause— agent, material, form, and goal.

For we distinguish primary and secondary causes. Thus the doctor and his skill are both agents of health, but skill is the primary agency and the doctor secondary; and the same distinction can be made in forms and in the other types of cause. Note that we should always press questions back to the primary cause: to the question 'What cured him?' and the answer 'The doctor', we should ask 'How did he do it?' and answer 'By his skill'. Note too that the distinction between proximate and remote causes is the same as this one, the proximate cause being secondary and the remote cause pri mary. And observe that the more general cause is always the more remote, and the more specialized one the more proximate: the proximate form of a human being is what defines him— a mortal animal with reason, his animality being more remote, and his substantiality still more so. For the more general is a form of the less general. In the same way copper is the statue's proximate material, metal is more remote, and body most remote of all.

Again, we distinguish inherent and incidental causes. The inherent cause is the cause of something as such: builders the agents of houses and wood the material of stools. An incidental cause is something coincidental to the inherent cause: a grammarian builder, for example, since a grammarian is an agent of buildings incidentally, not as grammarian but as builder— who happens to be a grammarian. And similarly for other causes.

Again, we distinguish simple and composite causes. A simple cause is a cause mentioned on its own, be it inherent or incidental: the simple agent of the house is the builder, or this doctor. The composite cause is both mentioned together: the agent is this doctor-builder. Or we can adopt Ibn Síná's

Structures of Things in General explanation and say a simple cause is what can cause on its own, as copper without any additional material can make a statue, or doctors cure, or fire heat. But a cause is composite when several things are needed to cause something, as many men are needed to move a ship, and many stones to provide material for a house.

Again, we distinguish actual and potential causes. An actual cause is something actually engaged in causing, as a builder when building and copper when providing material for a statue. A potential cause is able to cause but is not actually engaged in doing so, as a builder when not build ing. Note that where actual causes are concerned cause and caused must exist simultaneously: if one exists so must the other; when a builder is an actual builder actual building must be going on, and vice versa. But this doesn't have to be so for potential causes.

[Generality and particularity applied to causes] Note, however, that we compare general causes with general effects and individual causes with individual effects: builders are the cause of houses, this builder of this house.

[6] Note too that when talking of intrinsic principles like matter and form, whether they are the same or different is determined by whether what they are principles of is the same or different. For certain things are individually the same, like Socrates and this man (pointing at Socrates); others are different individuals of the same species, like

Socrates and Plato, who are both human beings but different individuals; others differ in species but not in genus, like human beings and donkeys, which are both animals; others differ in genus and are only proportionately or analogically the same, like substance and quantity, which are different genuses of being, and the same only by analogy, for they share being, and that is not a genus and is attributed to things not univocally but analogically.

To understand this last point note that what is attributed to a set of things may be attributed univocally, equivocally, or analogically. It is attributed univocally if the same word is used with the same meaning or definition every time it is

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attributed, as when human beings and donkeys are both called animals: the same word animal is used with the same definition: a living thing endowed with sensation. It is attri buted equivocally if the same word is used but with different meanings, as when something which barks and a star in the heavens are both called the dog: the word is the same but its meaning or definition is different (for the meaning of names is their definition, as Aristotle12 says). It is attributed analogically if it is attributed to several things with different meanings but all having reference to some one thing, as when we call organisms and medicines and complexions all healthy: the meaning is not altogether the same, for com plexions are called healthy as indications of health, organisms as subject to it, and medicines as causing it, but all the meanings have reference to the one health that is their goal. Sometimes the reference binding the meanings together analogically (in a proportion or relation or agreement) is to a single goal, as in the example just quoted; sometimes to a single agency, as when skilled doctors and unskilled old women and even their tools are all called healing by reference to the one agency of the healing art; and sometimes to a single subject, as when we call substances, quantities, qualities and all the other [Aristotelian] categories beings, for although quantity and the others are not beings in exactly the same sense as substance is being, still each of the others is called being because of its relation to substance as its subject. So being is attributed first to substance and only secondarily to other attributes, and that means being is not a genus comprising substance and quantity [and the rest]— since genuses are predicated equally of their species— but is attri buted analogically. And that is why we said earlier that substance and quantity are different genuses, the same only by analogy.

So the matter and form of one and the same individual— of Tully and Cicero13— are the same individually; the matter and form of different individuals of the same species— of Socrates and Plato— are the same in species but differ individually; and in the same way the principles of things that are generically the same are themselves generically the

Structures of Things in General

same— the bodies and souls of donkeys and horses differ in species but are the same generically; and in the same way the principles of things that are only analogically the same are themselves only analogically or proportionately the same.

Thus, matter, form, and lack of form, or potentiality and actuality, are the principles of all the categories— substance and the rest— but the matter of substance and of quantity, and their form and lack of form, differ in genus and agree only proportionately: as the matter of substance is material to substance, so also the matter of quantity to quantity.

However, substance is also the cause of the other categories, so that substance's principles are also principles for every other category.

Passage 5 Substance and Accidents, Action and Passion Source-. Thomas's commentary on Aristotle's Physics, 3.3 (202a22202b29). Text from In Aristotelis Libros Physicorum, 3.5 (Opera

Omnia, Leonine edn., vol. ii).

Date: 1268, Italy, aged 43.

Type of passage: Commentary with digression (see Introduction).

How to read: With one finger on the commentary and one on Aristotle's text, which has been inserted, italicized, in short para graphs. Aristotle's text has been translated in such a way that it can be compared on the one hand with modern translations of Aristotle's text, and on the other with the extracts Thomas quotes in his commentary.

After declaring that change is an actualization both of what is causing the change and of what is changed, Aristotle raises a difficulty: and first [at This view has a dialectical defect] he proposes the difficulty, and then, at It is not absurd, he solves it.

[Aristotle's text, 202*22-2 0 2 b4] This view has a dialectical defect. Perhaps agents must be actualized in some way, and patients actualized in some way.

What actualizes an agent is called action, and what actualizes

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a patient passion: the activity and goal of agents is action, and of patients passion. Since then they are both changes, if different they must be in a subject: either both in the patient undergoing change, or action in the agent and passion in the patient. If someone were to call this latter action he would be equivocating. Now in the latter case there will be change in what causes change. For the same argument must hold for what causes change and what undergoes change, so either everything causing change will change, or something in which there is change will not change. If on the other hand both are in the patient undergoing change, both action and passion, and teaching and being taught though they are two are in the learner, then first a thing's actualization will not exist in it, and then a second absurdity: one same thing will undergo two changes like one subject undergoing two modifications towards one form, which is impossible. Is the actualization one? Someone could say it is absurd that one and the same thing would actualize two things which are different in kind. Then action will be identified with passion and teaching with learning, to act will be the same as to undergo and to teach the same as to learn, all teachers will be learning and all agents undergoing.

