"Is throwing out a lot of straw about predictions inviting the Egnors to make straw men?"

Commentor steven johnson on Steven Novella's blog Neurologica has a perceptive overview of the 'predictive power" of Darwin's theory.

Novella argues that my skepticism about Darwinism's "prediction" of the link between birds and dinosaurs that Novella had touted is misguided. Novella repeated his hysterical claims about the amazing power of 'things change and survivors survive' to predict the future. He admits that Darwinism predicts nothing specific about the bird-dinosaur link, except that some links should be found between some things, whenever, whatever. Potent theory.

He also makes no comment about the obvious inference that if the discovery of 'links' is evidence for Darwinism, then the failure to discover links is evidence against Darwinism.

There are virtually no 'links' at the species level-- millions of species-- in the fossil record. This lack of evidence for speciation is the explicit basis for the theory of Punctuated Equilibrium-- the theory that speciation occurs "off" of the fossil record, in tiny peripheral populations, that are invisible to paleontology. Punctuated Equilibrium posits that fossil evidence for speciation will never be found, which will count as evidence-- for Darwin's theory.

Evidence in favor counts. Evidence against doesn't count. Absence of evidence is evidence. Such is evolutionary science, 2012. You have to admire the audacity.

I'll try to respond to Novella's post in detail when I can, but commentor johnson's post is coherent and thoughtful, and worth spending some time with.


steven johnson:

Yes, Egnor erected a straw man, then still got confused while attacking it. But some of the confusion seems to be about prediction, testability and explanation.

The requisite 'Egnor is an idiot, but...' used by dissenters on Darwinist sites.

The principle of common descent would in another time or field of science would probably have been called a “law.” Scientific laws are commonly described as descriptions or generalizations about how things work in nature. Common descent was established on a mass of observations from morphology and embryology, and later confirmed further by genetic data.

Common descent is a problematic theory.

Scientific laws may be refined or possibly even wholly refuted by later observations. For instance, lateral gene transfer in bacteria seems to justify a refinement in the doctrine of common descent.

Lateral gene transfer is a proposed explanation for genetic evidence that casts doubt on universal common descent. Perhaps the genetic evidence is explained by lateral gene transfer, or perhaps common descent isn't true. Those would be the obvious scientific inferences. The Darwinist inference is to find an explanation-- any explanation will do-- to salvage the theory.

There are antecedents to this principle, for instance, the cell theory, which implicitly requires that all changes in descent be physically possible for cells to carry out. And there are consequences too, such as that new species must come from old species. But is it really useful or enlightening to call these predictions?

The inference to common descent is supported by some evidence, and weakened by other evidence. Common design or common teleology is consistent with some of the evidence now invoked for common descent.

In my view, the strongest evidence for common descent comes not from Darwin but from Pasteur, who was the greatest biologist of the 19th century. Pasteur destroyed the theory of abiogenesis, making it much less likely that life would arise de novo multiple times. Although Darwin hypothesized common descent, it was Pasteur who did the real science that made the theory of abiogenesis untenable and rendered multiple new arisings of life less likely than had been commonly believed.

Darwin worship obscures the good science that was going on in the 19th century, exemplified by Pasteur and Mendel and Ehrlich and Lister and Schleiden and Schwann and Remak and Virchow and Weismann and Koch, all of whom made actual contributions to biology in germ theory and genetics and cell theory that eclipsed Darwin, who besides authoring a few trendy books for lay audiences, specialized in the categorization of barnacles.

Natural selection, on the other hand, is what some would call a theory, a scientific explanation, although I gather others would define “theory” as an algorithm (or verbal/conceptual equivalent) for generating predictions.

If a theory makes no testable predictions, how can it be science?

What "predictions" does natural selection make? What is the evidence against it? Is it the only scientific theory supported by all evidence?

In that case, this link says that Popper’s claim is that natural selection, equating adaptation to fitness, is non-predictive because all organisms must be adapted to their environments, else they would be extinct.

Correct.

The [Darwinist] rebuttal is that 1) the unfit are extinct 2) physically impossible changes will not occur along the chain of common descent and 3) new species descend from old species. 

Note that 1) is merely a restatement, not a prediction while 2) & 3) are trivial “predictions,” because they are not unique to the theory of natural selection.

Correct.

At this point, the link goes on to explain that fitness is defined causally, functionally, statistically a posteriori, not logically and semanticaly a priori.

