ApostateAbe

Sorry, you'll have to explain what you mean. How does the common people's definition differ from mine?

spin

All this rumbling about embarrassment is just sooo embarrassing.

The criterion of embarrassment employed by people who show no interest in the context of the literature under investigation is merely projection of one's own biases. Now that is an embarrassment.

Toto

You just seem to decide you like your explanation better, so it has more explanatory power, or that your theory has a stronger predictive power of the same events.

You need to point out what facts are explained by your theory that remain anomalies under another theory.

ApostateAbe

"Explanatory power" and "predictive power" I take to be synonymous. It means that the explanation should narrowly expect the evidence. That is the principle I take to be generally accepted. Even if all bizarre theories can remove all anomalies of the evidence, at least with enough unusual and unlikely propositions, then that does not exclude one particular explanation from having explanatory power. One explanation may strongly expect the evidence, and the rival theories merely accommodate the evidence, and that is what the principle of "explanatory power" is about. If anyone else thinks anything differently about "explanatory power," then feel free to show me. For example, tell me your own idea of "explanatory power."

Toto

You can't talk about predictive power for historical models. Predictive power is tested by running an experiment and observing the results, or by waiting and observing how well the future is predicted by the model.

We only have historical data, and the explanatory power of a model generally refers to how many facts the model explains, or how elegantly it explains them.

Your idea of how "strongly" your theory predicts the data is entirely subjective.

ApostateAbe

Of course, running a test and observing the results would be ideal. But, in fields that work almost exclusively with events of the historical past that can not be repeated, then the "predictive power" of one explanation over another still counts for a lot, even if the "prediction" is only metaphorical and entirely in retrospect.

Allow me to give you an example from what I know. It is an example that I hope illustrates why "predictive power" is appropriate for retrospective evidence, <edit>.

Just a few years after Darwin published his seminal book, a fossil was discovered: the Archaeopteryx. This was a fossil of a bird that seemed to share many of its traits with dinosaurs--teeth, clawed wings, horizontal neck, long bony tail, and so on--things we generally don't see in modern birds. The evidence very much fitted Darwin's theory of evolution, and it gave much more probability to his theory through the principle of "predictive power." I don't know if Darwin or any believer of the theory actually predicted the discovery beforehand, but it would hardly matter. Darwin's theory very narrowly expects this kind of evidence, and the model of a special creation by God merely accommodates it. Several more such fossils of the Archaeopteryx have been found, and, of course, critics of the theory of evolution see no reason why the intelligent designer could not have simply specially created the bird the same as all other species, even if it does seem to share "transitional" qualities.

The phrase "predictive power" is still misleading, and that would be in part why I prefer the phrase "explanatory power" instead.

ApostateAbe

Toto, you also said, "We only have historical data, and the explanatory power of a model generally refers to how many facts the model explains, or how elegantly it explains them."

That falls under another principle that is closely related and is also important, but it generally goes by a different name: explanatory scope. That is where it is better to explain many pieces of evidence rather than just a few pieces of evidence. To be fair, sometimes, the pieces of evidence are inter-related enough that it is difficult to parse out the application of explanatory power and explanatory scope.

Toto

This was not an experiment, but it was newly discovered evidence.

You have no newly discovered evidence. You have only your own subjective evaluation of how strongly your theory explains what little evidence we have.

Juststeve

Darwin made a number of other claims in origin, about the past, which proved to be true and were explained by his theory and not the competing theories. He predicted that early man would be found to have arisen in Africa because that is where his closest relatives were found today. He expressed concern about whether the earth was old enough to allow for the development of species through natural selection. In both cases facts about the distant past were well explained by Darwin's model providing support for the model.

It is only the creation science folks who insist that Neo Darwinism is not scientific because it makes no testable predictions about the future.

Steve

ApostateAbe

I think the example illustrates why the chronological sequence of our observations of the evidence should not have much of a role in our judgments. Suppose the Archaeopteryx was discovered before Darwin came up with the idea of the theory of evolution. Do you think the "predictive power" of the fossil in favor of Darwin's theory would be any less? If you disagree, then what methodological principle in your opinion allows the fossil to be an advantage for Darwin's theory?