impossible, &c. are often used by philosophers and metaphysicians
and proper meaning. As for instance; if any one should affirm after this manner, That it is necessary for a man, or what must be, that he should choose virtue rather than vice, during the time that he prefers virtue to vice; and that it is a thing impossible and irresistible, that it should be otherwise than that he should have this choice, so long as this choice continues; such a one would use the terms must, irresistible, &c. with either insignificance, or in some new sense, diverse from their common use; which is with reference, as has been observed, to supposable opposition, unwillingness, and resistance; whereas, here, the very supposition excludes and denies any such thing: for the case supposed is that of being willing, and choosing.
5. It appears from what has been said, that these terms necessary, impossible, &c. are often used by philosophers and metaphysicians in a sense quite diverse from their common and original signification; for they apply them to man cases in which no opposition is supposable. Thus they use them with respect to God's existence before the creation of the world, when there was no other being; with regard to many of the dispositions and acts of the divine Being, such as his loving himself, his loving righteousness, hating sin, &c. So they apply them to many cases of the inclinations and actions of created intelligent beings wherein all opposition of the Will is excluded in the very supposition of the case.
Metaphysical or philosophical Necessity is nothing different from their certainty. I speak not now of the certainty of knowledge, but the certainty that is in things themselves, which is the foundation of the certainty of the knowledge, or that wherein lies the ground of the infallibility of the proposition which affirms them.
What is sometimes given as the definition of philosophical Necessity, namely, "That by which a thing cannot but be," or "where by it
cannot be otherwise," fails of being a proper explanation of it, on two accounts: First, the words can, or cannot, need explanation as much as the word Necessity; and the former may as well be explained by the latter, as the latter by the former. Thus, if any one asked us what we mean, when we say, a thing cannot but be, we might explain ourselves by saying, it must necessarily be so; as well as explain Necessity, by saying, it is that by which a thing cannot but be. And Secondly, this definition is liable to the fore-mentioned great inconvenience; the words cannot, or unable, are properly relative, and have relation to power exerted, or that may be exerted, in order to the thing spoken of; to which as I have now observed, the word Necessity, as used by philosophers, has no reference.
Philosophical Necessity is really nothing else than the FULL AND FIXED CONNECTION BETWEEN THE THINGS SIGNIFIED BY THE SUBJECT AND PREDICATE OF A PROPOSITION, which affirms something to be true. When there is such a connection, then the thing affirmed in the proposition is necessary, in a philosophical sense; whether any opposition or contrary effort be supposed, or no. When the subject and predicate of the proposition, which affirms the existence of any thing, either substance, quality, act, or circumstance, have a full and CERTAIN CONNECTION, then the existence or being of that thing is said to be necessary in a metaphysical sense. And in this sense I use the word necessity, in the following discourse, when I endeavor to prove that necessity is not inconsistent with liberty.
The subject and predicate of a proposition, which affirms existence of something, may have a full, fixed, and certain connection several ways.
(1.) They may have a full and perfect connection in and themselves; because it may imply a contradiction, or gross absurdity, to suppose
them not connected. Thus many things are necessary in their own nature. So the eternal existence of being generally considered, is necessary in itself: because it would be in itself the greatest absurdity, to deny the existence of being in general, or to say there was absolute and universal nothing; and is as it were the sum of all contradictions; as might be shown if this were a proper place for it. So God's infinity and other attributes are necessary. So it is necessary in its own nature, that two and two should be four; and it is necessary that all right lines drawn from the center of a circle to the circumference should be equal. It is necessary, fit and suitable, that men should do to others, as they would that they should do to them. So innumerable metaphysical and mathematical truths are necessary in themselves: the subject and predicate of the proposition which affirm them, are perfectly connected of themselves.
(2.) The connection of the subject and predicate of; proposition, which affirms the existence of something, may be fixed and made certain, because the existence of that thing is already come to pass; and either now is, or has been; and so has, as it were, made sure of existence. And therefore, the proposition which affirms present and past existence of it, may by this means be made certain and necessarily and unalterably true; the past event has fixed and decided the matter, as to its existence; and has made it impossible but that existence should be truly predicated of it. Thus the existence of whatever is already come to pass, is now become necessary; it is become impossible it should be otherwise than true, that such a thing has been.
(3.) The subject and predicate of a proposition which affirms something to be, may have a real and certain connection consequently; and so the existence of the thing may be consequently necessary; as it may be surely and firmly connected with something
else, that is necessary in one of the former respects. As it is either fully an; thoroughly connected with that which is absolutely necessary in its own nature, or with something which has already received and made sure of existence. This Necessity lies in, or may be explained by, the connection of two or more propositions one with another.----Things which are perfectly connected with other things that are necessary, are necessary themselves, by a Necessity of consequence.
And here it may be observed, that all things which are future, or which will hereafter begin to be, which can be said to be necessary, are necessary only in this last way. Their existence is not necessary in itself; for if so, the always would have existed. Nor is their existence become necessary by being already come to pass. Therefore, the only way that any thing that is to come to pass hereafter is or can be necessary, is by a connection with something that is necessary in its own nature, or something that already is, or has been; so that the one being supposed the other certainly follows.--And this also is the only way that all things past, excepting those which were from eternity, could be necessary before they come to pass; and therefore the only way in which any effect or event, or any thing whatsoever that ever has had or will have a beginning, has come into being necessarily, or will hereafter necessarily exist. And therefore this is the Necessity which especially belongs to controversies about the acts of the will.
