Norm asks for a second opinion on the anthropic principle, in relation to our existence, the laws of physics and the ‘multiverse’. He seeks input from “someone who understands the science”. Well, that definitely isn’t me, but I think I do at least understand the logic (and I think Norm does too, really).
If life-supporting physics is extremely unlikely (and I make no claim about whether that’s so or whether it’s even knowable), then the fact that our universe has just that is, to say the least, curious. Possible explanations are: random chance; deliberate design; or a change of perspective that makes this unlikely situation less remarkable. (The other option is that the physical laws we actually have are in some way necessary – that is, to deny the antecedent.)
The first and second options are the sort of thing that scientists will only seriously settle on if they’ve exhausted all other possibilities, the first being no explanation at all and the second simply shifting the missing explanation back a stage and magnifying it in the process. The third route, which the multiverse hypothesis takes, say that if there is a vast multitude of physical universes, then there are bound to be some life-supporting ones. The fact that we’re in such a universe is no more surprising than the fact that fish are found in seas and not in deserts.
Of course, a multiverse would be quite a thing, and naturally the people from Occam’s Razors Ltd are hesitant to invest. But which is the more extravagant hypothesis: lots and lots and lots more physical stuff, or a creator?
(I don’t rule out other possibilities; I’m no more a scientist than Jennifer Aniston. And I’m also not saying that an atheistic desire to resist the design argument is motivating the idea: the Everett interpretation of quantum mechanics gets us into that sort of territory.)
The idea that Norm rightly identifies as unreasonable is that “our physical laws might be explained ‘anthropically,’ meaning that they are as they are because if they were otherwise, no one would be around to notice them”. This of course is rubbish (and backwards causation at that).
All the anthropic principle can give us is the weaker, epistemic conclusion that any observed physical laws must be such as to enable the existence of lifeforms that can observe them. But that’s nothing special: it’s like saying that all instances of drunks recovering their dropped car keys take place under lamp-posts (because when the keys get dropped somewhere dark, they remain unfound).