[A difficulty] And in proposing the difficulty, first he prefaces the difficulty with a preliminary remark, and then, at Since then they are both, expounds the difficulty. He starts by saying that This view has a dialectical defect, i.e. a logical difficulty, since there are plausible reasons for and against it. And he makes a preliminary remark, saying that agents [of change] are actualized in some way, and patients [of change] actualized in some way (which parallels what he said earlier: that both what causes change and what undergoes change are actualized in some way). What actualizes an agent is called action, and what actualizes a patient passion. This he proves: since what actualizes and achieves things is their activity and goals, and since, self-evidently, the activity and goal of agents is action, and of patients passion, it follows that action actualizes agents and passion patients, as he has said.

Next, when he says Since then they are both, he expounds

Structures of Things in General the difficulty. Clearly both action and passion are changes, for both are identified with change. So action and passion are either the same change or different changes. If different each must exist in a subject: either both in the patient undergoing change, or one of them (namely, action) in the agent, and the other (namely, passion) in the patient. If someone were to say the opposite— that passion is in the agent and action in the patient— clearly he would be equivocating, simply calling passion action and vice versa. A fourth alternative seems to be overlooked: namely, that both are in the agent; but he passes this over because he has shown change to take place in what is changed, which excludes this alternative of neither being in the patient and both in the agent.

Of the two alternatives mentioned he first pursues the second, saying Now in the latter case. For since as we have said action is a kind of change, if someone says action is in the agent and passion in the patient, there will be change in what causes change. For the same argument must hold for what causes change and for what undergoes change, namely, that everything in which there is change must change. (Or, the same argument must hold for what causes change and what undergoes change as holds for patient and agent.) Any thing in which there is change, then, must change; so it follows either that everything causing change will change, or that something in which there is change will not change; both of which seem absurd.

Next, when he says If on the other hand, he pursues the first alternative. If someone says both action and passion, though they are two changes, are in the patient undergoing change, and that teaching (the teacher's side of things) and being taught (the learner's side) are both in the learner, there are two absurd consequences. The first [a] comes from our having said that action actualizes the agent. If then action is in the patient, not the agent, it will follow that a thing's own actualization will not exist in it, the thing that it actualizes.

And then there will follow a second absurdity: namely, that one and the same thing will be undergoing two changes. For at the moment we are supposing action and passion to be two changes. Now whatever change exists in will be changed

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by that change. So if what can change has both action and passion in it, it will follow that what can change will be changed by two changes. This would be like one and the same subject undergoing two modifications towards one and the same form— one subject turning white twice at once— which is impossible. There's no absurdity about one subject undergoing two modifications at once towards different forms— turning white and turning hot, for instance. But action and passion clearly tend towards the same form, since what the agent does is what the patient undergoes.

Next, when he says Is the actualization one?, he goes back to the beginning of the difficulty. Someone could say that action and passion are not two changes but one; but this has four absurd consequences. First [b], one and the same thing would actualize two things which are different in kind. For action has been said to actualize the agent and passion the patient, and these differ in kind. If then action and passion are one change, that change must actualize two things dif ferent in kind. The second absurdity that follows if action and passion are one change is [c] that action will be identified with passion and teaching (the teacher's part) with learning

(the learner's part). The third absurdity is [d] that to act will be the same as to undergo and to teach the same as to learn.

And the fourth consequence is [e] that all teachers will be learning and all agents undergoing.

[Aristotle's text continued, 202b5—22] It is not absurd that the actualization of one thing should exist in another, for even if teaching actualizes the teacher, it tends into another thing without break; it belongs to this thing yet exists in that. Nor is there anything to prevent something that actualizes one thing from actualizing another, as long as it differs in being, like what exists potentially to an agent. Nor is it necessary for all teachers to be learning even if to act and to undergo are one and the same: provided they're not the same by definition, as raiment and dress are, but as the road from Thebes to Athens and the road from Athens to Thebes are the same, as was said earlier. For things which are the same in a certain respect don't have to be

Structures of Things in General

altogether the same, but only if they are the same by defini tion. Nor even if teaching was identified with learning would to teach be to learn; just as when one distance separates two things this's distance from that and that's from this are not one and the same thing. Altogether it should be said that it doesn't follow that action and passion are the same, or teaching and learning, but only that the change they pre suppose is one and the same change; for it is defined in one way as the actualization of this thing received in that, and in another as the actualization of that thing issuing from this.

[Aristotle's solution of the difficulty] Next, when he says It is not absurd, he solves the preceding difficulty. For from what we have said it is already clear that action and passion are not two changes but one and the same change, called action in so far as it is caused by an agent, and passion in so far as it takes place in a patient. So we don't need to solve the absurdities that follow from suppos ing action and passion to be two changes, except for one absurdity [a] that needs solution even if action and passion are one and the same change: for since action is an actualiza tion of an agent as we have said above, if action and passion are one and the same change, it follows that what actualizes the agent is somehow in the patient, and that means what actualizes one thing exists in another. But there were four absurdities consequent on the other supposition; so five await solution.

So first he says that It is not absurd [a] that the actualiza tion of one thing should exist in another, for even if teaching actualizes the teacher, it is something coming from him and tending into another thing without break or interruption; so that the same actualization belongs to this thing, namely, the agent, as that from which it comes, and yet exists in the patient, as that in which it is received. This would only be absurd if what actualized one thing were to exist in the other in exactly the same way in which it actualized the first thing.

Next, when he says Nor is there anything to prevent, he solves another absurdity, namely [b], that one and the same thing would be actualizing two different things. Nor, he says,

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is there anything to prevent something that actualizes one thing from actualizing another, as long as, however one it is in reality, it differs in some aspect of its being, just as it was earlier said that one and the same interval relates two to one and one to two, and what exists potentially to an agent and vice versa. One and the same actualization in reality relates to each of the two in a different respect: to the agent as coming from it, and to the patient as existing in it.

To the remaining three absurdities, which are deduced one from another, he responds in reverse order. Firstly, to the one he mentioned last, as the most absurd. So his third response is to the fifth absurdity [e]. Nor, he says, is it necessary for all teachers to be learning or all agents under going even if to act and to undergo are one and the same: provided we're not saying they're the same by definition, as raiment and dress are, but only that they're the same in subject and differ in definition, as the road from Thebes to Athens is the same as the road from Athens to Thebes, something he said earlier. For things which are the same in a certain respect don't have to be altogether the same, but only if they are the same both in subject (or in reality) and by definition. So, even were we to suppose that acting and undergoing were the same thing, because, as we have said, they would not be defined the same way, it wouldn't follow that whatever is acting must also be undergoing.

Next, when he says Nor even if teaching, he replies to the fourth absurdity [dj. And he says that it wouldn't follow, even if teaching was identified with learning, that to teach would be to learn, since teaching and learning are abstract concepts, but to teach and to learn concrete actions. That means they are pursuing goals and ends and as such receiving the different definitions of action and passion. Just as we talk of one distance separating two things abstractly considered, though if we orient it towards one end or the other, calling it this's distance from that and that's from this, these are not one and the same thing.

