Can God's Existence be Proved? Four Approaches
Can God's Existence be Proved? Four Approaches
The relationship between faith and reason is often discussed in terms of whether God's existence can be proved and whether such proof would be adequate to bring a nonbeliever to faith. Although some writers have suggested that this is the case, the general consensus within Christian theology seems to be that, although reason does not bring individuals to faith in God, believers are nonetheless able to give rational reasons for their faith in God. The Austrian philosopher Ludwig Wittgenstein (1889–1951) made this point clearly in his Culture and Value:
A proof of God's existence ought really to be something by means of which one could convince oneself that God exists. But I think that what believers who have furnished such proofs have wanted to do is to give their “belief” an intellectual analysis and foundation, although they themselves would never have come to believe as a result of such proofs.
So is it possible to “prove” God's existence? Or is proof something that is limited to mathematics and logic? Although many modern writers – such as Baruch Spinoza (1632–77) and René Descartes (1596–1650) – held that this kind of belief should be proved by clear and necessary reasons, postmodern philosophers – such as Wittgenstein – take the view that such beliefs must be seen as “fiduciary” (things that we believe, or regard as trustworthy). Why? Because, in the end, they rest upon commitments whose truth must be assumed and cannot be demonstrated.
Although discussion of the existence of God goes back to the classical period, the classic exploration of such questions, to which all modern discussion makes reference, is to be found in the Middle Ages. In particular, discussion of “proofs” of the existence of God generally take statements made by Anselm of Canterbury (c.1033–1109) in the eleventh century, and Thomas Aquinas in the thirteenth century, as their starting points. Anselm developed what has come to be known as “the ontological argument” for the existence of God. Aquinas developed the “Five Ways,” arguing from the effects of nature to their cause in God its creator. We shall consider these two categories of arguments individually, before moving on to consider some more recent discussions of the theme.
The Ontological Argument of Anselm of Canterbury (c.1033–1109)
Anselm of Canterbury was born in Italy. He migrated to Normandy in 1059 and entered the famous monastery of Bec, becoming its prior in 1063 and its abbot in 1078. In 1093, he moved to England, having been appointed archbishop of Canterbury. He is chiefly noted for his strong defense of the intellectual foundations of Christianity, and is especially associated with the “ontological argument” for the existence of God. This ontological argument was first set out in his Proslogion, a work which dates from 1079. (The term “ontological” refers to the branch of philosophy which deals with the notion of “being.”) It is important to realize that Anselm himself does not refer to his discussion as an “ontological” argument; in fact, he does not really consider it even to be an argment. The Proslogion is really a work of meditation, not of logical argument, in which Anselm reflects on how self-evident the idea of God has become to him, and what the implications of this might be.
In the Proslogion, Anselm offers a definition of God as “that than which no greater thing can be conceived.” So what are the implications of this? Anselm argues that, if someone agrees that God is indeed “that than which no greater thing can be conceived” and then argues that there is no God, there is a contradiction. Why? Because we can conceive of something still greater than a nonexistent God – namely, a God who exists.
God is thus defined as “that than which nothing greater can be conceived.” Now, the idea of such a being is one thing; the reality is another. Thinking of a hundred-dollar bill is quite different from having a hundred-dollar bill in your hands – and much less satisfying, as well! Anselm's point is this: the idea of something is inferior to the reality. So the idea of God as “that than which nothing greater can be conceived” contains a contradiction – because the reality of God would be superior to this idea. In other words, if this definition of God is correct, and exists in the human mind, then the corresponding reality must also exist.
It may be helpful to set out Anselm's argument in a series of numbered steps, so that each individual stage in the discussion can be appreciated.
Anselm expresses these points as follows, in a passage which has been studied intently (and, it must be said, also inconclusively) down the centuries:
This [definition of God] is indeed so true that it cannot be thought of as not being true. For it is quite possible to think of something whose nonexistence cannot be thought of. This must be greater than something whose nonexistence can be thought of. So if this thing (than which no greater thing can be thought) can be thought of as not existing, then, that very thing than which a greater thing cannot be thought is not that than which a greater cannot be thought. This is a contradiction. So it is true that there exists something than which nothing greater can be thought, that it cannot be thought of as not existing. And you are this thing, O Lord our God!
