This is the the twenty-second post in my Theories of Knowledge and Reality series. Follow the link for more on the series and for links to other entries as they appear. In the last post, I looked at the fine-tuning design argument for the existence of God, along with an initial look at the many-worlds conjecture as a response to the argument. This post will spend some more time comparing that conjecture with the designer explanation for the fine-tuning of constants in physics.
Is this objection decisive? It's an alternative explanation, and we need just one alternative explanation to show that the argument original designer explanation isn't the only one. So we have two explanations to consider. Which should we prefer? Which is more reasonable, theism or all these myriads of cosmoi? Both explanations do seem to explain the surprising fact about the constants of physics, and they seem to account for this fact equally well, but how do you weigh the simplicity of each theory? It's not as if both agree on the core that everyone agrees on, and then one goes beyond that to postulate all this excess baggage. Both scenarios contain something that in their theory about ultimate reality beyond what a naturalist might want to say.
Theism, even the minimal sort necessary if you accept this argument, involves a designer or creator, which certainly goes beyond naturalism. Simplicity might nudge us to discount theism in favor of the many-worlds conjecture, since those worlds all seem to be additional parts of nature -- the kind of thing a naturalist already believes in. There are just lots more of them than the one we originally believed in. However, the many-worlds conjecture may require going beyond naturalism as well. Why do all the possible cosmoi (i.e. all the possible sets of constants) get generated? Is there some mechanism that generates these different universes, maybe all at once in different universes or maybe one after the other? What would this mechanism be? It's certainly not something you can just read off physics. There's no explanation offered why there would be such a mechanism. So it's not clear if this response really fits the naturalistic picture either. The many universes would be more of what we already believe in (though many, many more things), but the mechanism to get many universes is beyond the core theory. Yet theism involves a wholly different kind of thing, a designer, though just one thing and not very, very many. A theory can be simpler in terms of how many things it requires, and a theory could be simpler in terms of what kinds of things it requires. We have two theories. Each one is more complex than the other but in a different way.