Craig's Kalam Cosmological Argument

William Lane Craig offers the following argument for the claim that the universe has a cause.

Craig's defense for premise 1 is fairly brief and straightforward. He appeals to a very powerful metaphysical intuition - the intuition that things can't just "pop into existence out of nothing." The obvious consequence, he thinks, is that everything that begins to exist must have a cause. Craig devotes most of his energy to showing that premise 2 is true. He offers two main philosophical arguments, and two "scientific confirmations" of this result. Both philosophical arguments are attempts to prove that there cannot have been an infinite series of events prior to the present moment. From this it follows that there must have been a "first event" in the succession of events that make up the history of our universe. And this, of course, means that once upon a time, our universe began to exist.

Finally, Craig offers a brief argument in favor of the conclusion that the cause of the universe must be a person.

Below I concentrate on the two philosophical arguments for premise 2, and on Craig's argument for thinking that the universe is a person.

First philosophical argument against an infinite temporal regress of events.

Craig first distinguishes between a "potential" and an "actual" infinite. He claims that an infinite temporal regress would be an actual infinite, and that it is impossible for there to be an actual infinite.

Potential vs. Actual Infinite

An actual infinite is impossible. Second philosophical argument against an infinite temporal regress of events.

But even if the idea of an actual infinite were not absurd in general, Craig thinks that the idea of an actually infinite series of past events would still be absurd. His argument goes like this:

Here's an example designed to show what it means to say that a series is formed by "successive addition." The twentieth century will soon have been completed. First the year 1900 passed by, and then the year 1901, and so on up until the present year, 1996, which is also passing by. Soon 1999 will have passed by as well, and then the series will have been completed.

Now Craig thinks that if the past consisted in an infinite series of events, then the series of events that terminates in the present would have been formed by successive addition in this same sense. One event after another would have been "added" to the sum of those that have already passed by, up until the present event.

But Craig thinks this is absurd. Since the series stretches infinitely into the past, it seems that we have arrived at the "end" of an actually infinite series of events, each of which was successively added to the previous ones.

There is yet another way in which Craig thinks we can see the absurdity of an infinite series of past events. Imagine that someone - call him Jones - has just finished counting the number of days that have passed by. The number, he announces, is infinite. But Jones would have had to give the same answer yesterday, and the day before that, and the day before that. So it seems that Jones would have finished counting down from infinity long before today - and indeed, before any given day. So there is no day on which which he could be counting because he would already have finished counting prior to that day.

How, exactly, is this supposed to show that the series of past events could not have been formed by successive addition? Perhaps Craig means to be arguing along the following lines:

Why a person?

What can we say about the nature of the first cause of the universe? The first thing to see is that, prior to creating the universe, the cause of the universe must be an eternal being. It cannot have begun to exist. Otherwise it would be just as much in need of a cause as the universe. So Craig thinks it is best to assume that the cause of the universe enters time only when it creates the universe. The first moment of time then coincides with the beginning of the universe.

But is there a divine person who decides to create the universe? Or is the cause of the universe only a "mechanical", non-personal, cause that is sufficient to produce it? Craig thinks it can't be the latter, since if it were, the universe would have to be just as eternal as its cause, contrary to what we have proved. Let me explain.

By a "mechanical" cause, Craig means a cause that automatically produces its result as soon as it comes into existence. For example, if water falls below a certain temperature, it automatically freezes. If the universe had this sort of cause, it would have to be just as eternal as its cause. Like its cause, it could not have begun to exist.

The only other possibility, Craig thinks, is that the universe was created by a person who freely chose to exercise its power to create. That way, we don't get the unwanted implication that the universe is beginningless, since a person does not automatically exercise its creative power.

A problem with Craig's defense of premise 1

There is one important difficulty that I want to mention briefly. If there is no time prior to the beginning of the universe, then Craig's main argument for saying that the universe must have a cause is considerably weakened. Recall that he thinks it would be absurd to suppose that the universe just popped into existence out of nothing. That's why he thinks that if the universe has a beginning, it must have a cause. But whether or not the universe has a cause, the universe doesn't pop into existence out of nothing. If there is no time prior to the beginning of the universe, then even if the universe has no cause, it is still not the case that once upon a time there was nothing, and then - pop! - the universe sprang into existence.