Some have objected to the Kalām by suggesting that the word “universe” is being used differently by physicists than how Dr. Craig has used it.
For example, Alexander Vilenkin has been referred to (supposedly via email) as support for this objection: “It is certainly more than what we can have access to. Regions beyond our cosmic horizon are included. But if there are other universes whose space and time are completely disconnected from ours, those are not included. So, by “universe” I mean the entire connected spacetime region.”
Here is Dr. Craig’s response:
“Whether there are other causally disconnected universes is entirely irrelevant to the soundness of the Kalām cosmological argument. Think about it: suppose, for the sake of argument, that there are other universes causally disconnected with ours. They are for that very reason irrelevant to the conclusion of the Kalām argument. In particular, they cannot be the cause of the universe spoken of in the argument’s conclusion. So all my arguments concerning the properties of the cause of the universe go through as before.”
“Thus, the non-theist cannot avoid God by the metaphysical conjecture that other disconnected universes might exist. Of course, if the non-theist conjectures that these other universes are causally connected to ours, then they are comprised by the universe and we are right back to Vilenkin’s arguments that there is no tenable model of the universe, so defined, which does not have a beginning in the finite past. The so-called “null topology,” discussed by Jim below, if construed as physically real, is by definition part of the universe and so in need of an explanation of its coming into being.” (Italics mine).
You can read more on this topic here at Reasonable Faith.
More on this on the next post.