One obvious difficulty with this argument is that it is open to parody. Parallel arguments purporting to prove the existence of any perfect thing at all can be constructed. The most famous of these responses came from an eleventh-century Benedictine monk, Gaunilo of Marmoutiers, and is generally known as “A Reply on Behalf of the Fool” (an allusion to Psalm 14: 1, cited by Anselm: “The fool says in his heart that there is no God”). There is, according to Gaunilo, an obvious logical weakness in Anselm's “argument” (although, as we noted earlier, Anselm does not really regard it as an argument in the first place). Imagine, Gaunilo suggests, an island, so lovely that a more perfect island cannot be conceived. By the same argument, Gaunilo suggests, that island must exist, in that the reality of the island is necessarily more perfect that the mere idea. Gaunilo sets out his objections as follows:
People say that somewhere in the ocean there is an island which, because of the difficulty (or rather the impossibility) of finding that which does not exist, some have called the “Lost Island.” And we are told that it is blessed with all manner of priceless riches and delights in abundance, far more than the Happy Isles, and, having no owner or inhabitant, it is superior in every respect in the abundance of its riches to all those other lands that are inhabited by people. Now, if someone were to tell me about this, I shall easily understand what is said, since there is nothing difficult about it. But if I am then told, as though it were a direct consequence of this: “You cannot any more doubt that this island that is more excellent than all other lands truly exists somewhere in reality than you can doubt that it is in your mind; and since it is more excellent to exist not just in your mind but in reality as well, therefore it must exist.”
The response offered by Gaunilo is widely regarded as exposing a potentially serious weakness in Anselm's argument. In much the same way, we might argue that the idea of a hundred-dollar bill seems, according to Anselm, to imply that we have such a bill in our hands. The mere idea of something – whether a perfect island or God – thus does not guarantee its existence.
Anselm, however, is not so easily dismissed. Part of his argument is that it is an essential part of the definition of God that he is “that than which nothing greater can be conceived.” God therefore belongs to a category totally different from islands or dollar bills. It is part of the nature of God to transcend everything else. Once the believer has come to understand what the word “God” means, God really does exist for him or her. This is the intention of Anselm's meditation in the Proslogion: to reflect on how the Christian understanding of the nature of God reinforces belief in his reality. The “argument” does not really have force outside this context of faith, and Anselm never intended it to be used in this general philosophical manner.
Furthermore, Anselm argued that Gaunilo had not entirely understood him. The argument which he set out in the Proslogion did not involve the idea that there is a being that is, as a matter of fact, greater than any other being; rather, Anselm had argued for a being so great that a greater one could not even be conceived. The argument continues, and it remains a disputed question to this day whether Anselm's argument has a genuine basis.
Modern discussion of the argument has been influenced by the German philosopher Immanuel Kant, widely agreed to be the founder of modern critical philosophy. Kant was born in the German town of Königsberg (now the Russian city of Kaliningrad) in 1724 and was educated at the local university, where he became professor of logic and metaphysics. His major writings include the Critique of Pure Reason (1781), Critique of Practical Reason (1788), and Religion within the Bounds of Reason Alone (1793). Kant offered a major critique of the ontological argument for the existence of God, the central thesis of which takes the following form.
Kant insists that “existence is not a predicate.” Anselm's ontological argument improperly treats existence as some kind of property that things either possess or lack. According to Kant, to say that a thing “exists” is not to attribute existence to that thing but to say that this thing is exemplified in the world. As a result, being able to conceive the idea of God does not necessarily lead to the further idea “God exists.” Kant uses an analogy of a hundred dollars to make more or less the same point made earlier by Gaunilo with his image of the “ideal island”: conceiving an idea does not imply that its object necessarily exists. Kant makes this point as follows:
Now “Being” is clearly not a genuine predicate; that is, it is not a concept of something which could be added to the concept of a thing. It is merely the positing of a thing, or of certain determinations, as existing in themselves. Logically, it is merely the copula of a judgment. The proposition “God is omnipotent” contains two concepts, each of which has its object – God and omnipotence. The little word “is” adds no new predicate, but only serves to posit the predicate in its relation to the subject. Now if we take the subject (God) with all its predicates (among which is omnipotence), and say “God exists,” or “There is a God,” we do not attach any new predicate to the concept of God; we merely posit the subject in itself with all its predicates.
