Videos: A thousand pennies

A thousand pennies

3 January 2009

ZJ: There is an argument that is often used against evolution and abiogenesis, and in favor of some sort of intelligent designer, often characterized as God. The argument is typically constructed as follows: Life on earth is so diverse and complex, it is very improbable that it arose by random chance. Therefore, life must have been designed by an intelligent entity. And I really want to make sure I got that right, because this argument contains so many flaws, it almost feels as though I'm setting up a straw man. But apparently people actually do find it convincing, which really testifies to the tragic degradation of critical thinking skills in modern society.

In a less formal context, this argument is often seen as a personal expression of incredulity: "I just can't believe that everything is here by accident." And that's actually quite revealing, because personal incredulity is the backbone of this argument, even in its more well-articulated forms. And this is fallacious. It is not a valid argument to say, "I just can't believe it, and therefore it must not be true." If you use this argument, you're not even discussing the phenomenon in question. You're just making a statement about yourself and how you feel about it, which has no bearing whatsoever on the phenomenon itself. It's just not an argument.

And this is a ridiculous and poorly-informed objection anyway, because the diversity of life did not arise by random chance, or by accident, or however they choose to characterize evolution. A degree of randomness is present in the genetic code of organisms. This randomness is introduced by mutations and by genetic recombination and reproduction. And an organism's genetic code heavily influences its phenotype, that is, the various traits it will express. An organism's traits will affect whether or not it is capable of surviving in its environment, and reproducing to pass on its traits.

So the question of its survival is not random. If it can survive in its environment, it will. If not, it will die. That is not random, that is called natural selection. That's what natural selection means: selection. An organism's survival is not determined by a coin toss; it is not the result of random chance. If it were, evolution wouldn't work. Richard Dawkins phrased this as "the nonrandom survival of randomly varying replicators", which sums it up quite succinctly.

There's another flaw in the original argument: Even if we uncritically accept that life evolved by chance alone and that this is massively improbable, why would this lead to the conclusion that an intelligent entity designed all these lifeforms? If this is about probability, does that mean it's more probable that an intelligent being created all the life on earth? What is the probability of that? How likely is it that an entity so powerful and intelligent even exists, let alone actually designed every lifeform on the planet? How is it that this being left no evidence of its handiwork, or even its own existence, and instead left a trail of false evidence that consistently misleads us to the conclusion that life evolved?

And wouldn't this designer be as complex as, or even more complex than the diversity of life it designed? So where did this designer originate from? Did it come into existence by chance? What's the probability on that one? Has anyone crunched the numbers on this? Has anyone actually compared the probability of a designer to the probability that life evolved without having to be designed? Because if nobody has accurately figured this out, then there is no basis to claim that a designer is somehow more likely than the evolution of life.

Yet even if we did accept that evolution is incredibly improbable, and even if it was far more probable that life was designed by an intelligent being, this argument still would not accomplish its goals. It would not prove that evolution didn't happen, and it would not prove an intelligent designer exists. Why? Because massive improbability does not stop something from actually happening. Things can be unbelievably improbable, and yet, they still happen, against all odds. And this can be demonstrated quite easily. You can experiment with impossible odds at home, with common items.

First, go get a thousand pennies. If you don't have a thousand pennies, well, they only cost $10. Now, go get a thousand little stickers, and put a sticker on each penny. Then, write a number on each penny, numbering them from 1 to 1,000. Once you're done with that, you go and grab your thousand pennies, numbered 1 to 1,000, and find a nice big, open, flat area. Take all those pennies, and throw them in the air, and let them fall on the ground. Now, start looking through those pennies, and for every numbered penny, write down whether it landed as heads or tails. Go through all of them, until you've recorded whether every one of those thousand pennies landed on heads or tails.

Now, how likely is it that all of those pennies would have landed in that specific pattern of heads or tails? Well, this actually is something we can crunch the numbers on. If you flip 1 penny, there are 2 possible ways it could land: heads or tails. If you flip 2 pennies, then there are 4 possible ways they could land, because both of them can land as either heads of tails. 2 possibilities times 2 possibilities is 4. And if you add a third penny, then again you're multiplying that by the 2 possibilities of the new penny, and you've got 8 possibilities in total. And if you keep going up to 1,000, that's 2 times 2 times 2 times 2 and so on, 1,000 times. It's 2 to the power of 1,000 (2¹⁰⁰⁰).

So, what does that come out to? Well, it's a big number. A really big number. It's about 10 to the power of 301 (10³⁰¹), that is, 1 followed by 301 zeroes. That is a huge number. And that is the number of possible ways a thousand pennies could land. So, the probability that your pennies would land in the specific configuration that they did, is 1 in 1 followed by 301 zeroes (1/10³⁰¹).

Do you have any idea how unlikely that is? Those are astronomical odds. In fact, they're beyond astronomical. If you flipped a trillion sets of a thousand pennies a trillion times every nanosecond from since the universe began, it's still very unlikely that you would have gotten two identical results by now. Every star in the universe would burn out and the universe itself would freeze before identical results started showing up. That's how long it would take. It takes that long because there's such an enormous number of possibilities.

You and your thousand pennies faced impossible odds. The odds were overwhelming that they would land in any pattern other than the way they actually landed. And yet they landed in that pattern. They beat the odds. If you think improbability can stop something from actually happening, those pennies shouldn't have even fallen on the ground. But they did.

And that's the real flaw of the improbability argument. You can't look at something that's already happened, and say, "Oh, well that's really unlikely, so that means it didn't happen", when there's overwhelming evidence that it did happen. That evidence must be acknowledged, because big numbers won't make it go away.

So the next time you hear someone say, "Well, I just can't believe everything got here by accident", throw a thousand pennies at 'em.

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