Wednesday, December 16, 2009

Doing Biology Without Darwin

A student asked a good one as my Darwin class wrapped up last week. He asked, "Can you do biology now without Darwin?"

If the question asks whether one can be a working biologist without believing in speciation by evolution, the answer is a trivial yes. Evolutionary theory could be seen as a mere tool, as a working assumption believed to be false just as James Clerk Maxwell assumed molecules to be perfectly spherical and to interact only by contact in deriving his first version of the kinetic theory of heat, assumptions he knew to be wrong, but which he found useful in calculation.

But the real question is whether you could reject the Darwinian model altogether and still find research you could do in the field. This is similar to an episode in the history of mathematics. In the early 20th century, a group of mathematicians were worried by the strangeness that was coming out of Gregor Cantor's work on transinfinite numbers and so declared that mathematics must avoid infinities, that all meaningful mathematical entities must be "finitely constructable." This limitation posed an interesting question because so much mathematics relies -- or at least seems to -- on infinite processes. The questions was how much mathematics could these so-called intuitionists do and what parts are they placing off limits?

We could ask the same question about biology. Let's suppose we have a talented biologist working in a repressive country in which any research connected to evolution is illegal and harshly punished. What projects could our oppressed biologist still work on?

Step one is to clearly set out what is off-limits and for this we need an account of what we'll mean by "evolution." I propose these five axioms:

I. He has his grandfather's ears, poor thing (heritability of properties) -- offspring inherit bodily traits from their parents.

II. You are all different. I'm not (random variation) -- while children look more or less like their parents, each individual has certain random differences in bodily traits.

III. Survival of the just good enough (natural selection, clever phrase stolen from Hanno) -- some varieties are more likely to survive the struggle for existence than others and those will have more offspring.

IV. Hey, baby, are you a Pisces? No, I'm actually a fish, you moron. (sexual selection) -- those who get more dates have more offspring.

V. The species they are a'changin' (mutability of species) -- the effects of natural and sexual selection upon the variable organisms in a population will cause new species to emerge.

If we take accepting those five axioms together as Darwinism, what in biology stands outside of it for our hypothetical scientist?

As Joseph Graves points out, aging would be one place you could do biology without Darwin since anything that appears after one's reproductive years cannot be selected for. Our biologist could do work on older animals as long as they stay away from questions of why certain genetic elements that lead to, say, Alzheimer's, are present.

And that seems to be the key. We need to focus on biological questions that can be treated ahistorically. "How does" type-questions that examine biochemical reactions needed for bodily processes or biophysical questions about how bodily arrangements are able to do certain tasks would seemingly still be available.

Others? Cerainly, the pickings are slim, but how slim? What biology could our constrained researcher still do?