Next, when he says Altogether it should be said, he replies to the third absurdity [c], demolishing the argument that if action and passion are one and the same change then action

Structures of Things in General

and passion are one and the same. And he says that in the final analysis it should be said that it doesn't follow that action and passion are the same, or teaching and learning, but only that the change they presuppose is one and the same change. This change is defined in one way as action and in another as passion. For it is defined in one way as the actualization of this thing received in that, and in another as the actualization of that thing issuing from this. Change is called action inasmuch as it actualizes an agent by being from it; and it is called passion inasmuch as it actualizes a patient by being in it.

Thus it is clear that change, belonging both to what causes the change and to what is changed by it, is still one thing which abstracts from these different respects, whereas action and passion differ because they include these different respects in their meaning.

[Further difficulties: a digression by Thomas] The above shows that change, since it abstracts from what defines action and passion, cannot belong in either the [Aristotelian] category of action or in that of passion, as certain people have asserted. However, two difficulties remain about this. Firstly, if as we have said action and passion are one and the same change and differ only in the way the change is defined, then it seems they shouldn't name two categories, since categories are classes of things. Again, if change is either action or passion then how can there be change in [the other categories of] substance, quality, quantity, or place, as we have said there are? Surely there can only be change in action and passion?

[Preliminary discussion by Thomas of the Aristotelian categories] For clarity on these matters note that being is divided [by Aristotle] into ten categories not as a genus is divided into species, univocally [as though being had one meaning], but according to different senses of being. These senses of being correspond to the ways in which something can be said to be something. When we say: This is thus, we ascribe [predicate]

Substance, Accidents, Action, Passion

one thing to another; and so the ten genuses of being are called ten ascription-categories [predicaments].

Now there are three ways of ascribing. Firstly, we can ascribe to a subject something that is of its essence, as when we say: Socrates is a human being, or: A human being is an animal; and this is tjie category that ascribes substance.

Secondly, we can ascribe to a subject something not of its essence, but nevertheless existing within it. And that will either be something consequent on the subject's material— the category that ascribes quantity, for quantity is a charac teristic consequence of materialness: thus Plato saw bigness as something material— or something consequent on the subject's form— the category that ascribes quality, so that qualities presuppose quantity, like colours a surface and shapes lines and surfaces— or something relating the subject to other things— the category that ascribes relationship, for when I call this human being a father I ascribe to him not something he has as standing alone, but something which though intrinsic to him yet relates him to something outside him.

There is a third way of ascribing, in which we ascribe to a subject something existing outside it, but which still qualifies it in some way. For even intrinsic1 accidents are ascribed to substances in that way [as qualifying]: not by saying a human being is whiteness but by saying a human being is white. Such qualification by something outside is in one way2 common to every sort of thing, but in another way special to human beings. The common way in which something external can qualify a subject is as a cause or as a measure, for things are qualified as caused or measured by things outside them. Now there are four kinds of cause. Two of these— matter and form— are parts of the thing, of its essence; so any ascription to a subject made on their account will fall into the category that ascribes substance: as when we say that human beings are rational or have bodies. And goals don't cause except through agents, for a goal counts as a cause in so far as it moves an agent. So we are left with agents as the only causes which can give rise to qualification of a subject by something outside. To qualify something by

Structures of Things in General its agent cause falls into the category that ascribes a passion

[or change suffered], for suffering or undergoing change is nothing more than taking on something from an agent; and the opposite qualification of an agent cause by its effect falls into the category of action, for action is an actualization from an agent in something external, as we have said above.

As to measures, some are extrinsic and others intrinsic.

Intrinsic measures are things like a subject's own length, breadth, and depth, which qualify it by what inheres in it intrinsically, and so belong under the category that ascribes quantity. External measures are a thing's time and place. To qualify a thing by its time belongs to the category when; to qualify it by its place belongs to the category where, and also to the category position, which adds to place how the subject's parts are disposed in that place [sitting, standing, etc.]. Such an addition is not needed in the case of time, since being in time already implies a disposition of parts in time: time being the measure of the before-and-afterness of changes. So stating a thing's when or where qualifies it by its time or place.

What is left is the special case of human beings. Other animals are sufficiently equipped for survival by nature— they have horns to defend themselves, thick hairy skin to cover them, and hooves or the like for getting about without injury. And so when we call such animals armed or clothed or equipped with hooves, we are not in a way qualifying them by anything external but by parts of themselves. So this will belong to the category that ascribes substance, just like calling human beings handed or footed. But nature can't give human beings the same sort of equipment as animals, partly because that wouldn't go with the more subtle constitution of their bodies, partly because nature couldn't devise fixed tools to suit the variety of things that reason enables human beings to do. So instead of such equipment human beings must use the reason they have to devise for themselves external substitutes for what in other animals is intrinsic. As a result, when we call human beings armed or clothed or shod we are qualifying them by something external to them which is neither cause nor measure, and so belongs in a

Substance, Accidents, Action, Passion

special category that ascribes equipment. But note that this category does also apply to other animals, not of their own nature, but as used by human beings: as when we call horses caparisoned or saddled or armoured.

[Thomas's solution of his difficulties] So now we see how change can be one single thing, and yet give rise to two categories of ascription ascribing qualifica tions by different external things. For the agent, to which the category ascribing passion refers, is one external thing qualifying the subject; whilst the patient, referred to when qualifying something as an agent, is another. And so the first difficulty is solved.

The second difficulty is easy to solve. For our notion of change is made up not simply of what corresponds to it in the real world, but also of what our reasons have made of that. In the real world there is no more to change than an incomplete actualization, the start of some complete actualization in what is changing: in something turning white there is some beginning of whiteness. But this incomplete actualization can be seen as change only if we understand it as a kind of transition between two things: something preceding (which relates to it as potential to actual, so that change is seen as an actualization) and something following

(which relates to it as complete to incomplete or actual to potential, so that change is seen as [actualization] of some thing that exists in potentality, as we said earlier). Unless incomplete actualizations are seen as tending to further com pleteness, they will be seen as results of change, not as changes that something is still undergoing: as, for example, the state of something which had started to turn white but got interrupted immediately. With respect then to what is real in it, change belongs reductively to whatever genus the result of the change belongs to, in the way anything in complete is reductively what it would be if complete, as we have said. But with respect to what our reasons have made of change, namely, a sort of transition between two extremes, the notions of cause and effect are already implied, since without an agent cause nothing can be brought from poten-

Structures of Things in General tiality to actualization. In this respect change belongs to the categories of action and passion; for these two categories derive from the notions of agent cause and effect, as we have seen.

[Aristotle's text, 202b23—29] What then change is we have stated both generally and in particular. It is not difficult to see how to define each of its species. A modification of properties is an actualization of what is capable of modification of properties precisely as such: more clearly that change actualizes the potentialities of both agent and patient, generally and also in particular, building and healing, and the same of other changes.

[Summing up] Next, when he says What then change is, he defines change in particular. And he says that we have stated what change is both generally and in particular, since from what has been said about how to define change in general it is not difficult to see how to define its species. For if change is an actualiza tion of what is capable of change precisely as such, then a modification of properties is an actualization of what is capable of modification of properties precisely as such, and so on for other types of change.

