Philosophy of Religion (booklet)

The Cosmological Argument

The cosmological argument is the argument that the existence of the world or universe is strong evidence for the existence of a God who created it. The existence of the universe, the argument claims, stands in need of explanation, and the only adequate explanation of its existence is that it was created by God.

Like most of the purported proofs of the existence of God, the cosmological argument exists in several forms. Two forms of the argument will be discussed here: the temporal, kalam cosmological argument (i.e. the first cause argument), and the modal “argument from contingency”.

The main distinguishing feature between these two arguments is the way in which they evade an initial objection to the argument. In order to explain what this objection is, and how the two arguments evade it, a simple, generic statement of the cosmological argument will be necessary. This statement is as follows:

The Simple Cosmological Argument

(1) Everything that exists has a cause of its existence.

(2) The universe exists.

Therefore:

(3) The universe has a cause of its existence.

(4) If the universe has a cause of its existence, then that cause is God.

Therefore:

(5) God exists.

This argument is subject to a simple objection, which arises in the form of the question “Does God have a cause of his existence?”

If, on the one hand, God were thought to have a cause of his existence, then positing the existence of God in order to explain the existence of the universe wouldn’t get us anywhere. Without God there would be one entity the existence of which we could not explain, namely the universe; with God there would be one entity the existence of which we could not explain, namely God. Positing the existence of God, then, would raise as many problems as it solved, and so the cosmological argument would leave us in no better position than it found us.

If, on the other hand, God were thought not to have a cause of his existence, i.e. if God were thought to be an uncaused being, then this too would raise difficulties for the simple cosmological argument. For if God were an uncaused being then his existence would be a counterexample to premise (1). If God exists but does not have a cause of his existence then premise (1) is false, in which case the simple cosmological argument is unsound. If premise (1) is false, i.e. if some things that exist do not have a cause, then the cosmological argument might be resisted on the ground that the universe itself might be such a thing. The existence of an uncaused God would thus render the simple cosmological argument unsound, and so useless as a proof of the existence of God.

Each of the two forms of cosmological argument discussed here is more sophisticated than the simple cosmological argument presented above. Each of the two cosmological arguments discussed here draws a distinction between the type of entity that the universe is and the type of entity that God is, and in doing so gives a reason why the existence of the universe stands in a need of an explanation while the existence of God does not. Each therefore evades the objection outlined above.

In the case of the kalam cosmological argument, the distinction drawn between the universe and God is that the universe has a beginning in time. Everything that has a beginning in time, the kalam cosmological argument claims, has a cause of its existence. The uncaused existence of God, who does not have a beginning in time, is consistent with this claim, and so does not present the problem encountered in the discussion of the simple cosmological argument above.

In the case of the argument from contingency, the distinction drawn between the universe and God is that the existence of the universe is contingent, i.e. that the universe could have not existed. Everything that exists contingently, the argument from contingency claims, has a cause of its existence. The uncaused existence of God, whose existence is not contingent but rather is necessary, is consistent with this claim, and so does not present the problem encountered in the discussion of the simple cosmological argument above.

Each of these two forms of the cosmological argument, then, evades the objection introduced above in a distinct way. The two arguments are therefore distinct, and so warrant individual assessments.

The Kalam Cosmological Argument

The temporal, kalam cosmological argument, dates back to medieval Muslim philosophers such as al-Kindi and al-Ghazali. It has recently been restored to popularity by William Lane Craig.

Like all cosmological arguments, the kalam cosmological argument is an argument from the existence of the world or universe to the existence of God. The existence of the universe, such arguments claim, stands in need of explanation. The only adequate explanation, the arguments suggest, is that it was created by God.

What distinguishes the kalam cosmological argument from other forms of cosmological argument is that it rests on the idea that the universe has a beginning in time. Modal forms of the cosmological argument are consistent with the universe having an infinite past. With the kalam cosmological argument, however, it is precisely because the universe is thought to have a beginning in time that the existence of the universe is thought to stand in need of explanation.

The argument has the following structure:

(1) Everything that has a beginning of its existence has a cause of its existence.

(2) The universe has a beginning of its existence.

Therefore:

(3) The universe has a cause of its existence.

(4) If the universe has a cause of its existence then that cause is God.

Therefore:

(5) God exists.