This line of argument had considerable influence within Christian theology, especially in the field of apologetics. Anselm's argument, however, continues to find its supporters, and remains an important stimulus to the contemporary debate about the validity and utility of arguments for the existence of God. For example, Alvin Plantinga (born 1932) and others have restated the argument in a manner which emphasizes the internal consistency of the existence of God:
Our verdict on these reformulated versions of St. Anselm's argument must be as follows. They cannot, perhaps, be said to prove or establish their conclusion. But since it is rational to accept their central premise, they do show that it is rational to accept that conclusion.
The “Five Ways” of Thomas Aquinas (c.1225–74)
Thomas Aquinas was probably the most famous and influential theologian of the Middle Ages. Born in Italy, he achieved his fame through his teaching and writing at the University of Paris and other northern universities. His fame rests chiefly on his Summa theologiae, composed toward the end of his life and not totally finished at the time of his death. However, he also wrote many other significant works, particularly the Summa contra Gentiles (“Summary against the Gentiles”), which represents a major statement of the rationality of the Christian faith, and especially the existence of God. Aquinas believed that it was entirely proper to identify pointers toward the existence of God, drawn from general human experience of the world. His “Five Ways” represent five lines of argument in support of the existence of God, each of which draws on some aspect of the world which “points” to the existence of its creator.
So what kinds of pointers does Aquinas identify? The basic line of thought guiding Aquinas is that the world mirrors God, as its creator – an idea which is given more formal expression in his doctrine of the “analogy of being.” Just as an artist might sign a painting to identify it as his or her handiwork, so God has stamped a divine “signature” upon the creation. What we observe in the world – for example, its signs of ordering – can be explained on the basis of the existence of God as its creator. God is both its first cause and its designer. God both brought the world into existence and impressed the divine image and likeness upon it.
So where might we look in creation to find evidence for the existence of God? Aquinas argues that the ordering of the world is the most convincing evidence of God's existence and wisdom. This basic assumption underlies each of the “Five Ways,” although it is of particular importance in the case of the argument often referred to as the “argument from design” or the “teleological argument.” We shall consider each of these “ways” individually, before focusing on two later in this chapter.
The first way begins from the observation that things in the world are in motion or change. The world is not static, but dynamic. Examples of this are easy to list. Rain falls from the sky. Stones roll down valleys. The earth revolves around the sun (a fact, incidentally, unknown to Aquinas). This, the first of Aquinas's arguments, is normally referred to as the “argument from motion”; however, it is clear that the “movement” in question is actually understood in more general terms, so that the term“change” is more appropriate as a translation at points.
Figure 8.3 Thomas Aquinas (c.1225–74).
Source: © 2015. Copyright The National Gallery, London/Scala, Florence.
So how did nature come to be in motion? Why is it changing? Why is it not static? Aquinas argues that everything that moves is moved by something else. For every motion, there is a cause. Things do not just move – they are moved by something else. Now each cause of motion must itself have a cause. And that cause must have a cause as well. And so Aquinas argues that there is a whole series of causes of motion lying behind the world as we know it. Now, since there cannot be an infinite number of these causes, Aquinas argues, there must be a single cause right at the origin of the series. From this original cause of motion, all other motion is ultimately derived. This is the origin of the great chain of causality that we see reflected in the way the world behaves. From the fact that things are in motion, Aquinas thus argues for the existence of a single, original cause of all this motion – and this, he concludes, is none other than God.
The existence of God can be proved in five ways. The first and most obvious proof is the argument from change. It is clearly the case that some things in this world are in the process of changing. Now everything that is in the process of being changed is changed by something else. [...] If, then, whatever is changing it is itself changed, this also must be changed by something else, and this in turn by something else again. But this cannot go on forever, since there would then be no first cause to this process of change, and consequently no other agent of change, because secondary things which change cannot change unless they are changed by a first cause, in the same way as a stick cannot move unless it is moved by the hand. We are therefore bound to arrive at a first cause of change which is not changed by anything, and everyone understands that this is God.
Once more, it may be helpful to summarize this argument as a series of brief statements, so that its basic structure is clearer.
The second way begins from the idea of causation. In other words, Aquinas notes the existence of causes and effects in the world. One event (the effect) is explained by the influence of another (the cause). The idea of motion, which we looked at briefly above, is a good example of this cause-and-effect sequence. Using a line of reasoning similar to that used above, Aquinas thus argues thatall effects may be traced back to a single original cause – which is God.
