Thinking about God brings together our powers of speculation, our deepest values, and our greatest hopes and fears. It is therefore fertile philosophical territory. Some of the arguments for belief in God are theoretical in that they appeal to our reason. Other arguments are practical in that they invoke God to make sense of some of our practices, such as morality. In this chapter, we will review the most influential theoretical arguments for God’s existence: the teleological, the cosmological, and the ontological arguments. The former two try to show God’s existence using tools familiar from ordinary empirical reasoning; God is a hypothesis to be proven in much the same way as we prove more mundane hypotheses, marshalling the evidence as best we can. Just as a one might see a puddle and infer that it has been raining recently, one might observe certain other features of the world and infer God as the best (or only) explanation of them. The latter argument is more closely akin to mathematics and conceptual analysis; just as one might reflect on the concept of a triangle and ascertain that its internal angles must add up to 180°, one might reflect on the concept of God and ascertain that he must exist. Lastly, we will introduce the suggestion that it is legitimate to believe in God without providing arguments at all: that belief in God is more properly a cornerstone for our thinking, than a mere conclusion of some argument. Each of these arguments have been articulated in myriad ways, so we will focus our attention on some of the most influential versions.
The Teleological Argument
“Telos” being Greek for “purpose” or “goal,” the teleological argument takes as its starting point the appearance of purpose or design in the world. If there is design, there must be a designer. This thought is an ancient and cross-cultural one, appearing in classical Hindu thought (Brown 2008) and in the Psalms: “The heavens declare the glory of the Lord; and the firmament sheweth his handiwork” (Psalm 19:1). An influential formulation comes from William Paley (1743-1805). In Natural Theology, Paley offers numerous instances of apparent design, focusing primarily on biological organisms. Paley argues that organisms are analogous to human-created artifacts in that they involve a complex arrangement of parts that serve some useful function, where even slight alterations in the complex arrangement would mean that the useful function was no longer served. An eye, like a watch, evidently serves a useful function. The function is only achieved by a very complex arrangement of parts, which in turn serve various sub-functions, all ordered towards the higher function. Had this arrangement been different in any minute detail, the eye would not successfully serve its higher function. To explain this feature of the eye, we should, on an analogy with the watch, refer to a designing mind’s activity, rather than the blind play of causal forces. As we are to the watch, so God is to the eye. To Paley, God is a powerful and simple hypothesis that must be invoked to explain the design resplendent in nature (Paley 1802).
Formulations of the teleological argument like Paley’s have been subjected to searching criticisms, not least by David Hume (1711-1776). In his fabulously written Dialogues Concerning Natural Religion, Hume questions how close the analogy of design really is. For example, we produce artifacts by acting on pre-existing materials, but God is supposed to create from nothing. Most artifacts have a purpose that is evident to us, but God’s purpose in having created this or that creature, or the world at all, is unclear. We have seen artifacts being manufactured on many occasions, but never an organism, or the world. Even granting unequivocally that there is design in the world, we would not be justified in inferring God to explain it. Hume notes that artifacts are usually the result of collaboration by many people. Nor is there any connection between the qualities of an artifact and the qualities of its designer; one need not be a giant to build a skyscraper or be beautiful to make a beautiful painting. So, the design in the world need not be the design of one being, or an especially exalted being. Rather, the evidence of design is equally consistent with the hypothesis of polytheism (Hume 1779). Perhaps as devastating for Paley’s formulation, Charles Darwin’s (1809-1882) theory of evolution by natural selection is widely taken to show that the complex arrangement of parts and the functions of the parts of organisms can be accounted for without reference to a designing mind. The appearance of design is merely appearance; the analogy between artifacts and organisms is a misleading one. God is an obsolete hypothesis so far as the explanation of these phenomena are concerned. A distinct minority, the proponents of “Intelligent Design” contest this claim by offering examples of biological phenomena that supposedly cannot be explained by Darwinian evolution (Behe 1996). Barbara Forest argues that “Intelligent Design” theories lack a serious methodology, given that they invoke miraculous intervention in an unprincipled way to explain various phenomena (Forrest 2011).
