I would love your opinions on a science argument.

I’d like to debunk a common canard that these guys pull out because it came up recently in my own life - and I was looking for a way to explain probabilities well, that really anyone could see. I think I came up with a good way to say it.

Some of the more sophisticated ID types will misuse probability arguments when looking at sequences of amino acids in proteins or sequences of RNA/DNA which is really the same thing since the genetic material codes for the amino acids.

Their flawed argument goes something like if I have something like 20 possible amino acids to fill a place in the chain, and a protein that was say 30 amino acids long, then getting that specific protein completely at random would be at odds of 1 in 20^30, or one in twenty to the thirtieth power.

It is true that given those circumstances there are 20^30 possible proteins that could be made. It is true that the one you are looking at is one of them. However, that does *not* mean that the odds of getting it were 1:20^30.

This is of course completely wrong, because it ignores conditional probabilities and selective processes. In math speak, it grossly overestimates the possible outcomes in the probability space. Now how to illustrate that?

Let’s give the example of a happily married couple. Call them Sarah and Abe.

What are the odds that they got married?

You could start by saying well, there are six billion souls on the planet. Three billion are males. The odds of Sarah marrying Abe are one in three billion. This is exactly saying that there are three billion possible guys, and Sarah got one of them. It is exactly analogous to saying I picked one possible protein out of all the possibilities. Of course, that also assumes that all three billion guys have the same chance to marry Sarah, which is just wrong. It neglects her choices (which are of course, a form of selection).

Sarah is not going to marry a boy who is under or over a certain age. She is not going to marry someone who is already married. Right there, we have reduced the pool from three billion to at most 250 million. Abe’s odds just got a lot better… But they get better than that - much better. Out of those men Sarah is not going to marry someone whom she is not attracted to. If he has the wrong religion or politics or whatever for her, he’s out of the picture. If say Sarah is religious and Jewish, she is only going to look at religious Jewish men as possible husbands. The pool is now at most 100,000 single men of the right age - on the whole planet.

Again the analogy is that for certain proteins to arise, there must have been mutations in the codes that make them, however, if those mutations kill, then the proteins are out of the picture and so are any other proteins that would have depended on that first lethal mutation coming first.

But Abe’s odds are even better than that. Sarah is not going to meet every possible Jewish man. She lives somewhere and only knows so many people and at the end of the day, is simply not going to meet everyone before she chooses someone.

In fact, the pool is probably only about 100 guys that she will meet (and even give the time of day to) before she chooses. Of those hundred, most get culled for other reasons. When you get down to it, ask any married woman, there was her husband, and one or two also rans, out of all her boy friends and different dating partners, who ever really had a shot of marrying her.

Abe’s odds, rather than being one in three billion were really much better than that.