And because a difficulty was expressed about whether change actualized what caused it or what underwent it, and it was shown that it actualized the agent by being from it, and the patient by being in it, to remove every difficulty let us say a little more clearly that change actualizes the potentialities of both agent and patient. And that also can be said in particular: building actualizes both builder and what he builds as such. And the same with healing, and other changes.

Passage 6 Essence and Existence Source: On Being and Essence (complete). Text from De Ente et

Essentia (Opera Omnia, Leonine edn., vol. xliii).

Essence and Existence

Date: 1252-6, first stay in Paris, aged about 30.

Type of passage and how to read: The work reads like an attempt to summarize and mediate between remarks made by past masters on the subject of essence and universals: especially Ibn Síná and Ibn

Rushd. It marks an early stage in the rejection by Thomas of a form-matter composition in non-bodily substances; and the conse quent ascription of an essence-existence composition to them.

Notes on translation: The words translated as 'being', 'existence', and 'essence' all derive from the Latin verb esse ('to be'). St Thomas conceives the being of a thing on the model of an activity which that thing exercises: call it the activity of being be-ing being. The quasi activity of 'be-ing' he refers to as esse or actus essendi, the 'to be' or the 'act of be-ing', and it is customary to translate it 'existence', though that English word is not as flexible as the Latin. What exerts this quasi-activity, the 'being' which is, he refers to as ens, a sort of bastard present participle of esse. And the complement, the 'being' that a being is, what it is, is referred to by many terms, of which essentia is one, a sort of abstract noun derived from yet another bastard present participle of esse. It corresponds to a similarly derived

Greek word: ousia. An English equivalent might be 'beingness'. So this work should really be called 'On Being and Beingness', or 'On Beings and their Being'. I have given way to custom and translated:

'On Being and Essence'.

Parallel reading: Cf. Passage 21: God is his own existence.

[Prologue] Since Aristotle1 says big mistakes grow from small begin nings and Ibn Síná2 says understanding begins with the notion of being [what is] and essence [isness], lest ignorance of these notions lead us astray, we must dispel their difficulty by saying what is meant by the word essence (and being), the various forms in which we come across it, and its relation to logical notions like genus, species, and differentiating charac teristic. And because human beings get their knowledge of simple, primary things from what is later and more complex, it will be best to start from what is easiest for us, learning first about being [what is] and then about essence [isness].

[Being] [1] Note then that Aristotle3 says there are two proper uses of the term being: firstly, generally for whatever falls into

Structures of Things in General

one of Aristotle's ten basic categories of thing, and secondly, for whatever makes a proposition true. These differ: in the second sense anything we can express in an affirmative proposition, however unreal, is said to be; in this sense lacks and absences are, since we say that absences are opposed to presences, and blindness exists in an eye. But in the first sense only what is real is, so that in this sense blindness and such are not beings.

[Essence] The word essence [isness] then refers to what is in the first sense, not the second; for things like lacks that can be in the second sense still don't have [isness or] essence. Hence Ibn

Rushd4 comments that being in the first sense expresses the isness of things. And because, as we have just said, being in this sense applies generally to all ten categories, essence must be something all the natures that sort different beings into their various genera and species have in common: being human is the essence of human beings, for example, and similarly for other things. Now what sorts things into their proper genus and species are the definitions that express what they are; so some philosophers have used the word whatness for essence, Aristotle himself frequently calling it the what-it-is-to-be-that: i.e. that which makes something what it is. The word form is also used, which Ibn Slna5 says means what gives a thing its stable identity. And yet another name is nature, in the first of four senses assigned to that word by Boethius:6 as meaning whatever understanding can grasp; for it is definition of essence that makes things under standable. In this sense Aristotle7 called every substance a nature. However, nature so understood seems to express essence as what underlies a thing's characteristic behaviour

(for nothing lacks a characteristic behaviour), whereas what ness expresses it as underlying the thing's definition, and essence refers to it as that through which and in which a being has existence.

But because being is used in a primary unqualified sense of substances, and in a secondary qualified sense of incidental properties, essence too belongs properly and truly to sub-

Essence and Existence

stances, but to incidental properties in a qualified sense. And though composite and non-composite substances both have essence, simple non-composite things have it more truly and excellently since they exist in a more excellent way, as the cause of composite things (this is true of God at least, who is the first of all simple sybstances). But because the essence of such substances is more hidden from us, it will be best if we start with what is easier, learning first about the essence of composite substances.

[Essence in composite substances] [2] Note that what composes composite substances is material and its form (humans, for example, contain body and soul), and neither of these by itself can be the thing's essence. This is clear enough for anything's material, because things are known and sorted into species and genus by their essence, but a thing isn't known by its material, and we determine its species or genus not by its material but by the way that material is actualized. But neither can form alone be a composite substance's essence, though some think so.

For a thing's essence, we have said, is expressed by its defini tion, and unless the definition of a physical substance included not only its form but its material, definitions of natural objects wouldn't differ from those of mathematical objects. It won't do to say that the material only enters the definition of a physical substance as something added to its essence from outside, since that kind of definition characterizes incidental properties, which have an incomplete essence and need to refer in their definitions to their subject, lying outside their own genus. Clearly then essence involves both material and form. But it doesn't simply express a relationship between material and its form or something supervening on both, because this would be incidental and extraneous to the thing and not identify it to the mind, as essence must. For form actualizes its material and makes it into a this-thing, actual and existent, so that anything that supervenes can no longer actualize the material, simply speaking, but only in this or that way as incidental properties do: whiteness making it actually white, for example. Acquiring such a form is not

Structures of Things in General coming to be, simply speaking, but only in this or that respect.

So what is left is that in composite things essence expresses a composite of material and form. This agrees with Boethius' comment8 that ousia means the composite, where ousia, as he also tells us,9 is Greek for essence; and with Ibn Síná's assertion10 that the whatness of composite substances is their very compositeness of form and material, and also with Ibn

Rushd's comment11 that the nature that species of generable things have is a sort of mixture, i.e. composite of material and form. And it also agrees with reason, since the existence of a composite substance belongs not just to its form or to its material but to the composite itself. Now it is by having essence that things exist; so the essence which allows us to call it existent must consist not of form alone or material alone but of both; even though form alone causes— in its own way— that existence. For things composed of several elements are always named in this way: not because of any single element but because of the complex of both; a sweet taste, for example, is caused by the action of digestive heat on moist matter, but though heat causes sweetness we don't call hot bodies sweet, only bodies with that complex of hot and moist that constitutes a sweet taste.

But now, because their material makes things individual, it could seem that an essence made up of material and form together would not be general but particular, and that, since definitions express essence, nothing could be given a general definition. So note that what makes things individual is not material as such but demarcated material, by which I mean material thought of as underlying certain defined dimensions.

Now material thought of in this way doesn't enter the defini tion of human being as human being (though it would enter

Socrates' definition if he had one); what enters the definition of human being is undemarcated material, not this flesh and these bones but flesh and bones in general, the undemarcated material of human beings. Clearly then Socrates' essence differs from human essence only by being demarcated.

Socrates, as Ibn Rushd12 says, is nothing more than animality plus rationality; those are what he is.

