Would Different Kinds of Life be Possible with Different Fundamental Constants & Quantities?

DR. CRAIG: You might be thinking at this point, but if the constants and quantities had had different values, then maybe different forms of life might have evolved. But that underestimates the really disastrous consequences of a change in the values of these constants and quantities. When scientists talk about a universe as being life-permitting, they're not talking about just present forms of life. By "life," scientists mean the property of organisms to take in food, extract energy from it, grow, adapt to their environment, and reproduce. It's the property of an organism to take in food, extract energy from it, grow, adapt to their environment, and reproduce. Anything that fulfills those conditions counts as life. And the point is, for "life" so defined to be possible, whatever form it might take, the constants and quantities of the universe have to be unbelievably fine-tuned. Otherwise disaster results. In the absence of fine-tuning, not even matter, not even chemistry, would exist, much less stars and planets where life might evolve. Any comment or question on that aspect of the fine-tuning argument?

QUESTIONER: Just a question about those astronomical numbers. What kind of parameters does somebody use to even calculate those kind of numbers, and is there any rational basis for it?

DR. CRAIG: Oh yeah, there's definitely a rational basis for it. What they do is they simply increase the value, say, of gravity, a little bit, and what you would discover then when you run the laws of physics with a slightly stronger gravitational constant is that everything will collapse in on itself and the universe will collapse into a black hole. On the other hand, if you just marginally weaken the force of gravity a little bit, then the laws predict that the universe would just expand so rapidly that stars and planets would never congeal, and so there would never be any sites on which life could exist. So because we're talking about universes governed by the same laws, physicists can alter these values and then run the laws and predict what sort of consequences would ensue. And what they find is, as I say, that if you alter these values by even a hairsbreadth stronger or weaker, then the universe turns out to be life-prohibiting rather than life-permitting in some way or other.