Our email corespondent Laszlo makes this point about the multiverse hypothesis that seeks to do an end run around cosmic fine-tuning and the implication of design in the cosmos.
The point of proposing the multiverse theory is that there exist an infinite number of universes of which ours happens to be lucky enough to have “just right” conditions for life. Implicit in the proposal is the belief that the system which generates universes always cycles through all possibilities of fundamental constants (gravitational constant, speed of light, etc.) so that each universe is randomly different. But since no one has any idea how universes are generated in such a scenario, why should we think that the constants in each universe will be different? Why might they not be always the same due to some fundamental quality of these constants? Analogously when we combine hydrogen and oxygen, we do not expect the result to be an infinite array of compounds. We expect water because the fundamental laws of chemistry generate only that compound.
That is a very good question. More:
Briefly, what reason is there to believe that a universe generating system necessarily produces every conceivable variation of all the physical constants? Given that the proposal is metaphysical and not subject to observation, doesn’t it boil down to mere preference? After all if we’re going to describe Cerberus, the three headed dog who guards the gates of Hades, we can describe him any way we wish. Who can ever refute the claim that he is red with bulldog heads and floppy ears?
Image: Cerberus, Royal Institute of Technology, Stockholm/Wikipedia.