The cosmological argument is less a particular argument than an argument type. It uses a general pattern of argumentation (logos) that makes an inference from particular alleged facts about the universe (cosmos) to the existence of a unique being, generally identified with or referred to as God. Among these initial facts are that particular beings or events in the universe are causally dependent or contingent, that the universe (as the totality of contingent things) is contingent in that it could have been other than it is, that the Big Conjunctive Contingent Fact possibly has an explanation, or that the universe came into being. From these facts philosophers infer deductively, inductively, or abductively by inference to the best explanation that a first or sustaining cause, a necessary being, an unmoved mover, or a personal being (God) exists that caused and/or sustains the universe. The cosmological argument is part of classical natural theology, whose goal is to provide evidence for the claim that God exists.
On the one hand, the argument arises from human curiosity as to why there is something rather than nothing or than something else. It invokes a concern for some full, complete, ultimate, or best explanation of what exists contingently. On the other hand, it raises intrinsically important philosophical questions about contingency and necessity, causation and explanation, part/whole relationships (mereology), infinity, sets, the nature of time, and the nature and origin of the universe. In what follows we will first sketch out a very brief history of the argument, note the two basic types of deductive cosmological arguments, and then provide a careful analysis of examples of each: first, two arguments from contingency, one based on a relatively strong version of the principle of sufficient reason and one based on a weak version of that principle; and second, an argument from the alleged fact that the universe had a beginning and the impossibility of an infinite temporal regress of causes. In the end we will consider an inductive version of the cosmological argument and what it is to be a necessary being
1. Historical Overview
Although in Western philosophy the earliest formulation of a version of the cosmological argument is found in Plato’s Laws, 893–96, the classical argument is firmly rooted in Aristotle’s Physics (VIII, 4–6) and Metaphysics (XII, 1–6). Islamic philosophy enriches the tradition, developing two types of arguments. Arabic philosophers (falasifa), such as Ibn Sina (c. 980–1037), developed the argument from contingency, which is taken up by Thomas Aquinas (1225–74) in his Summa Theologica (I,q.2,a.3) and his Summa Contra Gentiles (I, 13). Influenced by John Philoponus (5th c) (Davidson 1969) the mutakallimūm—theologians who used reason and argumentation to support their revealed Islamic beliefs—developed the temporal version of the argument from the impossibility of an infinite regress, now referred to as the kalām argument. For example, al-Ghāzāli (1058–1111) argued that everything that begins to exist requires a cause of its beginning. The world is composed of temporal phenomena preceded by other temporally-ordered phenomena. Since such a series of temporal phenomena cannot continue to infinity because an actual infinite is impossible, the world must have had a beginning and a cause of its existence, namely, God (Craig 1979: part 1). This version of the argument enters the medieval Christian tradition through Bonaventure (1221–74) in his Sentences (II Sent. D.1,p.1,a.1,q.2).
Enlightenment thinkers, such as Gottfried Wilhelm Leibniz and Samuel Clarke, reaffirmed the cosmological argument. Leibniz (1646–1716) appealed to a strengthened principle of sufficient reason, according to which “no fact can be real or existing and no statement true without a sufficient reason for its being so and not otherwise” (Monadology, §32). Leibniz uses the principle to argue that the sufficient reason for the “series of things comprehended in the universe of creatures” (§36) must exist outside this series of contingencies and is found in a necessary being that we call God. The principle of sufficient reason is likewise employed by Samuel Clarke in his cosmological argument (Rowe 1975: chap. 2).
Although the cosmological argument does not figure prominently in Asian philosophy, a very abbreviated version of it, proceeding from dependence, can be found in Udayana’s Nyāyakusumāñjali I,4. In general, philosophers in the Nyāya tradition argue that since the universe has parts that come into existence at one occasion and not another, it must have a cause. We could admit an infinite regress of causes if we had evidence for such, but lacking such evidence, God must exist as the non-dependent cause. Many of the objections to the argument contend that God is an inappropriate cause because of God’s nature. For example, since God is immobile and has no body, he cannot properly be said to cause anything. The Naiyāyikas reply that God could assume a body at certain times, and in any case, God need not create in the same way humans do (Potter 1977: 100–07).
The cosmological argument came under serious assault in the 18th century, first by David Hume and then by Immanuel Kant. Hume (1748) attacks both the view of causation presupposed in the argument (that causation is an objective, productive, necessary power relation that holds between two things) and the Causal Principle—every contingent being has a cause of its existence—that lies at the heart of the argument. Kant contends that the cosmological argument, in identifying the necessary being, relies on the ontological argument, which in turn is suspect. We will return to these criticisms below.
Both theists and nontheists in the last part of the 20th century and the first part of the 21st century generally have shown a healthy skepticism about the argument. Alvin Plantinga concludes “that this piece of natural theology is ineffective” (1967: chap. 1). Richard Gale contends, in Kantian fashion, that since the conclusion of all versions of the cosmological argument invokes an impossibility, no cosmological arguments can provide examples of sound reasoning (1991: chap. 7). (However, Gale seems to have changed his mind and in recent writings proposed and defended his own version of the cosmological argument, which we will consider below.) Similarly, Michael Martin (1990: chap. 4), John Mackie (1982: chap. 5), Quentin Smith (Craig and Smith 1993), Bede Rundle (2004), Wes Morriston (2000, 2002, 2003, 2010), and Graham Oppy (2006: chap. 3) reason that no current version of the cosmological argument is sound. Yet dissenting voices can be heard. Robert Koons (1997) employs mereology and modal and nonmonotonic logic in taking a “new look” at the argument from contingency. In his widely discussed writings William Lane Craig marshals multidisciplinary evidence for the truth of the premises found in the kalām argument. Richard Gale and Alexander Pruss propose a new version based on a so-called weak principle of sufficient reason that leads to a finite God that is not omnibenevolent, and Richard Swinburne, though rejecting deductive versions of the cosmological argument, proposes an inductive argument that is part of a larger cumulative case for God’s existence.
There is quite a chance that if there is a God he will make something of the finitude and complexity of a universe. It is very unlikely that a universe would exist uncaused, but rather more likely that God would exist uncaused. The existence of the universe…can be made comprehensible if we suppose that it is brought about by God. (1979: 131–32)
In short, contemporary philosophers continue to contribute increasingly detailed and complex arguments on both sides of the debate.