Cosmological Argument

The basic shape

The cosmological argument is not a single argument but a family. What unites them is a two-step pattern:

1. Empirical premise. Some feature of the world is identified — that things move, that things are caused, that things might not have existed, that the universe began. This is the "cosmological" part: the argument starts from the cosmos.
2. Regress-and-grounding step. The premise is extended back: each motion has a mover, each cause has a cause, each contingent thing has an explanation, each beginning has a beginner. The chain cannot regress infinitely (or can but doesn't suffice). Therefore the chain terminates in something that grounds itself — an unmoved mover, an uncaused cause, a necessary being, or a creator.

The conclusion of the argument is austere: a first cause, a necessary being, an unmoved mover. Theistic philosophers then add a "and this is what we call God" step (Aquinas's phrase) — a separate task of identifying the abstract terminus with the personal God of theism.

Aristotle's Unmoved Mover

The earliest version is Aristotle's, in Metaphysics XII (Book Lambda, c. 350 BCE). Aristotle observes that things in the cosmos move — including the heavens themselves, eternally rotating. Every motion requires a mover. If the chain of movers were infinite, there would be no ultimate source of motion, and so no motion at all. Therefore there must be an unmoved mover — something that causes motion without itself being moved.

Aristotle's unmoved mover is not a creator. It does not bring matter into being (matter is eternal, for Aristotle). It moves things by being the object of their desire — like a beloved who moves a lover without herself moving toward him. The unmoved mover is pure actuality, eternal, impersonal, and engaged solely in self-contemplation: "thought thinking itself." This is far from the Christian God, but the structural template — an eternal source that grounds finite causes — was what later theologians would inherit.

Aquinas's Five Ways (the first three)

Thomas Aquinas formulated the most famous Christian version in Summa Theologiae I.2.3 (c. 1265). Five "ways" are offered; the first three are cosmological in form, the fourth (degrees of perfection) is Platonic, and the fifth (governance of nature) is teleological.

First Way — From Motion. Things in the world are in motion. Whatever is moved is moved by another (a self-mover would have to be in act and potency in the same respect, which is impossible). The chain cannot regress to infinity, for then there would be no first mover and so no motion at all. Therefore there is a first unmoved mover, "and this everyone understands to be God."

Second Way — From Efficient Causation. In the world we observe a series of efficient causes. Nothing causes itself (for then it would have to exist before it existed). The series cannot regress to infinity, for an infinite series of efficient causes would have no first cause, and without a first cause there would be no intermediate or final cause. Therefore there is a first efficient cause, "to which everyone gives the name of God."

Third Way — From Contingency. Things in the world are contingent — they come to be and pass away. If everything were contingent, there would have been a time when nothing existed (since any contingent thing might not exist, given infinite time, all would simultaneously fail to exist). But then nothing would now exist, since nothing comes from nothing. Therefore not everything is contingent; there must be at least one necessary being. (This argument is logically dense and has been challenged on the move from "each is contingent" to "all are contingent at once." Modern formulations are tighter.)

The crucial Aquinas innovation is the distinction between per se (essential) and per accidens (accidental) causal series. Aquinas thought an infinite per accidens series — a chain stretching back in time — was metaphysically possible (he held this for Aristotelian reasons; he believed creation in time only on faith). What he ruled out was an infinite per se series, where each member depends simultaneously on its predecessor for its causal power. Like a chain of gears, where each gear can only turn because the one before it turns: with no first gear, none turns.

Leibniz and the Principle of Sufficient Reason

Leibniz, in The Principles of Nature and Grace (1714), gave the contingency argument its most ambitious form. His engine is the Principle of Sufficient Reason (PSR): for every fact, there is a sufficient reason why it is so and not otherwise. The argument:

1. The world exists. (premise)
2. The world's existence is contingent — it might not have existed.
3. By the PSR, there must be a sufficient reason why the world exists rather than not.
4. The reason cannot lie within the world, since the world is contingent (anything within it shares the contingency).
5. Therefore the reason lies outside the world, in a being that is its own reason — a necessary being.
6. This necessary being is God.

