If the precise value of many physical constants had been different, the universe would not have supported life, human life, consciousness, philosophy and us.
Probably the most persuasive argument for the existence of God -- I don’t mean to philosophers and logicians, but to ordinary people -- goes something like this: All of this -- that is, a world with life, intelligence, beauty, humans, morality, etc., -- couldn’t have come about by accident. It must be due to some intelligent, powerful Being -- and that’s what God is.
The fine-tuning argument is a modern, up-to-date version of this argument. It takes off from something that serious physicists, religious or not, tend to agree on. Here’s how Freeman Dyson put it:
"There are many . . . lucky accidents in physics. Without such accidents, water could not exist as liquid, chains of carbon atoms could not form complex organic molecules, and hydrogen atoms could not form breakable bridges between molecules" (p. 251)--in short, life as we know it would be impossible.
All these things Freeman Dysan calls lucky accidents --- which include the initial distribution of matter when the Big Bang banged --- and values of some fundamental constants --- can be thought of the universe as being fine-tuned so as to allow for the emergence of life and all those other good things that come with it.
Then the argument is: Isn’t it more plausible to suppose that these things were not accidents, but happened according to a plan of some intelligent being? If I found an aquarium in your house, with water and plants and food in the just combination required to keep goldfish happy, I might reasonably infer that someone put it there because they wanted goldfish, not that it occurred by accident. Similarly (a bit) the universe has ended up with a little aquarium for humans, reason and morality, namely, our earth So isn’t it reasonable to suppose that, rather than being an accident, things were set up to allow for this development?
But such fine-tuning, in order to make life possible, requires a fine-tuner. This would have to be some Being with incredible knowledge and power. That seems to amount to God, or at least a God.
That’s basically the fine-tuning argument. We could elaborate the physics involved, and put the reasoning in the form of Bayes Theorem. But it wouldn’t change the basic idea. (Well, actually I couldn’t do this, but if you Google our guest, “Robin Collins”, you’ll find all the elaboration you want.)
I’ve seen this argument developed in the august pages of philosophy journals, and in thought pieces by eminent physicists. And I’ve heard it expressed --- very well in fact --- by a speaker at my Rotary Club. It may not be responsible, at least not yet, for a world-wide revival of religion. But it’s taken seriously by a lot of intelligent and thoughtful people.
Still, I have some problems with it.
The reasoning basically says: A life-supporting universe is intrinsically unlikely. A powerful and intelligent Creator who wanted such a universe would explain it. So the fact that we have a life-supporting universe makes it likely that there was a powerful and intelligent Creator.
So far, so good. In general, if an event happens, that makes the hypotheses that would explain it more likely. But how likely does it make them? It depends on how likely the hypothesis is independently of the event --- it’s “prior probability”--- and how likely the alternative hypotheses are.
One alternative is it was one lucky cosmic coincidence. If it hadn’t happened, we wouldn’t be here to be surprised, so maybe it shouldn’t be that surprising to us.
Another alternative is that there are a whole bunch of universes --- not just galaxies in our universe, but complete universes. Given a string of universes, one would expect the various combinations of parameters for basic physical factors to show up in endless combinations, just as one expects all of the individually unlikely combinations of hands to show up, if one plays bridge long enough. Are these hypotheses initially more or less plausible than the God hypothesis?
This depends on what would be required by the existence of such a Creator. Wouldn’t that in turn require the existence of a Creator-friendly universe, or proto-universe, with parameters set to allow for the development of such a powerful and wonderful Being, capable of setting the parameters for our universe? If so, it doesn’t seem we have gained much with the God hypothesis.
The argument will only be plausible to those who already see the existence of some such Being as not completely implausible, and not requiring a similar explanation of its existence.
I also have some doubts about what we are supposed to do with the conclusion of the argument, even if we agree with it. Philo, Hume’s spokesman in the Dialogues on Natural Religion, agrees by the end that the more likely hypothesis is that the world was created by some sort of intelligent being or beings. But he points out that this doesn’t in and of itself provide much evidence for the Christian God --- or the God of any other religion, he might have added. How do we know it was one God, and not a committee? How do we know it is benevolent, when the evidence on that issue is so mixed? It’s going to take quite an argument to get from fine-tuning to not coveting they neighbor’s wife and closing bars on Sundays and the other things some people think they know that God wants us to do.