The first premise of the argument is the claim that everything that begins to exist has a cause of its existence. In order to infer from this that the universe has a cause of its existence the proponent of the kalam cosmological argument must prove that the past is finite, that the universe began to exist at a certain point in time.

The crucial premise of the kalam cosmological argument, then, is the second: “The universe has a beginning of its existence”. How do we know that the universe has a beginning of its existence? Might not the universe stretch back in time into infinity, always having existed? The proponent of the kalam cosmological argument must show that this cannot be the case if his argument is to be successful.

Advocates of the kalam cosmological argument claim that it is impossible that the universe has an infinite past. The existence of an infinite past, they say, entails all manner of logical absurdities.

If there exists an infinite past, then if we were to assign a number to each past moment then every real number (i.e. every postive integer) would be assigned to some moment. There would therefore be no unassigned number to be assigned to the present moment as it passes into the past. However, by reassigning the numbers such that moment number one becomes moment number two, and moment number two becomes moment number three, and so on, we could free up moment number one to be assigned to the present. If the past is infinite, therefore, then there both is and is not a free number to be assigned to the present. That such a paradox results from the assumption that the past is infinites shows that it is not possible that that assumption is correct. The past, it seems, cannot be infinite, because it is not possible that there be an infinite number of past moments.

The Argument from Contingency

The modal cosmological argument or “argument from contingency” is the argument from the contingency of the world or universe to the existence of God. The argument from contingency is the most prominent form of cosmological argument historically. The classical statements of the cosmological argument in the works of Plato, of Aquinas and of Leibniz are all statements of the modal form of the argument.

What distinguishes the modal cosmological argument from the kalam cosmological argument is that it is consistent with the idea that the universe has an infinite past. The kalam cosmological argument rests on the controversial claim that the universe has a beginning in time. The argument from contingency, in contrast, is consistent with the universe having existed from eternity.

The argument from contingency draws on the distinction between things that exist necessarily and things that exist contingently.

Something is “necessary” if it could not possibly have failed to exist. The laws of mathematics are often thought to be necessary. It is plausible to say that mathematical truths such as two and two making four hold irrespective of the way that the world is. Even if the world were radically different, it seems, two and two would still make four. God, too, is often thought to be a necessary being, i.e. a being that logically could not have failed to exist.

Something is “contingent” if it is not necessary, i.e. if it could have failed to exist. Most things seem to exist contingently. All of the human artefacts around us might not have existed; for each one of them, whoever made it might have decided not to do so. Their existence, therefore, is contingent. You and I, too, might not have existed; our respective parents might never have met, or might have decided not to have children, or might have decided to have children at a different time. Our existence, therefore, is contingent. Even the world around us seems to be contingent; the universe might have developed in such a way that none of the observable stars and planets existed at all.

The argument from contingency rests on the claim that the universe, as a whole, is contingent. It is not only the case, the argument suggests, that each of the things around is us contingent; it is also the case that the whole, all of those things taken together, is contingent. It might have been the case that nothing existed at all. The state of affairs in which nothing existed at all is a logically possible state of affairs, even though it is not the actual state of affairs.

It is this that the argument from contingency takes to be significant. It is because it is thought that the universe exists contingently that its existence is thought to require explanation. If the universe might not have existed, then why does it exist? Proponents of the cosmological argument suggest that questions like this always have answers. The existence of things that are necessary does not require explanation; their non-existence is impossible. The existence of anything contingent, however, does require explanation. They might not have existed, and so there must be some reason that they do so.

Critics of the argument from contingency have sometimes questioned whether the universe is contingent, but it remains at least plausible to think that it is so.

The only adequate explanation of the existence of the contingent universe, the argument from contingency suggests, is that there exists a necessary being on which its existence it rests. For the existence of the contingent universe must rest on something, and if it rested on some contingent being then that contingent being too would require some explanation of its existence. The ultimate explanation of the existence of all things, therefore, must be the existence of some necessary being. This necessary being is readily identified by proponents of the cosmological argument as God.

The argument from contingency, then, can be summarised as follows:

(1) Everything that exists contingently has a reason for its existence.

(2) The universe exists contingently.

Therefore:

(3) The universe has a reason for its existence.

(4) If the universe has a reason for its existence then that reason is God.

Therefore:

(5) God exists.