Wednesday, October 5, 2011

On the Fine-Tuning Argument

Of all the arguments for the existence of God, none bothers me as much as the fine-tuning argument. In summary, the argument posits that the universe is governed by very specific set of laws in which a slight aberration would render life impossible. Because it is highly improbable that these laws occurred by chance, we are urged to believe that a purpose-driven Being was responsible. An example of this sort of argument is the "watchmaker argument" propounded by Paley.

Before I point out specifically what is wrong with this argument, let me say that I believe all reason-based attempts to "prove" the existence of any God are doomed. Religion is ultimately based on faith, and it is a bit embarrassing to see it wrestle in the arena of scientific induction.

So let us begin. Consider a deck of cards. Without looking, I draw from it five cards: Ace of Spades, Three of Clubs, Four of Hearts, Seven of Hearts, and Queen of Clubs. It is a mongrel of a hand and utterly useless. No one would find it remarkable that I draw this particular hand.

Suppose instead I draw a straight: five consecutive cards irrespective of suit. This is a valuable hand, and observers would likely commend me on my good luck.

Suppose that I draw a royal flush: Jack through Ace of one suit. This is almost certainly a winning hand, and some people might be awed that I managed to come upon it. If I were playing in a game, some of my opponents might even suspect foul play.

What are the odds that I drew each of those hands? Statistics tell us that the odds of drawing a no-pair hand are 1 in 2, of a straight 1 in 254.8, and of a royal flush 1 in 649,740. Thus, at a glance, it seems reasonable that we attribute the highest value to the royal flush: it is the rarest of these hands.

But there's a mistake here. It is true that we have a 50% chance of drawing a hand that is within the class of no-pair hands; however, it is not true that this is the probability of drawing that particular hand. In fact, there are 1,302,540 ways of drawing a no-pair hand.

Why do we not find anything remarkable about me drawing that particular hand? The answer has to do with value assignments. Within a deck of cards, we have noticed certain combinations which are easy to remember and some of which are difficult to acquire. From this pool of memorable hands, we ranked them from least to most likely in terms of value.

In a sense, the combinations we choose are arbitrary. Take a hand consisting of all odds, for instance. It is not an easy hand to acquire, and it is certainly fairly simple to remember. It is not included among the "value-added" hands because whoever created these value assignments, for one capricious reason or another, simply decided against it.

Now consider a thousand decks, each consisting of a trillion cards. Each deck corresponds to a particular constant of the universe, and whatever card I draw from a given deck sets the value for the relevant constant. I painstakingly assemble my hand of a thousand cards, and lo and behold, I have by chance selected the exact combination that makes life possible. Everyone is amazed. My opponent, whose hand yielded a universe of nothing but rocks, flips over the table and accuses me of cheating.

Where there is cheating, there must be a cheater. Proponents of the fine-tuning argument believe that God is this cheater, and that he peeked into the decks to get exactly the right cards for his purpose.

But suppose that the universe of rocks demanded just as precise of a combination. If my opponent had replaced a few cards, he might have gotten some plants thrown into the mix; alternatively, he could have wound up with nothing more than star-dust.

"Well, look here," I would say to him. "Your hand is exceedingly improbable. You must have cheated to get your universe of rocks."

"That's stupid," he would say. "Who wants rocks?"

We, as life-forms, assign a high value to a combination that yields life. We are not interested in an equally likely combination that does not. However, in the void that was before the Big Bang, there was no value assignment to the infinite ways the universe could be. Marveling at the miracle of life is an activity justified entirely post hoc and is not a genuine assessment of how unlikely this particular universe is.

At this point, one might raise an objection. "That's all true," he might say. "But there's only one way the universe could have sustained life, and a near-infinite number of ways that it couldn't have. It's better than winning the lottery. Surely that counts for something!"

To this, I agree: if life is what you're looking for. If, for some reason, you wanted instead a universe full of rocks, you would be sorely disappointed with the way our universe turned out. If this metaphorical card exercise were actually a cosmic game in which rocks were the most highly-valued, then it is clear that our universe was dealt a mediocre hand.

Furthermore, there is scientific speculation that the much-revered constants of life are not as stringent as they once seemed. Certain laws of the universe may have been otherwise and still yielded life-forms similar to the ones in our universe. And of course, one cannot dismiss the possibility that our conception of life-form is too narrow, and that none-carbon-based life could have existed in a different universe.