Leibniz's "Why is there something rather than nothing?" is a haunting question. Even those who reject the conclusion often grant that the question is intelligible. Critics target the PSR (Hume: not all facts have explanations; Hume's quantum-physics descendants: brute facts may exist) or the move from "outside the world" to "God" (Russell, Mackie: necessary being could be the world itself, or matter, or a multiverse).

The Kalam argument

The Kalam argument originated in medieval Islamic theology — kalām means "speech" or "scholastic theology." Its most influential developer was the 11th-century Persian theologian al-Ghazali (1058–1111), in The Incoherence of the Philosophers. The argument was largely dormant in Western philosophy until William Lane Craig revived it in The Kalām Cosmological Argument (1979). Its modern form:

1. Whatever begins to exist has a cause.
2. The universe began to exist.
3. Therefore the universe has a cause.

The argument is simple in form. Premise 1 is defended as a basic principle of reason and confirmed by all experience. Premise 2 is defended on two grounds: (a) philosophical arguments against the possibility of an actually infinite past (Hilbert's hotel paradoxes; the impossibility of traversing an infinite series); and (b) scientific evidence — the Big Bang cosmology, particularly the Borde-Guth-Vilenkin theorem (2003) which states that any universe undergoing average cosmic expansion must have had a beginning.

From the conclusion, Craig argues the cause must be timeless, spaceless, immaterial (since space, time, and matter come into being with the universe), enormously powerful, and personal (because only an agent could cause a temporal effect from a timeless state). This is the move to theism.

Critics: physicist Sean Carroll has disputed Craig's interpretation of BGV; quantum cosmology suggests events can be uncaused (premise 1 may not hold for quantum-scale events); the move from "personal" cause is contested.

Worked example: the Leibnizian argument formalized

Let W = "the world (the totality of contingent things)" and let R = "has a sufficient reason for its existence."

P1. ∀x (Cx → Rx)            (PSR for contingent things)
P2. CW                       (W is contingent)
P3. RW → ∃y (yRx ∧ ¬Cy)     (the reason for a contingent thing must lie in something non-contingent)
∴ ∃y (yRW ∧ ¬Cy)            (there exists a non-contingent being grounding W)

The argument is valid. Each step requires defense:

• P1 (PSR): contested. Hume rejects it; van Inwagen calls it implausible; Pruss and Koons defend modern versions.
• P2: most accept. The world could have been different; could have not existed.
• P3: contested. Why couldn't the reason for the contingent W lie in another contingent being? Answer (Pruss): an infinite chain of contingent reasons doesn't actually explain the chain itself. Counter (Hume): explaining each member is enough; explaining the whole is a confused demand.

The validity is uncontested; the soundness depends on defending all three premises against sustained attack.

Cosmological vs ontological vs teleological

	Cosmological	Ontological	Teleological
Type	A posteriori	A priori	A posteriori
Starting point	That anything exists	The concept of God	That nature shows order
Empirical input	Bare existence (or motion, beginning)	None	Specific features of nature
Strength of conclusion	Necessary being / first cause	Maximally great being	Intelligent designer
Classic proponent	Aristotle, Aquinas, Leibniz, Craig	Anselm, Descartes, Plantinga	Paley, Behe, Collins
Standard objection	Why must the chain end?	Existence is not a predicate	Hume on bad analogy; evolution
Distance to theism	Long (necessary being → personal God)	Short (built into definition)	Medium (designer → God)

The cosmological and teleological arguments are complementary in a sense: cosmological asks why the world exists at all; teleological asks why the world has the order it does. Some philosophers (Swinburne) treat them as cumulative — each shifts probability slightly, and together they shift it more.

Hume's objections

David Hume's Dialogues Concerning Natural Religion (1779, posthumous) is the canonical attack on natural theology. Through his characters Cleanthes (defender), Demea (cosmological proponent), and Philo (skeptic), Hume mounts several objections to the cosmological argument.

1. The fallacy of composition. Even if every part of the universe has a cause, it doesn't follow that the universe as a whole has a cause. Each Inuit has a mother; the Inuit people have no mother. Demanding a cause of the totality may simply be a confused demand.

