It is common to argue that because everything we experience appears to have a cause for its existence, then the totality of everything (the universe) must also have a cause for its existence. It is assumed that the universe cannot be self-caused, so therefore the cause must be outside the universe — God, in other words. Is this a legitimate argument? Can we conclude that the universe has a cause because everything in the universe has a cause and, therefore, that some particular god exists?
The most obvious reason why this is not a legitimate argument is the fact that it commits a very basic logical fallacy: the Fallacy of Composition. This logical fallacy occurs whenever someone takes something that is true of certain objects and assumes that it must be true of some whole or class that the parts are members of. Claiming that the universe must have a cause if everything in the universe has a cause is akin to claiming that a penny must be invisible to the naked eye because each atom in the penny is invisible to the naked eye.
There is another serious problem with this argument, one which is more subtle but nevertheless significant because it deals with the very nature of the concepts we are using. Specifically, the nature of causation itself: the way we use and understand the concept actually precludes us from using it about the universe as a whole or to claim that universe was "caused" by some deity.
Time and Causation
In Arguing for Atheism: An Introduction to the Philosophy of Religion, Robin Le Poidevin writes:
[T]he causes which we have experience of take place in time and space, and this is not an accidental connection. We suppose things to have causes because we want to explain why those things came into existence at the times and places they did. We therefore look for the causes of those things in the conditions which obtained just before, and in the vicinity of, the thing in question.
Conditions which obtained elsewhere or at other times cannot provide the relevant explanation. Causation, then, is a temporal concept. (It is perhaps also a spatial concept, but I do not want to insist on that here.) It is this aspect of causation which threatens the inference from what we experience to a conclusion about everything which begins to exist.
To say that causation is a temporal concept means that causation occurs in the context of time — that causes and effects take place within time. Typically this means causes occur "before" effects, but even if the reverse could happen, cause and effect are still occurring within a temporal context. There is thus always some "time before" the cause and effect as well as a "time after" the cause and effect.
The idea of a-temporal causation is, as far as we can tell, incoherent. To see for yourself just how true this is, try to describe some cause and effect relationship without any implicit or explicit connection to time. You won't be able to do it — every description of a cause and an effect must take the temporal context and relationship into account, otherwise the very notion of "cause" ceases to make any sense.
Time and the Universe
Of course, "time" is an aspect of our universe and this means that we can't speak of "causation" outside the context of our universe. When we accept that a temporal context is necessary to talk about causation, we necessarily accept that our universe is a necessary context for us to talk about causation. If an a-temporal cause is incoherent, then a cause "outside" our universe is also incoherent.
This means that a "cause" of our universe is an incoherent concept. To rescue the argument, one has to develop a new conception of "causation" which is not dependent upon time. Perhaps this is possible, but it's not immediately obvious that it is or, even if successful, that it's a concept which refers to anything which actually exists.
More important right now is the fact that apologists trying to argue that our universe must have been "caused" have not created such a new concept, nor have they tried. Indeed, it's not clear that they even recognize that they have a problem in the first place, much less have any idea where to go for a solution. Perhaps if they did then their attempts might be taken more seriously; as it is, they really just have no idea what they are talking about.
Cause vs. Cause
Even if we suppose that apologists start to recognize this problem and actually construct a new, valid, and usable concept of "causation" that isn't dependent on time or any other aspect of our universe, this creates a new problem as well: apologists will no longer be able to analogize between causation within the universe to causation of the universe.
Remember the original argument is that we can conclude that the universe was caused because of the causation we witness now, but if we're using two radically different concepts that happen to get the label "cause" this inference is no longer logically valid. The fact that events in our universe require causes cannot logically entail that the universe requires a "cause" in this new, hypothetical sense. Making such an argument would mean committing an entirely new fallacy: the Fallacy of Equivocation.
This places all arguments about how the universe needs a cause on very uncertain footing at best. It would probably be best for apologists to abandon this line of reasoning in favor of something that might have some small chance of logical coherence.
