Darwin’s Blind Spot

I constantly run across people who tell me, “I’m just following the evidence.”  That phrase is supposed to convey that the person is detached from the inquiry and is weighing everything objectively.   Yet “evidence” is not truly objective.  Data and facts, detected by the senses, are objective.  To transform that raw data into “evidence” requires the mind’s eye.  That is, the evidence is interpreted in light of previous beliefs and experiences, and the mind tries to make sense of the data with an explanation.  Once the explanation is born, the data become evidence as part of a top-down process.  So because evidence is firmly rooted in perception and the mental realm, “following the evidence” is not completely different from following your dreams or following your intuition.

A clear example of how one’s mental template can blind them from seeing the data as evidence, one need only consider Charles Darwin himself.  Consider these excerpts from a Science Daily article:

Mendel solved the logic of inheritance in his monastery garden with no more technology than Darwin had in his garden at Down House. So why couldn’t Darwin have done it too?

Great question!  So what’s the answer?

A Journal of Biology article argues that Darwin’s background, influences and research focus gave him a viewpoint that prevented him from interpreting the evidence that was all around him, even in his own work.

How so?

Darwin’s commitment to quantitative variation as the raw material of evolution meant he could not see the logic of inheritance, argues Jonathan Howard of the University of Cologne, Germany.

“Quantitative variation was at the heart of Darwin’s evolution, and quantitative variation is the last place where clean Mendelian inheritance can be seen,” says Howard. “Darwin boxed himself in, unable to see the laws of inheritance in continuous variation, unable to see the real importance of discontinuous variation where the laws of inheritance could be discerned.”

So why was Darwin so hyper-focused on continuous variation?

Darwin’s view of biology was greatly influenced by geologist Charles Lyell during and after the 1831-1836 Beagle voyage, leading to Darwin’s focus on infinitely tiny differences between individuals giving infinitesimal advantages or disadvantages in survival. For Darwin, selection of these variants over hundreds of thousands of generations was the critical process in evolution.

And there y’go!  We have seen that Darwin’s focus on strict gradualism not only emphasized the strongest expression of non-teleology, we’ve seen that it caused him to be blind to the challenge posed by the results of artificial selection, and we have seen how the emphasis on strict gradualism has misled generations of evolutionary biologists.  Now we can add something else – the focus on strict gradualism prevented Darwin from perceiving the breeding data as Mendel was able to see it – as evidence for discontinuous variation.

3 responses to “Darwin’s Blind Spot

  1. Darwin observed that every (?) trait he measured varied continuously, and continuously varied, and that under certain conditions (including a system of inheritance) such continuous variation was heritable, and cumulative continuously. It may be that his focus upon continuous variation misled him, but as usual it’s a bit more complicated than that. On Darwin’s theory of heredity, discrete elements (“gemmules,” which Darwin identified with molecules) that varied continuously were inherited. A conception of heredity that sounds quite familiar.
    But as was noted, Darwin missed the “logic” of inheritance. And that’s a lot. He missed a lot. E.g., he didn’t notice that even though traits vary continuously, they are often inherited as discrete units, e.g., as pairs. My legs very continuously in length from each other, and from every other pair of legs, but legs are still inherited (often) as pairs and even multiples. He also didn’t notice the significance of the fact that often sexes come in pairs. And therefore didn’t notice the importance of discrete segregation. He also didn’t notice the importance of segregation in selective breeding.
    It may have contributed to his confusion, but in the first instance we should refer to what he observed. What he observed led him to the notion of continuous blending of traits.
    The lesson is that what we observe directly… Etc. Ya’ll know the lesson. It’s science.

    I think Mike Gene is hard pressed to attribute Darwin’s failure (Darwin amongst so many others) to derive the basic principles of heredity to his “non-teleological” stance.

  2. Howard attributes Darwin’s blind spot to his focus (obsession?) on infinitely tiny differences, which, as I argued in the linked essay, amounts to the strongest expression of a non-teleological viewpoint. I need to get and read the Howard paper. I did find a better review from David Tyler over at ARN (he scooped me by a year!). Also, you might be interested in the Schwartz paper linked in my previous essay (which is linked in the above essay).

  3. A lot of people think philosophy slows down science and they point to how philosophy slowed down advancements in quantum mechanics as an example. But consider the fact that Darwin’s emphasis on incremental changes slowed down advancements in evolutionary experimentation for decades.

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