Q & A with Dr. Craig: Fine Tuning and Different Laws of Nature

by Reasonable Faith

Q: Hi Dr. Craig, I have been watching your excursus on natural theology and am up to the part about teleology. You mention an objection to the argument, that we could have other natural laws and it could be more probable than not, with other sets of laws, that life permitting universes do exist just by chance. You say we just don’t know the answer here.

Then you exclude the possibility of assessing possible worlds with other natural laws. You use the illustration of hitting a fly on a portion of blank wall, being much more improbable than probable, even if the area outside of the blank wall happens to be covered in flies. Of course in hitting flies on a wall we get to decide the portions. We get to say ‘we are looking at the probability of hitting the fly with in this area’.

But I’m confused about why we would be ‘allowed’ to do that when discussing the potential universes. What justification do we have to exclude worlds with other natural laws from our calculations of the probabilities?

(If the answer is, well, these are the natural laws we have so that’s all we must look at, then I don’t understand the goal of the project really. We could say the same thing about all the constants and quantities; since there is only one set that actually exists, that’s all we must address and then end up with a properly 0% chance of any other arrangement.



A: Thanks for the chance to clarify the point for you, Amanda! Let’s first be clear about the nature of fine-tuning. The fine-tuning concerns the values of the fundamental constants and quantities of nature. For purposes of the argument, one holds the laws of nature unchanged but alters the values of the constants and quantities. It’s very important that the laws be held unchanged, or we wouldn’t know what would happen if, say, the force of gravity were increased or decreased. Because the laws are held unchanged, physicists can predict what would happen…


Q & A with Dr. Craig: Fine Tuning and Different Laws of Nature | Reasonable Faith