Sticking a fork in Natural Selection (Introduction)

by dhw, Friday, December 09, 2011, 12:25 (4734 days ago) @ David Turell

MATT: But you still dodge the question. There's plenty of good reasons that we lack transitions from pre-cambrian to cambrian. The snapshot view of the fossil record *underlines* this. What right do we have to expect that the fossil record will conform to our expectations?

DAVID: I'm not dodging anything. Give me some good reasons for the gap. And is a monster developmental gap from Edicarans and Bilatarians. And the Cambrian is not a one-shot wonder as Gould presented. It is now found all over the world in Cambrian shale.

MATT: The question I'm asking, is why don't you consider that the gaps in the record are explained by the fact we haven't found those fossils, for whatever reason. (ie, too soft, etc.) this is of course the first explanation I go to when the gap discussion appears.

DAVID: You are doing a 'Darwin'. He was troubled by the gaps and expected them to be closed. There are some very persistent gaps in time and form. What would you say if they never closed?

In view of the title of this thread, I’m having difficulty discerning the focus of this discussion, so since there's a slight lull, may I step in? Darwin was indeed troubled by the gaps in the fossil record, but these have absolutely nothing to do with natural selection, which simply determined which organs and organisms survived. What so many critics ignore is that the great kerfuffle over evolution did not concern NS but common descent – the church could not abide the idea that humans and apes had a common ancestor, and that God did not create all the species separately. That went against the conventional interpretation of Genesis. So what exactly is the controversy over the Cambrian Explosion? Anti-evolutionists may claim that the gaps in the fossil record indicate that God DID create species separately. However, David has always maintained that he believes evolution took place, which means that every creature came from another creature. In that case, we must accept one of two possibilities: either there were transitional forms of which we have no record, or there were leaps from one form to another – i.e. through sudden major innovations. The latter is contrary to Darwin’s theory of gradualism, which many of us feel has been superseded by Gould’s punctuated equilibrium, and which is also coming under fire with increasing evidence of rapid change in existing organisms.

No-one has yet explained why the Cambrian “leaps” should have taken place, but if they coincided with major changes in the environment, the implication might be that innovation as well as adaptation can be sparked off by such changes. This is why epigenetics may prove to be a key factor in the process, though it’s still too early to say.

Where does God fit in? Whatever the mechanism might be that enables organisms to adapt and to innovate, David thinks it’s too complex to have assembled itself by chance, and so he believes in design. The Cambrian Explosion is an extreme example of the rich creative potential of this mechanism. Whether there are or are not any transitional fossils will only reflect the speed and completeness of the changes – the greater the speed, the more efficient and creative the mechanism, and so the greater the odds against chance. But whether there is or isn’t a designer doesn’t alter the nature of the mechanism or of the process! David also believes in pre-planning, but this is just one variation on the design theme – others being that God started it all off and then sat back to see what would happen, or that God started it off and continued to experiment. If there is no God, chance started it all off and then it followed exactly the same course as if God had pre-planned it, sat back to watch, or carried on experimenting. And so the discussion is the same as usual – chance v. design. There are no forks being stuck into natural selection or even Darwinism in general, apart from the undermining of gradualism.