Icons of ID: Darwinian predictions and the Cambrian

The first graph contrasts a logistic curve with an apparent step function. Problem is, there's not enough info about the units on the x-axis. The logistic curve can be made to appear like a step function by compressing the x-axis. And anyway, is there any reason that according to 'Darwinism' the number of phyla have to follow a logistic curve? It's nice that these guys enjoy playing scientist, but it's too bad they fool people.

If one drew a species tree of life diagram, (time vs. morphological distance) then all the taxalogical levels would be somewhat curvey horizontal lines. They are not straight horizontal lines. Once drawn, only the species line is dynamic, all the others are now fixed in time. (Assuming perfect knowledge of current and past conditions!) All new species will always come from existing genera, so that and higher taxa are forever fixed. Note that existing higher taxa (above species) can only decrease with time, since some may die out. Also, these curvey lines would nicely show that if a lower taxa (such as species) crosses back over (lower in time) a higher taxa (such a genera) that a problem needs correction. Botanists do this sort of shifting periodically.

The only way to get more of anything other than species is to agree to shift the curves higher in time. Imagine if everything other than insects died out in the future, then the current insect orders (with their diverse body plans) could be the "new" phyla but that diversity would have arisen much later than our current phyla.

BTW, if in the distant future all living species are descendents from insects, then they could argue over the Upper Carboniferous "explosion" and the sudden appearance of the "living phyla" that appeared at that time.

The point used to be made more frequently, but opponents of Darwinism tend to be metaphysical essentialists. That remains true of old earthers and ID types as well. For them, the phyla correspond to distinct, unchangable essences. Nevertheless, by claiming that all the creation occurred just before the Cambrian and that the developments that took place later are merely superficial modifications (accidents in Aristotelian lingo), the ID folks have already giving up ground since more traditional Creationists claimed that it was the genera that embodied eternal natural kinds.

Excellent.

But needs a little copyediting.

Yes, I am as usual a bit hasty in my releases. So much to do and such little time

metaphysical essentialists

I don't mean to be mysterious by using the expression "metaphysical essentist." I was referring to the belief that members of the same species (or genus or phyla or any other natural grouping) share a form or principle that makes them what they are and that this essence is not just a name imposed on more or less similar beings by observers but an objective reality. This way of understanding things is very old---one usually associates it with Plato and Aristotle---but it's still around, not only in discussions of evolution but also in debates about abortion and other places. If a living thing is a living thing because it has "life," it's hard to see how it can come into being out of lifeless matter since anything whatsoever either has or does not possess this characteristic. I think the same logic makes it hard for Creationists to deal with the idea of transitional forms. For example, being half way between a reptile and a bird strikes 'em as an odd notion, rather like claming somebody is sort of pregnant. Likewise, every fertilized egg has a soul because to believe otherwise would involve believing that our humanity is something that can come to be little by little through a natural process.

By the way, like Steven Jay Gould, I have no personal problem with the notion of essences per se, just the reified, metaphysical version of the concept. Cats really are catty, i.e. they have a suite of characteristics that hang together and persist from cat to cat and even from species of feline to species of feline because natural selection has happened upon a collection of traits that works. By my lights, the essences of the so-called natural kinds are results rather than causes.

Ah. Thanks! Don't you think that all those fundamentalists are going to feel a bit foolish when they realize they're just Platonists after all?

Yeah, unless Plato was right!

The links to Michael Benton in Biol. Rev. (2000) are broken, try this.

Thanks updated the link. Good paper...

Meh. Not a good paper, really.

Check out Bryant, H. & Cantino, P. 2002. A review of criticisms of phylogenetic nomenclature: is taxonomic freedom the fundamental issue? Biological Reviews 77: 39-55 for an excellent response to Benton (and a host of others).

My favorite thing about the graph of "Dawrinain predictions" at the top is how it shows the number of phyla increasing exponentially, and then for some reason hitting an inflection point midway through Earth (or post-Cambrian) history. After that magical point, the number of phyla increased much more slowly until it leveled off sometime around the Pliestocine.

Apparently, the Earth was much empier back during the age of the dinosaurs, which should have encouraged the evolution of new phyla, but since then it's "filled up" and no new phyla can evolve. What geniuses come up with this stuff?

That's the point of my first post. Why is it a logistic curve? The deepest ID 'science' is just hand-waving.

In the parlance of our times, they got nothin'.

Hi God Fearing Atheist. I am interested why you do not like the paper?

Another interesting link to some of the same material.