Craig lists three live possibilities for the fine-tuning of the constants, forces, and parameters of the universe: He argues that this cosmic fine-tuning is due either physical necessity, chance, or design.
Feder and Zimmer write:
The first possible explanation for fine-tuning is physical necessity. This means that either the constants are necessary, brute facts of reality or that they deterministically derive from a deeper necessary law of physics.In other words, there doesn't appear to be any reason why the constants have to have the values they do. Nothing necessitates those values. The second possibility in Craig's schema is chance about which they say this:
As physical necessity is not a very good theory to begin with (it doesn’t seem plausible that physicists will be able to derive the precise values from a deeper theory) and, more importantly, it doesn’t explain why the constants are fine-tuned (this just remains an immense coincidence), it’s reasonable to discard physical necessity as an explanation of fine-tuning.
The second possible explanation for fine-tuning is chance. If there is only one universe, physicists calculate that it would be incredibly unlikely that the values of the constants would be in the small range that would allow our complex universe to exist. Chance only becomes plausible if there are a tremendous number of alternate universes with different values of the constants — a multiverse.They point out that the multiverse hypothesis is beset by numerous difficulties among which is that it's "an untestable speculative theory of an infinite number of observable universes [which] is a clear deviation from the tried-and-true scientific method." Moreover, it's an extraordinarily unparsimonious idea. Why postulate an infinity of unobservable worlds to explain why our world has just the properties it does when postulating a single intelligent agent would suffice?
The elimination of physical necessity and chance leaves intelligent agency as the best explanation for the fine-tuning of the universe since it's our uniform experience that wherever we find fine-tuning it's always the product of a mind. The only reason to exclude mind as the source of the fine-tuning we see in the universe is an apriori prejudice against any non-physical explanation, but apriori prejudices should be excluded by all open-minded thinkers.
They conclude the piece with a few seemingly minor criticisms of Craig's argument which you're invited to check out for yourself.
Tomorrow we'll look at the argument for fine-tuning based on probability. Meanwhile, if you didn't watch the video on Craig's elimination argument at yesterday's post I invite you to watch it. It's only five minutes long.