Fitness is defined as survival. Fitness has no logical or a priori cache. If it survives (reproductively), it was fit. If not, not.

And besides that, fitness is not determininistic but dispositional. What is not clear is how fitness being those things makes it possible to make predictions. There have been a number of experiments that have successfully tested predictions about natural selection’s effects on gene frequencies but it seems that the difficulties in defining fitness in a way that you can predict/control makes them the exception rather than the rule in evolutionary science. 

The thing worth thinking about, is that Darwin provided masses of evidence in favor of natural selection decades before experiments that teased out a prediction could be performed. Science since has provided masses more.

Apologists for Darwinism who have reservations about the theory have an amusing rhetorical tic. They express the reservation, usually something obvious-- "fitness is not deterministic but dispositional. What is not clear is how fitness being those things makes it possible to make predictions."

They immediately follow the quite correct critical observation with 'Darwin was a genius of course and was right about everything'-- "Darwin provided masses of evidence... science has since provided masses more."

'Comrade Lenin wasn't precisely right about the State withering away... but he provided masses of genius since proven right by all science..."

When you are in the Darwinist congregation and you sing the wrong hymn, you need to make penance and lay an offering on the altar. Before you leave the church.

But they weren’t predictions.

Correct, Comrade. But Darwin sure provided masses of evidence...

You can use natural selection to explain vestigial organs. An organ is no longer adaptive, nature selects agains the waste of resources for it. The mechanics of genetics may not permit an easy way to simply erase the organ, but the slow increment of genetic changes diverts resources from the less fitting organ, it gets smaller and smaller, that is, vestigial. As the resources diverted become less cumbersome, however, the intensity of selection pressure becomes less and less. The vestigial organ can then survive indefintiely until the vagaries of genetic change do possibly succeed in erasing the last trace. 

Natural selection (particularly gene-selection) says traits are adaptive, increase fitness. We can explain fitness-decreasing vestigial organs as above, using supplementary hypotheses and contingencies that explain away the violation of this prediction.

Nice story. Darwinism has all sorts of stories.

We cannot predict which organs will become vestigial; we cannot predict which will finally disappear; we cannot predict for which a new function might be found; we can not statistically predict incidence of vestigialization, time for vestigialization, rates of vestigialization or intensity of natural selection against vestigial organs.

Darwin's theory can't predict which organs will become vestigial. So how does it explain why organs become vestigial?

But, rather than throw up our hands, isn’t the real clarification, not that natural selection is scientific because it is predictive, but, because it is explanatory of massive amounts of data.

Darwinism explains everything and predicts nothing. Name the other scientific theories that explain everything and predict nothing.

Charles Darwin made a convincing case for natural selection before the experiments. And the kind of evidence he presented has only been added to.

Natural selection can be understood in three ways:

1) A tautology
2) An acausual statistical inference about changes in gene frequency
3) A causual assertion as to how evolutionary changes occur.

Which definition of natural selection is buttressed by the evidence?

Even more to the point, if there are experiments confirming predictions of natural selection about speciation (instead of change in gene frequencies,) they are a well kept secret.

Refreshing honesty. Evidence for intermediate forms between species in the fossil record is virtually absent. For millions of species.

I suppose it is likely that eventually science will find a way to conduct such experiments.

Until then, is it ok if we just say that Darwin's theory of speciation isn't supported by the evidence?

But even if no one were ever ingeniuous enough to find the way, we already have quite a bit of evidence showing that natural selection is a major factor in novel speciation,

Speciation is very rarely observed, except in novels.

and overwhelming evidence it is the major factor in maintaining species morphology (the forgotten aspect of speciation?)

"Maintaining species morphology" means net absence of evolution. So natural selection is 'the major factor in maintaining the absence of evolution'.

You have to admire the gall.

Is throwing out a lot of straw about predictions inviting the Egnors to make straw men?

Johnson understands something Novella doesn't, aside from the science. He understands that the hyperbolic paeans to Darwin-- predicted everything, indispensable to biology, the basis for all medical research, the best idea anyone ever had, on and on-- don't advance the ideology. Darwinism is best served by indoctrination and silence. Ask questions in school, Darwinists don't argue. They call the police. As questions in academia, Darwinists don't debate. They ruin you.

Praise Darwinism effusively, and people will ask-- did it really predict that? Is it really indispensable to research? Isn't there any evidence against it?

Hagiography endangers Darwinian orthodoxy. Hagiography exposes Darwin's theory to scrutiny, which is the one thing it cannot withstand.