The third way concerns the existence of contingent beings. In other words, the world contains beings (such as human beings) which are not there as a matter of necessity. Aquinas contrasts this type of being with a necessary being (one who is there as a matter of necessity). While God is a necessary being, Aquinas argues that humans are contingent beings. The fact that we are here needs explanation. Why are we here? What happened to bring us into existence? Aquinas argues that a being comes into existence because something which already exists brought it into being. In other words, our existence is caused by another being. We are the effects of a series of causation. Tracing this series back to its origin, Aquinas declares that this original cause of being can only be someone whose existence is necessary – in other words, God.
The fourth way begins from human values, such as truth, goodness, and nobility. Where do these values come from? What causes them? Aquinas argues that there must be something which is in itself true, good, and noble, and that this brings into being our ideas of truth, goodness, and nobility. The origin of these ideas, Aquinas suggests, is God, who is their original cause.
The fifth, and final, way is often referred to as “the teleological argument” or the “argument from design.” Aquinas notes that the world shows obvious traces of intelligent design. Natural processes and objects seem to be adapted with certain definite objectives in mind. They seem to have a purpose. They seem to have been designed. But things don't design themselves: they are caused and designed by someone or something else. Arguing from this observation, Aquinas concludes that the source of this natural ordering must be conceded to be God.
Most of Aquinas's arguments are rather similar in terms of their structure. Each depends on tracing a causal sequence back to its single origin, and identifying this with God. A number of criticisms of the “Five Ways” were made by Aquinas's critics during the Middle Ages, such as Duns Scotus (1266–1308) and William of Ockham (c.1285–1347). The following are especially important.
These, then, are some of the classic arguments that have been developed and used within the philosophy of religion. So how have these medieval arguments been extended in more recent times? In what follows, we shall look briefly at some modern restatements.
The Kalam Argument
The argument that we shall refer to as the kalam argument derives its name from an Arabic school of philosophy which flourished in the early Middle Ages. The mutakallimun (as the practitioners of the kalam approach were known) developed an argument for the existence of God which stressedthe importance of causality. Some scholars regard this as a variant of the cosmological argument, already set out above. However, others regard it as having distinct features, meriting its treatment as an independent and distinct approach. The basic structure of the kalam argument can be set out as four propositions:
The structure of the argument is clear, and its implications need little in the way of further development. If the existence of something can be said to have begun, it follows – so it is argued – that it must have a cause. If this type of argument is linked with the idea of a Big Bang, its relevance for our discussion will be clear. Modern cosmology strongly suggests that the universe had a beginning. If the universe began to exist at a certain time, it must have had a cause. And what cause could there be other than God? Readers will note that there are some parallels between the basic contours of this argument and Aquinas's “Five Ways,” as discussed above.
This form of the kalam argument has been widely debated in recent years. One of its most significant defenders has been William Lane Craig (born 1949), who set out its main features as follows:
Since everything that begins to exist has a cause of its existence, and since the universe began to exist, we conclude, therefore, the universe has a cause of its existence. [...] Transcending the entire universe there exists a cause which has brought the universe into being.
Debate over the argument has centered on three questions:
It will be clear that the traditional kalam argument has been given a new lease of life by the Big Bang theory of the origins of the universe, which became of especial importance in the late twentieth century. However, the philosophical issues which are raised are likely to remain disputed. A similar debate focuses on the question of whether the universe can be said to be “designed,” and we shall consider this issue in what follows.
A Classic Argument From Design: William Paley (1743–1805)
The “argument from design” – also known as the “teleological argument” – is among the most widely discussed of the philosophical arguments for the existence of God. As we saw above, it is stated by Thomas Aquinas as the fifth of his “Five Ways.” Aquinas argues that there exist clear signs of design within the natural order. Things do not simply exist; they appear to have been designed with some form of purpose in mind. The term “teleological”(meaning “directed toward some goal”) is widely used to indicate this apparently goal-directed aspect of nature.
It is this aspect of nature that has often been discussed in relation to the natural sciences. The orderliness of nature – evident, for example, in the laws of nature – seems to be a sign that nature has been “designed” for some purpose. How else, it is argued, can this order be explained? It is for this reason that naturalist approaches to science, especially those that argue that matter possesses an intrinsic capacity to organize itself, are seen as such a threat by some modern Christian apologists.