Essence and Existence

And the specific essence of something also differs from its generic essence by being demarcated, though the method of demarcation is different: for individuals are demarcated within species by dimensionally defined material, but species within genus by a defining differentiation taken from the form. This determination or demarcation of species within genus is not because of anything existing in the specific essence that was totally absent from the generic essence; indeed everything present in a species is present in the genus in a non-determined way. For if only part of a human being and not the whole was animal, human beings wouldn't be animals, since wholes aren't named after parts.

To see how this is possible, contrast body as component of an animal with the genus of bodies, for they must be dif ferent. The word body has several senses. As naming a sub stance, it names something of such a nature as to occupy three demarcated dimensions, the three dimensions demarc ated being body-as-quantity, [the solid body of mathematics].

Now things with one perfection are not excluded from further perfections: human beings, able by nature to sense, are further able by nature to understand. And in the same way things by nature able to occupy three demarcated dimen sions can add to that perfection others like life or the like. So this word body sometimes means a thing of a form such that it can occupy three dimensions, but stopping there: in other words the form produces no further perfection, so that any thing extra lies outside the meaning of body so understood; and in this sense body names a component and material part of animals, with its animating soul lying outside the meaning of body so defined and supervening upon it, so that the animal is made up of two component parts, body and soul.

But the same word body sometimes means a thing of a form such that it can occupy three dimensions, whatever form that be, whether producing further perfections or not; and in this sense body names a genus that includes animals, since now there is nothing in animal that isn't already implicit in body.

For the animating soul isn't a different form from the one enabling the thing to occupy three dimensions, and when we said body is anything of a form such that it can occupy three

Structures of Things in General dimensions we were meaning whatever form that be: be it an animal soul, or stone-ness, or anything else. And in this way the animal form was implicit in the form of body, body being its genus.

The same relation holds between animal and human. If animal names only things perfect enough to be able to sense and move about of themselves, stopping short of any further perfections, then any supervening perfection would be a fellow component with animal and not something already implicit in the notion of animal, and animal would not name a genus.

Animal as genus means anything of a form able to sense and move about, whatever form it be: a soul that only senses, or one that both senses and understands. In this way then a genus expresses non-determinately the whole of what the species expresses (not only the material), and in the same way a differentiating characteristic expresses the whole (not only the form), and the definition or species also expresses the whole: but all in different ways. The genus expresses the whole through a name which determines the thing's material but falls short of the [full] determination proper to the form: though not itself that material, it bases itself on the material; body is a clear example, naming something of a perfection such that it can occupy three dimensions, a perfection which is a sort of material for further perfections. A differentiating characteristic on the other hand names something by its determinate form, abstracting at first from the material it determines; living is a clear example, meaning endowed with soul, for this doesn't determine what is living, a body or something else; which is why Ibn Slná13 says genus is not part of the essence of a differentiating characteristic but something extraneous to it in the way subjects enter the definitions of their incidental properties, and also why

Aristotle14 remarks that genus is not predicated of dif ferentiating characteristics as such except perhaps in the way subjects are predicated of their properties. But a definition or species comprehends both the determinate material expressed by the name of the genus and the determinate form expressed by the name of the differentiating characteristic.

And now we can see why genus, species, and differentiat ing characteristic correspond to material, form, and com-

Essence and Existence

posite in the natural world, though differing from them; for a thing's genus is not its material but a name for the whole derived from its material, and its differentiating characteristic is not its form, but a name for the whole derived from its form. Thus we call humans logical animals made up of body and soul, but not made up of animality and logicality; for a human being is a third thing composed from two com ponents, body and soul, both differing from the whole (for a human being is neither soul nor body). Whereas if human being were said in some sense to be composed of animal being and logical being, that would not be two component things making a third thing, but two component concepts making a third concept. The concept animal expresses a thing's nature without determining its specific form, seeing it only as material for that final perfection; the concept logical, the differentiating characteristic [of a human being] pro vides the determination to that specific form; and the concept of the thing's species or definition puts these two concepts together. And just as a thing made up of two others is not identified with them, so a concept isn't identified with any of its component concepts: the definition is neither the genus nor the differentiating characteristic.

Now the fact that a genus expresses the whole essence of its species doesn't mean that all its different species have one and the same essence. For the genus's unity is precisely one of non-determination and undifferentiation: what the genus expresses is not one single nature present in the different species upon which some other thing— the differentiating characteristic— supervenes, determining it like a form deter mining a single material; but the genus expresses a form without determining it to be this or that form, and the differentiating characteristic expresses it determinately, the form being the same one expressed non-determinately by the genus. This led Ibn Rushd15 to say that the ultimate material of things has the unity of total formlessness, whereas a genus has the unity of the commonness of the form it expresses. Clearly then adding differentiating characteristics removes the non-determination that unified the genus and what we are left with is species differing in essence.

And because, as we said earlier [pp. 94—5], a thing's specific

Structures of Things in General nature leaves undetermined which individual it is (just as its generic nature leaves undetermined what species it is), the species of an individual expresses— indistinctly— the whole essence of that individual (just as the genus of a species expresses implicitly but indistinctly the whole of what the species expresses determinately). And because this is the way the phrase human being expresses the essence of his species, we say Socrates is a human being. But if the same specific nature were to be expressed in a way that explicitly excluded the demarcated material which made him an individual, then the specific nature would be conceived of as a component part: the way the word humanness expresses it, since human ness means what makes humans humans. Now demarcated material isn't something which makes humans humans, and can't be included among what makes humans humans.

Humanness, however, is a concept including only what makes humans humans, so that demarcated material is clearly cut out or excluded from its meaning; and consequently, since we don't call the whole its part, we don't say a human being (or Socrates) is his humanness. That is why Ibn Síná16 says no composite is its own 'whatness', even though that whatness is itself composed; humanness, though composite, is not a human— it needs to be taken on by something, namely, demarcated material.

But because, as we have said [pp. 9 4 -5 ], form demarcates species within a genus whereas material demarcates in dividuals within a species, our word for the generic in a thing— cutting out the form as determinately perfecting the species— names a material part of the whole (in the way body names the material part of humans). In contrast, our word for the specific in a thing, cutting out demarcated material, expresses a formal part. So humanness expresses a sort of form called the form of the whole: not meaning something added over and above a thing's entitative parts— its form and material— as the form of house is added over and above its component parts, but rather meaning the form which is the whole, the complex of form and material cutting out only what serves to demarcate the material.

So human essence is expressed by both words: human

Essence and Existence

being and humanness, but differently, as we have said [p. 98]. For the phrase human being expresses it as a whole (not cutting out demarcated material but including it implicitly and indistinctly in the way we said a genus includes its differentiating characteristics): so individuals can be called human beings. But the .word humanness expresses it as a part

(including in its meaning only what belongs to humans as humans and cutting out all demarcation), and so we don't call an individual human being humanness. This is why the word essence is sometimes asserted of things (Socrates, we say, is an essence of sorts) and sometimes denied (Socrates' essence, we say, is not Socrates).

[How essence relates to logical notions like genus, species, and differentiating characteristic in composite substances]

[3] So now that we have seen what the word essence means in composite substances, we must see how it is related to the notions of genus, species, and differentiating characteristic.

