VOX DEI BATE #5

Time prevents me from a full comment on Vox's most recent set of observations. I look forward to his discussion of my previous post, which compares two predictions concerning whether intermediates to modern whales would ever be found in the fossil record.

In the meantime, Vox writes:

"....we should have no problem finding one or two and demonstrating that they are a new species that did not previously exist, assuming that this is, in fact, happening."

It's been done, by Dobzhansky's group, in the early 1960's: you can read about it here. There are other examples, though the literature in this case is not as deep as the pallid piles of papers in Keynesian macroeconomics which seem to trouble Vox. That's because it's clearly science, and real science is hard.

(UPDATE)

Now, again, (and Vox has acknowledged that this is valid, I think) I don't want to get sidetracked in a 'turf war' between economists and biologists, because it's in no way central to the topic. But Vox is at pains to explain, based upon his experience, the relevance of the comparison in his original argument:


From what I've seen of evolutionary projections, its margin of errors are even greater than those seen in macroeconomics. Since this level of inaccuracy causes me to dismiss macroeconomics as a science, it leads me to similarly dismiss evolution. Obviously, if it can be shown that the macroevolutionary margin of error is smaller than that of macroeconomics, I'd be happy to reconsider. (my emphasis)

I think there's a basic error here: the map is not the territory! Vox is not arguing here that the theory of evolution by natural selection (TENS) has been falsified generally. Rather, he's saying that 'evolutionary projections', models based upon TENS, have a relatively low precision, which presumably leads to a certain level of inaccuracy. Well, that's true for a lot of things in science, not just specific models based on TENS. A high margin of error is not sufficient to disqualify a research program as unscientific, however, unless it can be shown that a different research program based upon a different model has a lower margin of error.

An example from the history of science should make this clear:

Johannes Kepler, like those astronomers who came before him, began with the belief that planets moved in perfect circular orbits. Problem: this hypothesis didn't fit the data, notably the 'wanderers' (planetai) that seemed to change direction. Like Ptolemy before him, Kepler trusted in epicycles, 'wheels within wheels' that would preserve the hypothesis of perfect circular motion. These models worked with a certain margin of error and, for most heavenly bodies, the discrepancies were so small once the epicycles were added that most felt they could be ignored---except, in Kepler's case, for the orbit of Mars. An exhaustive series of calculations based upon the best data available (Tycho Brahe's observations) led to a closer fit to the Ptolemaic model, but still with a certain margin of error that Kepler found unacceptable:


If I had believed that we could ignore these eight minutes, I would have patched up my hypothesis accordingly. But, since it was not permissible to ignore, those eight minutes pointed the road to a complete reformation of astronomy.

So, by analogy, Vox is in a similar predicament to Kepler at this stage of analysis. He's unsatisfied with the error rate, and---feeling confident (perhaps overconfident) that he's got the best data available, concludes there must be something wrong with the model. But was that really enough to unseat Ptolemy, whose properly-tweaked model still gave better 'predictions' than any other model up till that time? Of course not! Kepler was obliged to propose another model and show that it gave better results, with a lower margin of error.

Which he did, one based upon ellipses rather than circles, and in the process Kepler discovered some generalizations about the behavior of heavenly bodies which presaged Newton and which have since been described as his 'Laws of Planetary Motion'.

But the story doesn't end there! Both Kepler's Laws and Newton's Law still maintain a certain margin of error, albeit one lower by several orders of magnitude than, say, geocentric solar systems or Archimedes' statics. But the existence of these discrepancies did not automatically lead either of the former constructs to be rejected as science! These 'Laws' came to be seen in the 20th century as limiting cases of Einsteinian mechanics, whose margin of error becomes significantly lower at certain scales. In fact, no one would've been willing to embrace Einstein's thought, with all of its counter-intuitive moves, had there not been a 'trade-up' in precision!

So, Vox, you can play the part of evolutionary skeptic all you want to, but you can't expect the scientific community to join you in rejecting TENS on the grounds that you've given (its high margin of error) unless you can do what Kepler did and propose a testable explanation whose margin of error is significantly lower.

Now, Vox, I am guessing that you don't reject Keynesian macroeconomics out of spite or prejudice, but that you honestly feel that there are other models that do a better job of predicting economic behavior. That's not my bag, and again I'm disinterested in provoking a 'turf war.' What I want to know, Vox, is if you or anyone else has a better explanation for the history of life than TENS, a model that yields falsifiable predictions that, when observations become available, have a lower margin of error than TENS. Because, if you can't, then your skepticism remains an intuition, rather than sufficient grounds to reject evolutionary theory as science.