Originally posted by UmbrageOfSnow
His point, or one of them anyway, is that the name 'Jessica' is not chosen simply by picking a random number of random letters out of the alphabet. No names are. The point is that you can't calculate probabilities of events correctly when you make bad assumptions about how they would occur.
Yes, this was essentially my point. There are a lot of other little things too, but they all basically fall under the same point about bad assumptions.
The essay relies critically upon certain assumptions.
1) Abiogenesis had to begin with proteins as complex as the one described in the essay. If much simpler proteins were possible, then the probability of forming a 100 amino acid protein, no matter what else the assumptions, is irrelevant to the likelihood of abiogenesis.
2) Amino acid molecules link up in an independent manner. Assuming independence, lets the authors multiply probabilities together and really jack up the exponents, which quickly yields incredibly tiny numbers. However some amino acids may have been more likely to bind to some existing combinations more than to others for all sorts of reasons (by physical properties of amino acids, environmental bias, or simply a higher frequency of one amino acid than another.).
This concept is not particular to amino acid molecules, but to all sorts of things and is called "conditional" probabilities. For instance, if we randomly pick some one from the world, it is fairly unlikely that that person's name is Jose. On the otherhand, if I tell you that the person is Mexican the "conditional" probability that that person's name is Jose is a lot higher. If I tell you that the person is male, it's even higher still. The way the essay treats the problem of protein building, the current set of say 34 amino acids has absolutley no effect on the probabilities for what the 35th amino acid will be.
3) They calculate the probability as if some one had to draw amino-acid molecules one by one and could only succeed if they got exactly the same 100 amino acid molecules that make up their particular protein. Perhaps smaller subchains existed fairly well. Later these chains connected along with other amino acids.
4) Another problem, which has already been pointed out, is that it assumes that the number of trials is very small (perhaps one). As if life could have only arisen if this wacky amino acid experiment happened on the first try. The environment described by some one here (scotty?) is one in which an extremely large number of potential combinations are being "sampled" all the time for many years.
If you toss a coin 20 times, the ex ante probability that you will get 20 heads is 1 in 1,048,576. Pretty much not gonna happen for you. However, if you have every person in China toss a coin 20 times, it is extremely likely that some one will succeed in throwing 20 heads.
The above points are valid criticisms that one can bring up with almost no knowledge of abiogenesis theory or biology or chemistry. The key is that probability theory applies in all sorts of situations, whether it's meeting people in a room, insuring drivers, or forming living matter from non-living matter. When you can peel back the math to lay bare the assumptions, you don't get bogged down by deliberate obfuscation.
As for what the best way to model abiogenesis is, I'll leave that to people who know a lot more about biology and chemistry than I do. They'll have a better idea about the environment and natural laws governing the relationship between amino acids. They'd know what distributions best describe the populations of amino acids (rather than a uniform distribution, which is what the essay basically assumes). Anyway, I hope you didn't take all this as a challenge to you. I wasn't intending to call you out. But I think it is important that one be very suspicious when Creationists start throwing around numbers.
22 Jul '06 20:34
Neanderthal DNA
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