The Cosmological Argument for the Existence of God
Note: One of my duties in the various places where I teach is to show students how to write essays – something most young people are not nowadays taught to do. What I like to do in class is to choose a question at random, discuss possible approaches, and then dictate an answer one paragraph at a time. Some of these answers are very short. Some are just notes. Some amount to small dissertations. In this latter case, the students take turns at looking on-line for the information we decide is needed. It they cannot find it, I show them how to change the structure of what has already been written, or to strike out in a new direction.
It is a “writing masterclass” approach that makes use of my own strengths, and is often a welcome alternative to formal teaching. It fills up a long morning session. Everyone learns something, and the more attentive will improve their final grades by at least one step.
Here is an example of the finished product. Do not take it as a statement of personal opinion. It is an answer produced for a specific question, and it bears in mind what a possibly unknown examiner will appreciate, and what can be written to incorporate the sources found in class. SIG
PS – If anyone wants to engage my services as a teacher of these skills, please click on the image to the left. Though they are my niche subjects, Greek and Latin are not my exclusive focus as a teacher. I do much else besides.
(i) Outline the Key Concepts of the Cosmological Argument for the Existence of God (21)
The cosmological argument is most closely associated with the thirteenth-century philosopher Thomas Aquinas, who worked within the Aristotelian tradition, though similar lines of reasoning appear in later thinkers such as Leibniz and, in a modern form, William Lane Craig. Its central aim is to demonstrate the existence of God not by appeal to revelation, but by reasoning from experience—specifically, from the nature of the universe as we observe it.
At its most general level, the cosmological argument begins from the existence of the world and seeks to explain why it exists at all. It assumes that the universe is intelligible, ordered, and dependent, and that this dependence requires explanation. Aquinas presents several versions of the argument, traditionally summarised as the “Three Ways” relevant here: the argument from motion, the argument from causation, and the argument from contingency.
The first form of the argument is derived from Aristotle’s concept of motion, where “motion” is understood broadly as change. We observe that objects in the world undergo change: wood becomes hot when placed in a fire, water turns to steam when heated, and so forth. Aquinas argues that whatever is changed must be changed by something else, since nothing can be both in potentiality and actuality in the same respect at the same time. For example, wood is potentially hot but not actually hot until acted upon by fire.
From this, Aquinas constructs a chain of movers: each change is brought about by something already actual. However, he insists that this chain cannot regress infinitely. If there were no first mover, there would be no subsequent movers, and therefore no motion at all. Since motion clearly exists, there must be a first mover that itself is unmoved—something that initiates change without itself being changed. This unmoved mover is identified as God.
The second form of the argument proceeds in a similar manner, but focuses on efficient causation. In the world, we observe that events have causes. A billiard ball moves because it is struck by another; that ball moves because it was struck by a cue; the cue is wielded by a human being, whose existence depends on prior causes, and so on. Nothing can be the cause of itself, since this would require it to exist before it existed, which is logically impossible.
Again, Aquinas argues that an infinite regress of causes is impossible. If there were no first cause, there would be no intermediate causes and no effects. Since effects do exist, there must be a first cause that itself is uncaused. This uncaused cause is identified as God.
The third form of the argument is based on the distinction between contingency and necessity. A contingent being is one that does not have to exist; it comes into existence and passes out of existence. Everything we observe in the world appears to be contingent. Trees grow and die, buildings are constructed and decay, and human beings are born and eventually perish. It is therefore possible to imagine a time when none of these things existed.
Aquinas argues that if everything were contingent, then at some point nothing would have existed. If that were the case, nothing could ever have come into existence, since something cannot arise from nothing. Therefore, there must be at least one necessary being—a being that cannot not exist and whose existence is not dependent on anything else. This necessary being is said to be the ultimate explanation for the existence of all contingent things, and this being is identified as God.
Taken together, these arguments present God as the unmoved mover, the uncaused cause, and the necessary being. The cosmological argument claims that the existence of the universe requires an ultimate explanation, and that this explanation must lie outside the chain of motion, causation, and contingency. Infinite regress is rejected on the grounds that it would fail to provide a sufficient explanation for the existence of the world.
(ii) Comment on the Claim that the Cosmological Argument is Not Convincing (9)
From a broadly Humean perspective, the cosmological argument is unconvincing, not because its reasoning is formally invalid, but because its key assumptions go beyond what experience can justify.
Hume’s most fundamental objection concerns causation itself. The cosmological argument assumes that every event must have a cause and that this principle can be extended beyond experience to explain the existence of the universe as a whole. However, Hume argues that our belief in causation is not derived from reason but from habit. We observe that certain events regularly follow others, and we form an expectation that this pattern will continue. But we never perceive any necessary connection between cause and effect. The idea that everything must have a cause is therefore a psychological expectation, not a logically demonstrable truth. It is sufficient for practical life, but it cannot support a proof of the existence of a supreme being.
A further weakness lies in the move from parts to the whole. Even if every individual thing within the universe has a cause, it does not follow that the universe as a whole must have a cause. As Bertrand Russell later observed, this is like saying that because every member of a cricket team has a father, the team itself must have a father. The argument commits a fallacy of composition, extending a property of parts to the whole without justification.
The rejection of infinite regress is also questionable. Aquinas insists that an infinite chain of causes is impossible, but this claim is asserted rather than demonstrated. The appeal to logical difficulties—such as those illustrated by Hilbert’s Hotel—does not establish that infinity is impossible, only that it is difficult to conceive. As Hume would argue, the limits of our imagination do not determine the limits of reality. If it is permissible to posit an infinite God, it is not obvious why an infinite series of causes should be ruled out.
The argument from contingency is similarly vulnerable. It assumes that the existence of contingent beings requires a necessary being as an ultimate explanation. However, Hume challenges the idea that the universe requires such an explanation at all. It may simply be a brute fact. Our desire for explanation does not guarantee that an explanation exists. The universe may exist without any further reason, just as individual events occur without any discernible necessity beyond their regular occurrence.
Finally, even if the argument were successful in establishing a first cause or necessary being, it does not follow that this being possesses the characteristics traditionally associated with God. The argument does not demonstrate omnipotence, omniscience, or benevolence. It merely posits some kind of explanatory terminus. To identify this with the God of classical theism is an additional step that is not justified by the argument itself.
In conclusion, the cosmological argument is unconvincing from a Humean standpoint because it relies on assumptions about causation, necessity, and explanation that exceed the limits of experience. While it provides a structured attempt to explain the existence of the universe, it ultimately rests on principles that cannot be proven and therefore fails to establish the existence of God.