It may be of some use in these controversies, further to observe concerning, metaphysical Necessity, that (agreeable to the distinction before observed of Necessity, as vulgarly understood) things that exist may be said to be necessary, either with a general or particular Necessity. The existence of a thing may be said to be necessary with a general Necessity, when, all things considered, there is a foundation for the certainty of their existence; or when in
the most general and universal view of things, the subject and predicate of the proposition, which affirms its existence, would appear with an infallible connection.
An event, or the existence of a thing, may be said to be necessary with a particular Necessity, when nothing that can be taken into consideration, in or about a person, thing, or time, alters the case at all, as to the certainty of an event, or the existence of a thing; or can be of any account at all, in determining the infallibility of the connection of the subject and predicate in the proposition which affirms the existence of the things; so that it is all one, as to that person, or thing, at least, at that time, as if the existence were necessary with a Necessity that is most universal and absolute. Thus there are many things that happen to particular persons, in the existence of which no will of theirs has any concern, at least, at that time; which, whether they are necessary or not, with regard to things in general, yet are necessary to them, and with regard to any volition of theirs at that time; as they prevent all acts of the will about the affair.----I shall have occasion to apply this observation to particular instances in the following discourse.---Whether the same things that are necessary with a particular Necessity, be not also necessary with a general Necessity, may be a matter of future consideration. Let that be as it will, it alters not the case, as to the use of this distinction of the kinds of Necessity.
These things may be sufficient for the explaining of the terms necessary and Necessity, as terms of art, and as often used by metaphysicians, and controversial writers in divinity, in a sense diverse from, and more extensive than, their original meaning, in common language, which was before explained.
What has been said to show the meaning of the terms necessary and necessity, may be sufficient for the explaining of the opposite terms, impossible and impossibility. For there is no difference, but only the latter are negative, and the former positive. Impossibility is the same as negative necessity, or a Necessity that a thing should not be. And it is used as a term of art in a like diversity from the original and vulgar meaning, with Necessity.
The same may be observed concerning the words unable and inability. It has been observed, that these terms, in their original and common use, have relation to will and endeavor, as supposable in the case, and as insufficient for the bringing to pass the thing willed and endeavored. But as these terms are often used by philosophers and divines, especially writers on controversies about Free Will, they are used in a quite different and far more extensive sense, and are applied to many cases wherein no will or endeavor for the bringing of the thing to pass is or can be supposed.
As the words necessary, impossible, unable, &c. are used by polemic writers, in a sense diverse from their common signification, the like has happened to the term contingent. Any thing is said to be contingent, or to come to pass by chance or accident, in the original meaning of such words, when its connection with its causes or antecedents, according to the established course of things, is not discerned; and so is what we have no means of foreseeing. And especially is any thing said to be contingent, or accidental, with regard to us, when it comes to pass without our foreknowledge, and besides our design and scope.
But the word contingent is abundantly used in a very different sense; not for that whose connection with the series of things we cannot discern, so as to foresee the event, but for something which has
absolutely no previous ground or reason, with which its existence has any fixed and certain connection.
PART I.
Section IV.
OF THE DISTINCTION OF NATURAL
AND MORAL NECESSITY, AND INABILITY
That Necessity which has been explained, consisting in an infallible connexion of the things signified by the subject and predicate of a proposition, as intelligent beings are the subjects of it, is distinguished into moral and natural Necessity.
I shall not now stand to inquire whether this distinction be a proper and perfect distinction; but shall only explain how these two sorts of Necessity are understood, as the terms are sometimes used, and as they are used in the following discourse.
The phrase, moral Necessity, is used variously: sometimes it is used for a Necessity of moral obligation. So we say, a man is under Necessity, when he is under bonds of duty and conscience, from which he cannot be discharged. Again, the word Necessity is often
used for great obligation in point of interest. Sometimes by moral Necessity is meant that apparent connexion of things, which is the ground of moral evidence; and so is distinguished from absolute Necessity, or that sure connexion of things, that is a foundation for infallible certainty. In this sense, moral Necessity signifies much the same as that high degree of probability, which is ordinarily sufficient to satisfy mankind, in their conduct and behavior in the world, as they would consult their own safety and interest, and treat others properly as members of society. And sometimes by moral Necessity is meant that Necessity of connexion and consequence, which arises from such moral causes, as the strength of inclination, or motives, and the connexion which there is in many cases between these and such certain volitions and actions. And it is in this sense, that I use the phrase, moral necessity, in the following discourse.
By natural necessity, as applied to men, I mean such Necessity as men are under through the force of natural causes; as distinguished from what are called moral causes, such as habits and dispositions of the heart, and moral motives and inducements. Thus men, placed in certain circumstances, are the subjects of particular sensations by Necessity: they feel pain when their bodies are wounded; they see the objects presented before them in a clear light, when their eyes are opened: so they assent to the truth of certain propositions, as soon as the terms are understood; as that two and two make four, that black is not white, that two parallel lines can never cross one another; so by a natural Necessity men's bodies move downwards, when there is nothing to support them.
But here several things may be noted concerning these two kinds of Necessity.