Now notions like genus, species, and differentiating charac teristic attach to something that can be attributed to this demarcated singular. So general notions like genus or species can't attach to essence as a component part (expressed by words like humanness or animalness). This is the reason Ibn

Síná17 says logicalness is not a differentiating characteristic but a source of differentiation, and for the same reason humanness is not a species and animalness not a genus. In the same way a notion like genus and species can't attach to essence as something existing outside singulars in the way

Platonists propose, for then genus and species could not apply to this individual: one can't say Socrates is something separated from him, nor would that separate thing help you to know this singular. So the only alternative is that notions like genus and species attach to essence as the whole (ex pressed by words like human being or animal), as implicitly and indistinctly including the whole of what is present in the individual.

However, nature or essence so understood can be con sidered in two ways. Firstly, on its own, considering what properly defines it, so that only what belongs to it as such is

Structures of Things in General true of it and everything else attributed to it false. Thus, being logical and animal and whatever else defines human beings belongs to them as human, but being white or black or anything else not included in humanness doesn't belong to human beings as human. So, asked whether nature con sidered in this way is one or many, one should answer neither, since neither is contained in what we understand by humanness though both can belong to it coincidentally: if manyness was contained in humanness it could never be one as it is in Socrates, and if oneness was part of its definition then Socrates would be Plato and the nature couldn't be realized more than once. The second way of considering nature is as existing in this or that: and considered in this way something can be attributed to it coincidentally by reason of what possesses the nature, as a human being can be called white since Socrates is white though white doesn't attach to human beings as human. Nature in this sense exists firstly in singulars and secondly in the mind: in both cases certain things are true of it coincidentally, and in singulars it also exists more than once in a diversity of singulars. None of these existences belong to nature in the first sense, considered on its own. For it is false to say that human being as such exists in this singular: if existing in this singular belonged to human beings as human no humans could exist outside it, and if not existing in this singular belonged to human beings as human that singular could never be human. But it is true to say that human being— though not as human being— exists in this or that singular or in the mind. Clearly then human nature considered on its own abstracts from all these existences but cuts none out, and it is nature considered in this way that is predicated of all individuals.

Nevertheless, one can't say general notions attach to nature so understood, since the notion of generality involves unity and commonness, neither of which belong to human nature considered on its own: for if commonness were part of what we understood by human, then wherever humanness was found commonness would be found too, which is false: for we don't find commonness in Socrates but everything in him is individuated. Nor can one say that notions like genus

Essence and Existence

and species attach to human nature as it exists in individ uals, since human nature is not present in individuals as a single unified something attaching to all in the way the notion of generality requires. So the only alternative is that notions like species attach to human nature as it exists in our understanding.

For human nature itself exists in our understanding abstracted from all individuation, but with a definition uni formly applicable to all individuals outside the mind, since it is a likeness of them all equally, and leads us to know them all as human beings. And out of this relationship the nature has to all individual human beings, our understanding con structs the notion of species and attributes that to the nature; so that Ibn Rushd18 says it is our understanding that works generality in things, and Ibn Slná19 says the same. And although nature in the understanding possesses this generality in regard to things outside the mind (being a single likeness of them all), it still, as existing in this or that understanding, is a particular mental idea. And that shows up Ibn Rushd's mistake20 in wanting to argue from the generality of the form in the understanding to a unity of mind in all men; because the generality attaches to the form not as existing in this understanding but as referring by way of likeness to things; just as the image or species present in one bodily statue and representing many men would undoubtedly have its own single existence in the statue's material despite its relationship of commonness as a common representation of many.

And because it is human nature considered on its own that is attributed to Socrates, and the notion of species doesn't attach to the nature considered on its own but is something coincidentally true of it as existing in understanding, the word species can't be attributed to Socrates (you can't say

Socrates is a species). This you couldn't avoid doing if the notion of species attached to human being as existing in Socrates, or to human being as human, considered on its own, for whatever attaches to human beings as human can be attributed to Socrates. Nevertheless, attributability to things is an essential property of a genus, forming part of its

Structures of Things in General definition. For attribution is something mind brings to com pletion by constructing propositional connections and dis connections, basing itself on the real-world unity possessed by the things being attributed to one another. So the notion of attributability can form part of the logical notion of genus which is likewise brought to completion by an act of mind; though what mind attributes the notion of attributability to, what it connects it with, is not the notion of genus itself, but rather that to which it also attributes the notion of genus, e.g. what it means by animal.

This then explains the relationship between essence or nature and the notion of species: the notion of species is not something attaching to essence considered on its own, nor something coincidentally true of it as existing outside the mind (as whiteness and blackness would be), but something coincidentally attached to it as existing in the mind. And this is also the way the notions of genus and differentiating characteristic attach to it.

[Essence in simple non-composite substances] [4] At this point, we still have to see how essence is present in separated [immaterial] substances like human minds,

[angelic] intelligences, and the first cause.

[The simpleness of intelligences] Now, though everyone concedes simple non-compositeness to the first cause, some people have wanted to introduce a compositeness of material and form into intelligences and minds, a position apparently first adopted by Ibn Gebirol.21

It contradicts the common opinion of philosophers, who had called such substances separated, i.e. from material, and proved them to exist without any material. The strongest such proof is drawn from their power of understanding. For we see that forms are only actually understandable when separated from material and material conditions, and the only thing that can make them actually understandable in this way is the power of some intelligent substance taking them in and acting on them. But if that is so all intelligent substances must be entirely free from material, neither con-

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taining it nor even being the sort of form material takes on (i.e. forms of matter). Nor can one say that intelligibility is impeded only by bodily material, not all material; for if only bodily material did it, since bodiliness comes from taking on bodily form, material's impeding of intelligibility would come from that form» But that can't be true, because this form too is actually intelligible, just like other forms, when abstracted from material.

So in minds and intelligences there is no composition of material and form to give them the same kind of essence that bodily substances have, but they are composed of form and existence, as we read in the book of Causes:22 intelligence is what has form and existence, where form means the simple whatness or nature they have. How this can be is easy to see, for when things are so related that one causes the other to exist, the cause can exist without what it causes but not vice versa. Now material and form are so related, form giving existence to the material. Material then can't exist with out form, but form, precisely as form, is not dependent on material. When we do find forms which can't exist except in material this is incidental to them and due to their dis tance from the ultimate pure actualization which is their first source; forms nearest to that first source subsist by them selves without material (for the whole genus of forms doesn't need material, as we have said), and such forms are the intelligences, in which essence and whatness doesn't have to differ from the form itself.

The difference then between the essence of composite and the essence of simple substances is that the former is not just form but a complex of material and form, whereas the latter is just form. And two other differences follow from this. The first is that, because of demarcated material as we have said, the essence of composite substances can be expressed as a whole or as a part, so that you can't say a composite thing is in all respects its own essence: a human being is not his whatness. But the essence of simple things— their form— can only be expressed as a whole, since there is no other thing taking the form on. So a simple substance is its own essence in every sense, and Ibn Síná23 can say: the simple's whatness

Structures of Things in General is its very self, nothing else takes it on. The second dif ference is that entities of composite things when taken on by demarcated material are multiplied by the material's divided ness, and many individuals can exist in the same species.