However, teleological arguments continue to thrive in other forms. One line of thinking is the fine-tuning argument. Our universe seems to be governed by a batch of laws of nature—e.g. gravity, the strong nuclear force. It seems possible that these laws of nature could have been different in an unfathomable number of ways—e.g. we can conceive gravity as a billion times stronger than it is, or a billion times weaker. It seems that most of the ways that the laws of nature could have been would not allow for embodied moral agents (or, more broadly, life) by not allowing for the emergence of complex matter. Now, arguably God is a being who wishes there to be embodied moral agents. So, if there is a God, this predicts a universe with laws of nature that allow for the emergence of embodied moral agents, laws that are finely-tuned for such a purpose. By contrast, if there is no God there is no particular reason to predict that the laws of nature will be like this. Our universe seems to be one with laws that allow for embodied moral agents. Therefore, our universe is more consistent with the theistic hypothesis, so probably God exists. Finally, putting aside the fine-tuning of the physical laws we enjoy, Richard Swinburne contends that the fact that our universe is governed by laws at all, rather than being chaotic, is something that demands a design-based explanation (Swinburne 2004).
Whether such arguments really identify phenomena that stand in need of a special explanation, and whether the explanations they offer are vulnerable to being supplanted by non-theistic alternatives, is a matter of ongoing debate.
- What is the value of arguments by analogy, such as Paley’s? Do they give new information, or just highlight information you already had, or can they even be misleading?
- Suppose you were convinced that our universe is in fact fine-tuned. What, if anything, would you be entitled to infer about the nature of the fine-tuner(s)?
- Many have thought that Darwinian evolution thoroughly undermines the view that biological phenomena are designed by God. Is there a consistent way of holding both views? Supposing there is, would the hypothesis of a designer-God still be a necessary part of the explanation of the biological phenomena, or a somewhat ornamental addition?
The Cosmological Argument
“Cosmos” being Greek for “world,” the cosmological argument suggests God as the only adequate hypothesis in explaining why there is something rather than nothing. Cosmological arguments go back at least as far as Plato (428-348 BCE), with influential formulations being offered by Thomas Aquinas (1225-1274) and Gottfried Leibniz (1646-1716). One influential formulation comes from Samuel Clarke (1675-1729).
In A Demonstration of the Being and Attributes of God, Clarke argues for the conclusion that God is the reason for the universe’s existence by showing the bankruptcy of the alternatives. Something must have existed from eternity, Clarke reasons, since to suppose otherwise would be to suppose that something arose from nothing, which is absurd. Further, this eternal something must be independent of the universe. Think of a sapling tree. Like every individual thing in the universe its existence is contingent—it could fail to exist—as demonstrated by the fact that it once did not exist and by the fact that it is susceptible to change and destruction. Therefore, its reason for existing must be sought outside it; if we seek the reason why the sapling exists we must refer to its parent tree, the soil, the sun, the air. But if everything in the universe is contingent, then so is the universe itself, and its reason for existing must be sought outside it. Even if the universe had no beginning in time, and we could trace the sapling’s reason for existing backward indefinitely, we would still need to explain why there was this endless succession of contingent beings rather than nothing. Think of “reason for existing” as being like the parcel in the children’s game “pass the parcel.”1 Even supposing an infinite number of players, or a circle of players passing the parcel for an eternity, if every player must receive the parcel from another (like a contingent being receives its reason for existing from another), then we would still face the question where the players got the parcel in the first place. Lastly, the being outside the universe must have a necessary existence; that is, it must contain the reason for its existence within itself, such that it could not fail to exist. By the difficulties attending all the alternatives, we are driven to accept that not all beings are contingent; our search for reasons for existing must reach its terminus in a necessary being, God. Clarke admits that the notion of necessary existence is difficult to conceive, since all the beings we encounter are contingent, but holds that it is the only adequate hypothesis in explaining why there is something (Clarke 1705).
Clarke’s cosmological argument was also criticized by Hume in his Dialogues Concerning Natural Religion. Hume questions why the universe itself may not be the necessary being. Clarke’s reason for rejecting this idea was that everything in the universe is contingent. But, Hume notes, Clarke is committing the fallacy of composition. A flock may be composed of sheep destined for slaughter, but this does not prove that the flock itself is destined for slaughter. Likewise, perhaps the universe’s existence is necessary despite the contingency of every individual thing in it, a thought which is lent some credibility by the physical principle that matter can neither be created nor destroyed. Raising further havoc, Hume questions whether there can even be such a thing as a necessary being. It seems to be a feature of claims which are necessary—like “2+2=4” or “a nephrologist is a physician of the kidneys”—that their contraries cannot be conceived without contradiction, as with “2+2=5.” But we seem able to conceive any being’s nonexistence without contradiction; just as I can coherently conceive of the sapling’s nonexistence, I can coherently conceive of God’s nonexistence (as shown by the fact that we feel the need to debate God’s existence).