It is widely agreed that the most significant contribution to the classic “argument from design” comes from the English theologian and natural philosopher William Paley (1743–1805). His Natural Theology; or Evidences of the Existence and Attributes of the Deity, Collected from the Appearances of Nature (1802) had a profound influence on popular English religious thought in the first half of the nineteenth century, and is known to have been read by Charles Darwin. Paley was deeply impressed by the discovery by Sir Isaac Newton (1643–1727) of the regularity of nature, especially in relation to the area usually known as “celestial mechanics.” It was clear that the entire universe could be thought of as a complex mechanism, operating according to regular and understandable principles. For Paley, the Newtonian image of the world as a mechanism immediately suggested the metaphor of a clock or watch, raising the question of who constructed the intricate mechanism which was so evidently displayed in the functioning of the world.
One of Paley's most significant arguments is that mechanism implies “contrivance.” Writing against the backdrop of the emerging Industrial Revolution, Paley sought to exploit the apologetic potential of the growing interest in machinery – such as “watches, telescopes, stocking-mills, steam engines” – within England's literate classes. Paley argues that only someone who is mad would suggest that such complex mechanical technology came into being by purposeless chance.
Mechanism presupposes contrivance – that is to say, a sense of purpose and an ability to design and fabricate. Both the human body in particular and the world in general are to be seen as mechanisms which have been designed and constructed in such a manner as to achieve harmony of both means and ends. The world, Paley argues, may therefore be compared to a watch – to something that has clearly been constructed with a specific purpose in mind.
The opening paragraphs of Paley's Natural Theology are well known, mainly on account of their image of God as creator. God is a watchmaker; nature is a watch.
In crossing a heath, suppose I pitched my foot against a stone, and were asked how the stone came to be there. I might possibly answer, that for any thing I knew to the contrary it had lain there for ever; nor would it, perhaps, be very easy to show the absurdity of this answer. But suppose I had found a watch upon the ground, and it should be inquired how the watch happened to be in that place. I should hardly think of the answer which I had before given, that for any thing I knew the watch might have always been there. Yet why should this answer not serve for the watch as well as for the stone; why is it not admissible in the second case as in the first? For this reason, and for no other, namely, that when we come to inspect the watch, we perceive – what we could not discover in the stone – that its several parts are framed and put together for a purpose, e.g. that they are so formed and adjusted as to produce motion, and that motion so regulated as to point out the hour of the day; that if the different parts had been differently shaped from what they are, or placed after any other manner or in any other order than that in which they are placed, either no motion at all would have been carried on in the machine, or none which would have answered the use that is now served by it.
Paley then offers a detailed description of the watch, noting in particular its container, coiled cylindrical spring, many interlocking wheels, and glass face. Having carried his readers along with this careful analysis, Paley turns to draw his critically important conclusion:
This mechanism being observed – it requires indeed an examination of the instrument, and perhaps some previous knowledge of the subject, to perceive and understand it; but being once, as we have said, observed and understood, the inference we think is inevitable, that the watch must have had a maker – that there must have existed, at some time and at some place or other, an artificer or artificers who formed it for the purpose which we find it actually to answer, who comprehended its construction and designed its use.
Paley's English prose is a little florid, reflecting the taste of the period. Nevertheless, the points that he is concerned to establish are clear. Most of Paley's imagery and analogies are borrowed from English academic writers of the late seventeenth or eighteenth centuries, including the famous image of the watch. Nevertheless, Paley succeeded in giving the argument and its associated images a high popular profile.
The essential point of Paley's argument is that nature includes a series of biological structures which are “contrived” – that is, constructed with a clear purpose in mind. “Every indication of contrivance, every manifestation of design, which existed in the watch, exists in the works of nature.” Indeed, Paley argues, the difference is that nature shows an even greater degree of contrivance than the watch.
Paley had an immense influence upon popular English attitudes to arguments for God's existence based on nature. The celebrated Bridgewater Treatises (1833–40) show his influence at many points, even if they develop an independent and rather more sophisticated approach at others. The noted antitheistic evolutionary biologist Richard Dawkins (born 1941) pays Paley a somewhat backhanded compliment in the title of one of his best-known antiteleological works, The Blind Watchmaker (1986). For Dawkins, the “watchmaker” whom Paley identified with God was none other than the blind and purposeless process of natural selection.
The concept of an “argument from design” had been subjected to criticism in the eighteenth century on a number of grounds by David Hume. The most significant of Hume's criticisms can be summarized as follows.
Having considered something of the classic arguments for God's existence, we must now move on to consider another classic theological debate: the nature of theological language. Can human words refer meaningfully to God?