Because the essence of simple things is not taken on by material it cannot be multiplied in this way, and in such substances one can't have many individuals in one species, but each individual is a species, as Ibn Síná24 explicitly asserts.

[The compositeness of intelligences] Such substances then are just forms without material. How ever, they are not totally simple, not pure actualizations, but have potentiality mixed in. And this can be shown as follows. No essence or whatness can be understood without its parts. So what isn't contained in our understanding of an essence must be something extraneous added on to it. But all entities and whatnesses can be understood without under standing their existence: I can understand what humans or phoenixes are without knowing whether such things really exist; so clearly a thing's existence differs from its essence or whatness. A possible exception would be something whose essence was its own very existing, but there could only exist one primary thing like that; for, to be many, things must add some differentiating characteristic to a genus to make many species, or one form must be taken on by different material to make many individuals in a species, or one must exist on its own while the other exists in something (in the way heat, if it could exist separately, would by its very separateness differ from heat existing in something). Now the thing we are positing— something that just is existence, so that its very existing subsists— can't add on differentiating charac teristics without ceasing to be just existing and becoming existence plus form; and even less can it add on material, because then it would straight away be not subsistent but materialized existence. So there is no alternative: only one thing that is its own existence can exist, and all other things must have an existence differing from their whatness or nature or form. Intelligences then must have existence over

Essence and Existence

and above their form; and that explains the saying: intel ligence is what has form and existence.

Now a thing's attributes are caused either from within its nature (like a human being's sense of the ridiculous) or by some extrinsic source (like light in the atmosphere by the sun). But the very existence of a thing can't be caused by its own form or whatness— I am talking of agent causality— because then something would be causing itself and bringing itself into existence, which is impossible. So everything in which existence and nature differ must get its existence from another. And because all getting from another must eventually lead to something possessing of itself, there must be something which can ultimately cause everything's existence because it is its own existence; otherwise the causes would go on for ever, with everything which is not just existence requiring a cause of its existence, as we have said.

Clearly then intelligences are form and existence, and get their existence from a first existent which is just existence: the ultimate cause which is God.

Now whatever acquires something from another has a potentiality for what it acquires, a potentiality that what is acquired actualizes; so the very whatness or form which an intelligence is has a potentiality for the existence it acquires from God, and the acquired existence actualizes it. So there is potentiality and actualization in intelligences, though if we called that form and material we would equivocate in the way that Ibn Rushd25 says we would equivocate were we to say intellectual substances, like bodily substances, underwent change, or took on or were subject to form (all of which seem to apply to material things as such). Now because, as we have said, the whatness of an intelligence is the intel ligence itself, the whatness or essence is that which exists, and the existence it receives from God is that by which it really subsists in nature; so some people say such things are composed of that which and that by which, or from that which exists and existence, as Boethius26 says. But because there is this potentiality and actuality in intelligences, there is no difficulty about having more than one of them, some thing that would have been impossible in the absence of

Structures of Things in General potentiality. As Ibn Rushd27 says: if we hadn't known mind could be 'possible' [i.e. receptive] we wouldn't have been able to have more than one separate substance. So they are distinguished among themselves by their degree of potentiality and actualization, higher intelligences nearer to their source being more actualized and less potential, and so on down until you finally reach the human mind, the lowest ranked of intellectual substances. According to Ibn Rushd,28 our receptive mind is related to forms that can be understood, as ultimate material (lowest ranked of what can be sensed) is related to forms that can be sensed; and Aristotle29 for that reason compares it to a blank slate. And, being of all intellectual substances the most potential, it so borders on material things that it even draws one of them in to share its own existence, and from mind and body there results a single existent composite thing, although mind's possession of that existence is not dependent on body. And below the form which is our mind we find other forms more potential, so close to material that they can't exist except as forms of material; and these are ordered in degree right down to the first forms of elements, nearest of all to material, and active only in the sense of clothing material with the active and passive and other qualities needed to dispose it for form.

[Essence in God, intelligences, and material things] [5] What we have been saying explains the diverse ways things have essence. For there are three ways substances possess essence.

[God] God's essence is identified with his own very existence; so that some philosophers have denied any essence or whatness to God at all, because he hasn't essence distinct from his existence. As a result he isn't a member of any genus: for all members of genuses must have whatness distinct from their existence, since they are not diversified in their generic or specific whatness or nature as nature, although each differs in existence. Saying God is simply existence doesn't force us into the error of those who say God is the existence in

Essence and Existence

general by which each thing exists. Existence in God is of such a sort that it can't be added to, distinct therefore from all other existence by its very purity; as the book of Causes30 says: its own pure goodness makes the first cause, pure existence, individual. But existence in general is not con ceived as either including addition or prohibiting addition; for otherwise nothing that added anything to existence could be conceived of as existing. In the same way, that God is simply existence doesn't mean he has to lack other perfec tions and excellences. Rather he possesses every perfection of every genus— his perfection is without qualification, as Aristotle31 and Ibn Rushd32 both say— possessing them more excellently than anything else can because in him is unified what in others is diverse. And this is because all these perfections belong to him simply as existing; just as someone exercising the activities of all qualities through one quality would possess all qualities in that one, so God in his very existing possesses all perfections.

[Intellectual substances and essence] Created intellectual substances realize essence in a second way: in them essence, though immaterial, differs from existence. So they don't have a stand-alone existence, but an acquired existence, circumscribed and limited to what the acquiring nature can take on; though they have a stand-alone nature or whatness, not acquired by any material. And so intelligences are described in the book of Causes33 as unlimited below but limited above: limited in existence which they acquire from above, but unlimited below since their forms are not limited to what some acquiring material can take on. Consequently, in such substances there is only one individual in a species, as we have already said [p. 104].

The exception is the human mind, because of the body it is joined to. And here, though its individuality depends to start with on what body it happens to be joined to (since it acquires individual existence only in the body it actualizes), nevertheless its individuality doesn't have to perish when the body is taken away, because the existence it has in its own right— an existence individuated by it being made the form

Structures of Things in General of this body— from then on always stays individuated. As Ibn Síná34 says: that minds are one or many depends on bodies in the beginning but not in the end.

[Intellectual substances and genus and species] Again, because whatness in these substances differs from existence, they are categorizable, and can be assigned genus and species and characteristic differences, though what those differences really are we can't see. Even when things can be sensed we don't know what really differentiates them but use consequent incidental differences as symptomatic of dif ferences in essence, in the way effects are symptomatic of causes: two-legged, for example, to distinguish humans. But even incidental characteristics of immaterial substances are unknown to us, and so we can't distinguish them either in themselves or through incidental differences.