2. The brute-fact alternative. "Why might not the material universe be the necessarily existent Being?" If something must exist necessarily, why not the universe itself? The argument moves from "something necessary exists" to "God exists" by a step that is unsupported.

3. The induction problem. Causation is, for Hume, a habit of mind formed by observed regularities, not a metaphysical necessity. We have no warrant to project the cause-effect pattern from middle-sized objects to the cosmos as a whole. Saying "the universe has a cause" extrapolates beyond all possible experience.

4. The under-determination of theism. Even granting a first cause, why think it is one rather than many, infinite rather than finite, perfect rather than flawed, conscious rather than impersonal, still existing rather than long since spent? The argument's conclusion is meager; the leap to the God of Christianity is a leap of inches, not of philosophy.

Hume's objections set the agenda for two centuries of debate. Bertrand Russell's famous radio debate with Frederick Copleston (1948) covered much of the same ground: Russell at one point declared, "The universe is just there, and that's all" — adopting Hume's brute-fact strategy.

Modern objections

J. L. Mackie, in The Miracle of Theism (1982), argues the PSR is unmotivated: there is no reason in advance to assume every fact has an explanation. Some explanations have to terminate; the question is just where. The theist places the termination at God; the naturalist at the universe. Neither side wins on logical grounds.

Quentin Smith argues from quantum mechanics that the universe could have come into being uncaused. Quantum events appear to occur without sufficient causes; if so, the cosmological premise that every beginning has a cause is empirically false.

Adolf Grünbaum argues the question "Why is there something rather than nothing?" is malformed. It presupposes that nothing is the natural default state requiring no explanation, while existence requires explanation. But why think nothingness is the default? Maybe existence is.

Graham Oppy, in Arguing About Gods (2006), provides perhaps the most thorough contemporary critique. Oppy argues that for every theistic cosmological argument, there is a parallel naturalistic argument that infers a non-divine necessary being (the universe, or its laws, or some abstract principle). Without independent reason to prefer the theistic terminus, the argument fails to favor theism over naturalism.

Family members

• Aristotle's Unmoved Mover (Metaphysics XII, c. 350 BCE) — eternal source of motion; impersonal.
• Avicenna's contingency argument (Metaphysics of the Healing, c. 1020) — distinguished necessary and possible existents; influenced Aquinas.
• al-Ghazali's Kalam argument (Incoherence of the Philosophers, 1095) — universe began, has a cause.
• Aquinas's first three Ways (Summa Theologiae I.2.3, c. 1265) — motion, causation, contingency.
• Leibniz's argument from contingency (1714) — PSR-driven; "Why is there something rather than nothing?"
• Samuel Clarke's argument (Demonstration, 1705) — modal version of contingency argument; influenced Hume.
• Craig's Kalam revival (1979) — Kalam plus Big Bang cosmology.
• Pruss's Leibnizian argument (2006) — modal contingency with strong PSR; contemporary defense.
• Koons's "new" cosmological argument (1997) — defended PSR via causal explanations of contingent facts.

Common confusions

• "It's the same as the ontological argument." No — they are opposite in method. The ontological argument is a priori (definition only). The cosmological is a posteriori (starts from existence).
• "It's been disproven by science." Misleading. The Kalam version has been challenged on quantum-cosmological grounds, but the contingency version is metaphysical and not directly addressed by physics. Physics itself takes the existence of laws and initial conditions for granted.
• "It commits the fallacy of composition." This is Hume's objection, and it's a serious one for some versions, but not all. Aquinas's per se series is not a composition fallacy; it's a structural claim about simultaneous dependence.
• "God needs a cause too." The traditional reply is that God is not a contingent being; the argument terminates at a being whose existence does not require external explanation. Whether the asymmetry is principled or arbitrary is the real question.
• "It proves the Christian God." No, even most defenders concede this. The argument concludes to a necessary being or first cause; identifying that with the God of theism requires further argument (revelation, Trinity, incarnation are not in the conclusion).
• "Aquinas argued for an infinite past." Aquinas held creation in time on faith but argued philosophy alone could not establish whether the universe had a temporal beginning. His Five Ways do not depend on the universe being finite in time — they target structural dependence, not temporal sequence.