I may be hopelessly naive in the matter of probability, though it is the one area of math that I have actually studied, but I am simply not terribly impressed with probability arguments. That’s probably (!) a major reason why I’m not impressed with intelligent design (ID). I’m particularly not impressed with probabilities calculated for processes that are not yet understood. If you don’t know all the factors, how can you calculate a probability?
On the other hand, it appears that many creationists are much more impressed with probabilities that are largely guessed, while they are not terribly impressed with extrapolation in historical studies. For them, it often doesn’t matter how much detail you get for the development of various structures in the past, it’s not enough, because it would only be testable if we could see every stage and explain everything.
Thus when an ID writer claims something is highly improbable, even though he hasn’t a clue how it actually happened, it impresses his fellow creationists, while when a scientist extrapolates development between existing specimens, the same creationists are totally unimpressed. Yet which of these is operating on the greater level of evidence?
If anyone is wondering why I see strong evidence for evolution, here’s the answer. I’m used to and respect historical methods. If you find a pottery type developing, and then you find several examples of stages, sequentially arranged by date, you can extrapolate a path from one style to the next. You don’t need an example of every pot. If you see writing develop from one style to the next, you don’t need every stage. You can extrapolate.
For me, the simple fact of large numbers of sequences in the development of complex structures suggests that such things have developed naturally. Extrapolating the intermediate steps is not terribly difficult for those who study these things, and it is a quite proper procedure. Challenging the observed sequence by indicating that it is improbable strikes me as absurd. The only proper challenge would be to say, “Here! This is where the intelligent designer intervened.” But of course, ID advocates do no such thing.
NCSE has produced a video, which I will embed below, that shows such a sequence on the development of the eye. It’s very clear, but it lacks some steps. I don’t know whether the video produced all the steps we know of, or just a sampling, but if these were the sum total of examples we have in a sequence of eye development, we would have good cause to believe that the eye evolved.