Note, however, that genus and differentiating charac teristic don't arise in the same way in these substances and in substances we can sense. In the substances we sense genus arises from what is material in a thing and the differentiating characteristic from what is formal in it. Thus Ibn Síná35 says that in things composed of material and form the form is a simple differentiation of what it forms (though, as Ibn Síná36 himself says, the form makes rather than is the differentia tion), where the differentiation is called simple because it arises from a single part of the thing's whatness, namely, its form. Immaterial substances, however, are their own simple whatnesses, and differentiation in them must derive from the whole of their whatness and not just a part of it, and so Ibn

Síná37 says that only species whose essence is composed of material and form have a simple differentiation. And in such things genus too derives from their whole essence, but in a different way. For immaterial substances agree with one another in immateriality but differ in perfection measured on a scale running from potentiality to pure actualization. So genus derives from features like intellectuality, consequent on their immateriality, whilst differentiation derives from their degree of perfection, something unknown to us. You can't argue that such differences of degree are incidental because

Essence and Existence

not differences of kind: true, taking on one and the same form more or less perfecdy doesn't make a difference in kind

(white and less white are degrees of the same whiteness), but when the shared forms and natures themselves are of dif ferent degrees of perfection we get difference in kind, as in Aristotle's38 account jof nature advancing by degrees from plants through intermediate things to animals. Nor must intellectual substances always be pairwise divided by true differentiations, since Aristotle39 notes that this can't be the case for everything.

[Composite substances] Substances composed of material and form realize essence in yet a third way, in which both existence is taken on and thus limited by being acquired from another, and their nature or whatness too is taken on by demarcated material. Such substances then are limited both above and below; and already, because of the divisions in demarcated material, have more than one individual in a species. And how essence in such things is related to logical concepts we have said earlier [p. 99].

[How essence is realized in incidental properties] [6] Now that we have explained how essence is realized in all substances, it remains only to see how it is realized in incidental properties.

And since, as we have said [p. 92], essence is what is expressed in a definition, incidental properties will have essence in whatever way they have definition. Now they are not completely definable; any definition of them must mention their subject too, because they cannot exist on their own apart from their subject but incidental property and subject join together to yield something that exists in an incidental sense. In the same way, form and material join to yield something that exists as a substance, so that forms and material of substances also have incomplete entities; for in defining forms of substances too we must mention what is formed, adding in something outside their genus, just as in defining incidental forms: thus a natural philosopher's defini-

Structures of Things in General tion of mind will mention body, since his interest in mind is its role of giving form to the physical body.

However, substantial and incidental forms differ to this extent: not only does substantial form have no existence of its own apart from the material upon which it supervenes but the material doesn't either, so that existence of a selfsubsistent thing waits on the joining of the two into some thing essentially one, a joining, therefore, which yields an essence. Form then, though having no complete essence of its own, forms part of a complete essence. But that which incidental properties supervene on already exists complete in itself, subsisting in its own existence, an existence naturally prior to anything that incidentally supervenes. So when what supervenes is joined to that, it produces not the kind of existence in which things subsist as self-existent, but a kind of secondary existence: an existence that the subsistent thing can be conceived to exist without, in the way we can con ceive anything that comes first without what comes second.

From subject and incidental property, then, we get something incidentally, not essentially, one, and the joining doesn't yield an essence as the joining of form and material does. So an incidental property neither has complete essence nor does it form part of a complete essence: because it exists only in a qualified sense it has essence only in a qualified sense.

But because what is most fully and truly of a certain kind is the source of all later instances of the kind (fire, the supremely hot, is the source of the heat of hot things, as Aristotle40 says), substance, as primarily existent, most fully and truly having essence, must be the source of incidental properties, which are existent in a secondary and qualified sense. Now this happens in different ways, for a substance has parts— its material and its form— and certain incidental properties derive principally from form and certain from material. Now there is one form— mind— which can exist independently of any material, but no material can exist except as formed; so, among incidental properties con sequent on form, one— understanding— has nothing in common with material, making use of no bodily organ as Aristotle proves,41 while others consequent on form— sensing— have their material side; but, among incidental

Essence and Existence

properties consequent on material, all have their formal side.

Yet there are differences among these incidental properties consequent on material: some of them are consequent on material in a certain specific form— male and female, for example, on material in animal form, according to Aristotle42— and persist only equivocally in the absence of animal form; but others are consequent on material in its general form, so persist in the absence of the specific form— the African's black skin derives not from his human form but from a chemical compounding of elements which persists after death. And because material makes things individual, and form gathers them into genus and species, incidental properties consequent on material are incidental to individ uals, distinguishing them within the same species, whereas incidental properties consequent on form characterize genuses or species and are common to all members of the genus or species: a sense of the ridiculous, for example, which is consequent on the human form, since the ridiculous is some thing only human minds can grasp.

Note too that a substance is sometimes the source of incidental properties in full actualization— the heat of fire never fails to be hot— and sometimes the source only of a susceptibility which some exterior agent must actualize— as an independently shining light must actualize the transparency of the atmosphere; and that in the latter case the susceptibility is an inseparable incidental, but the completion by a change or the like is separable, because it has a source outside the thing's essence or not forming part of it.

[How essence relates to logical notions like genus and species in incidental properties] Note too that genus, differentiating characteristic, and species arise in a different way in incidental properties and in substances. Since form and material in substances yield something essentially one, joining into a single nature categorizable in the strict sense as a substance, the concrete nouns expressing the composite thing— e.g. human, animal— express its strict genus and species; form and material them selves, however, are not categorizable in this way, but only reductively in the way elements of a thing are said to belong

Structures of Things in General to its genus. But subject and incidental property yield nothing essentially one, their joining resulting in nothing to which the concept of genus or species can be strictly applied. So incidental properties as expressed by concrete nouns— whites, musicians— belong to a category reductively, and not as species or genus unless they are expressed abstractly— whiteness, musicality.

Note too that incidental properties aren't composed of material and form, so genus in them can't derive from the material nor differentiating characteristic from form as in composite substances. Their primary genera [or categories] must derive from their very mode of existing, in the way existing is divided into a hierarchy of senses by Aristotle's ten categories: quantity as measuring substances, for example, and quality as modifying them, and so on for the others.43

The differentiating characteristics of incidental properties on the other hand derive from the diversity of sources causing them. Properties peculiar to a subject derive from intrinsic factors peculiar to that subject, so the subject itself takes the place of a differentiating characteristic in definitions of the property abstractly expressed and strictly categorized— snubness is curvedness of nose. But conversely, in definitions of the property concretely expressed, the subject takes the place of the genus, and it is then defined as composite sub stances are, by deriving the genus from the matter— the snub is a curved nose. A similar thing happens when one accident is the source of another, as acting, being acted on, and quantity cause relationships, and so are referred to by Aristotle44 when distinguishing relationships. But because the exact cause of incidental properties is not always clear, we sometimes differentiate incidental properties by their effects, differentiating colours, for example, as dark and light, which are effects of the abundance or scarceness of light that diversifies colours.

[Summing-up] In this way, then, it is clear how essence is realized in substances— composite and simple— and in their incidental properties, and how logical concepts of generality arise in all

Essence and Existence

except the first supremely simple [being], whose simpleness refuses to be placed in either genus or species, and cannot therefore be defined, in whom may this discourse have its end and its fulfilment. Amen.

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