Another issue is that Clarke’s cosmological argument, like many other formulations, invokes the “principle of sufficient reason,” or the idea that every state of affairs has a reason why it is so and not otherwise. This seems to be a principle that we make thorough use of from early childhood in endlessly asking “why?” and expecting that there must be answers. Because of this principle, we insist that the universe must have a reason for its existence, rather than allowing that the universe is an unaccountable “brute fact.” But why should we accept the principle of sufficient reason? It does not seem to be a necessary truth or something we can infer from experience (Pruss 2006).
A quite different version of the cosmological argument is presented by William Lane Craig, drawing upon the Islamic philosophers of the 9th-12th centuries such as al-Ghazali (1058-1111), called the kalām cosmological argument. Craig argues that whatever begins to exist has a cause, that the universe began to exist, and that God must be invoked as its cause. Why believe that the universe began to exist? For one thing, it seems that the universe cannot have an infinite temporal duration since the successive addition of finites cannot add up to something infinite. Just as one cannot “count to infinity,” the compounding of the moments that pass in time could not ever add up to an infinite temporal duration. For another, if we make the supposition that the universe has an infinite temporal duration various absurdities arise. Sundays are a subset (one-seventh) of all the days that have ever occurred. A very bored deity would count out six non-Sundays for every Sunday. But if the universe has an infinite temporal duration, then an infinite number of Sundays have occurred. And an infinite number of non-Sundays have occurred. Therefore, the subset is equal in magnitude to the set—an absurdity. So, the universe began to exist. Notice that Craig’s argument avoids referring to necessary beings, or the principle of sufficient reason; Craig’s argument requires only that if something begins to exist, then it has a cause. Supporters of the kalām cosmological argument may also cite scientific evidence to support the idea that the universe began to exist, for instance the Big Bang theory or the idea that if the universe had an infinite temporal duration, then entropy would guarantee that complex matter would not exist presently (Craig 1979).
One key question about Craig’s kalām cosmological argument is whether the cause of the universe must be something like our conception of God, a kind of personal agent. Craig, following al-Ghazali, suggests that the cause of the universe must be timeless, outside of time entirely. Physical causes bring about their effects, as it were, immediately. For example, an effect like the process of water freezing will begin to happen as soon as its cause, a sub-zero temperature, is present. So, if the cause of the universe is timeless and is a physical cause, we would expect the universe to have always existed. But as we have seen, that cannot be. So, the cause of the universe must be non-physical. Aside from physical causes, we sometimes explain effects as resulting from actions—we have the idea that personal agents bring about effects spontaneously as and when they will to do so, in a way that is different than and not entirely determined by physical causes. On this model, plausibly the cause of the universe is the action of a personal, but non-physical, agent. Others have objected, though, that it is difficult to make sense of the idea of a personal agent who acts but is also outside of time, and again that we are having to rely too heavily on our limited repertoire of concepts: for all we know, there might be causes that are neither like the physical nor like personal agency.
- It seems that the opponent of the cosmological argument can try to defuse it by denying that the universe has a reason for its existence, or a cause, or by denying the principle of sufficient reason. Are these unreasonable moves? Is there any claim or principle that it would be unreasonable to deny, if the alternative was the conclusion that God exists?
- In theory, could science one day prove that the universe did not begin to exist? What impact would such a finding have on Clarke’s cosmological argument? On Craig’s kalām cosmological argument?
- Is it reasonable to rely on our limited repertoire of concepts, as exemplified in the discussion about whether the cause of the universe is a personal agent? Should we be worried by the thought that reality may be stranger than we can conceive?
The Ontological Argument
“Ontos” being Greek for “being” or “existence,” the ontological argument is unusual in that it has no empirical premises at all; God is not called upon as an explanation for anything. Rather, God’s existence is proven by reflection on the concept of God. This is an extremely unfamiliar way of proceeding, since ordinarily we think that by analyzing the concept of something, we may discover the predicates that will be true of it if it exists, but not that it exists. For instance, if I have a child
- Pass the parcel is a parlour game in which a parcel containing a prize is passed around and around in a circle.