Hi Sean,

Just go your book and looking it over.

Some bg on me, I’m a ecology and evolutionary major from Princeton, later self-taught programmer. I’ve been noticing a lot of confusion on natural selection related to genetic algorithms just in general.

In general genetic algorithms aren’t based on natural selection but on artificial (human) selection. The big difference is how fitness relates to the outcome. In artificial selection you determine “fitness” a priori, that is before selection, while in evolution “fitness” really is an emergent property. It’s a little weird and that’s why evolution took such a long time to understand.

Darwin’s later adoption of the phrase “survival of the fittest” (which he didn’t coin) is probably the source of this confusion but fitness is not the determinant factor for survival. What? I know. It sounds like the exact opposite of what you’ve heard. But fitness is a property that shows up only after survival. A better way to say it would be “those that survive, tend to be more fit” A tendency that is not deterministic. Can you have the less fit survive? Well technically yes, but more importantly you have no idea what “fit” is until after selection. Remember that natural selection explains the why of speciation. Why there are many species and why they evolve not fitness. Contrast this with artificial or human selection. We breed dogs for certain qualities, we grow plants and select the seed with the qualities we most desire. Here “fitness” is determined by humans before selection, in fact, selection is based on these factors. This seems to be more closely aligned with genetic algorithms to me.

Ok getting back to the book. The following phrase “The fittest individuals are the ones that are selected to reproduce because they can pass their strong genes to the next generation.” on page 71 is technically wrong when referring to natural selection; it is correct when referring to artificial selection.

Nicely this phrase just before it “Charles Darwin’s theory of evolution suggests that strong traits that are key to survival become more common in successive generations.” is correct.

This may seem like a small thing but this misunderstanding of Natural Selection has lead to it being used as a pseudoscientific justification for discrimination in the hands of Social Darwinist, which is really just a pseudoscientific excuse to not be a nice person.

Let me know if you have any questions, happy to discuss.

– David Acevedo