Saturday, December 18, 2010

Argument by Probabilities

Okay, you guys all know the gist of how this argument goes:

Imagine you have ten pennies, and you toss them all up in the air. What're the odds that they'll all land on heads?

(Of course, as we all know, the odds are 1/(210), or 1/1024)

Now, look at the complexity of DNA, or of cells, or of the human eye. Look at how Earth happens to be in the Goldilocks zone, how the universe expanded at just the right speed to allow matter to coalesce into stars and planets. How can you possibly not believe in God, when your very existence is much, much more improbable than those pennies all landing on heads? You'd have to be stupid to think we exist by accident!

First, this argument shows a fundamental misunderstanding of evolution and of the age and size of the universe, but I'll ignore all that and just cover the probabilities bit.

I've never been much of a fan of probabilities because, as a hard determinist, I think they're something of a pseudoscience. When you flip ten pennies, the odds are 100% that you'll get whatever you got, and 0% that you'll get what you didn't get. There are so many factors that determine how those pennies will land — how they're arranged in your hand before you throw them, how you actually throw them, etc. — which are all essentially caused by something preceding it, ad infinitum to the Big Bang.

Plus, let's consider the "all landing on heads" part. It's just like, I dunno, drawing five cards off a deck and getting a royal flush in spades in order — we place undue significance on that specific pattern, because it has some subjective value to human beings, whether because of the uniformity and order or because it means you're guaranteed to win the pot and you can milk the suckers around the table for all they're worth. But really, even if we accept probabilities for a second, it's still a stupid argument.

If we label all the pennies — penny 1, penny 2, penny 3, etc. — and then take the probabilities, we notice that the odds of the pennies landing in any combination is just as improbable as the next. You can grab those ten pennies, toss them in the air, and you're getting a miracle no matter how they land.

Same with being dealt five cards off the top of a deck, too. Taking into account the suit of each card, every hand you're dealt comes with a mind-boggling improbability of 1 in 311,875,200.

And yes, if you draw five cards off the top thinking "my goal is to get a royal flush," you shouldn't get your hopes up. But who's to say human beings are the goal of the universe? We're just an assembly of five cards that sit around claiming that the five cards we are specifically are of cosmic significance. We are every bit as miraculous as the Great Red Spot or the rings of Saturn, but neither Jupiter's giant storm nor Saturn's rings have the audacity to claim they're the point of the universe.

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