Meanwhile, Richard Dawkins was picking another fight.

Normally, this would not be an occasion worthy of comment. The best way to distinguish between Professor Dawkins’ waking and sleeping states is probably on the basis of how contentious he is at a given time. Nevertheless, I’m compelled to say something for two reasons. First, this particular fight happens to be taking place right in my proverbial (and professional) wheelhouse; second, I’ve just finished my annual re-reading of Michael Crichton’s Jurassic Park duology.

That last bit requires some explanation, I know. As I mentioned in my last post, Crichton spent most of his later career playing the role of anti-establishment gadfly. For The Lost World, his sequel to Jurassic Park, he set his sights against the theory of natural selection. Indeed, the centerpiece of the book—almost literally, coming precisely halfway through the page count—is a chapter entitled “Problems of Evolution,” wherein Crichton asked the following about the evolution of human intelligence:

“... where does natural selection act? Does it act on the body … on the developmental sequence … on social behavior … Or does it act everywhere all at once—on bodies, on development, and on social behavior?”

This is an issue known to philosophers of biology as the “levels-of-selection problem” (I’ll abbreviate it as LOS hereafter). Biologists don’t have a clear answer to Crichton’s question, and so he took it to be the case that the theory of natural selection is deeply flawed. But Crichton missed an important point: that LOS is a philosophical rather than biological problem.

Professor Dawkins’ newest fight is about LOS; as it happens, so too is my PhD thesis.* I’m therefore going to take this opportunity to summarize the debate and to show that we do have decent answers to Crichton’s question—so long as we ask those questions in the right context.

Let’s start with a big question. What exactly does the theory of natural selection say, and why is LOS a problem?

There’s a reason that Thomas Henry Huxley (AKA “Darwin’s Bulldog”) responded to the publication of The Origin of Species with the exclamation, “How stupid not to have thought of that!” The reason is that the theory is, very broadly speaking, incredibly simple. It says that individuals that are better equipped for survival in their environments will leave more offspring in a population than worse-equipped individuals, and so each subsequent generation will see a greater proportion of beneficial traits in the population—and this spread of traits is evolution.

More specifically, evolution requires three things: first, that there is variability between the individuals in a population; second, that the variations can be inherited by individuals in the population’s next generation; third, that there is a consistent reason that individuals with one kind of variation leave more offspring than individuals with a different kind of variation. We can call these the requirements of variability, heritability, and differential reproduction. We can imagine these requirements combining into a sort of informal formula for evolution:

Variability(x) &; Heritability(x) &; Differential Reproduction(x) ➝ Evolution(y)