So here we are in the ninth and penultimate post of The Hannibal Blog‘s search for the world’s greatest thinker ever. And the runner-up is…. Charles Darwin.

Darwin’s thought fits all the criteria The Hannibal Blog has laid out so far: his insight was simple and yet non-obvious and subtle (and thus still frequently misunderstood). He appears to have been right. And for good measure, his insight is also extensible, explaining far more than “just” speciation.

Simple:

Even though the details are still being debated, the core insight is so simple that I always think it borders on tautological. Those genes whose vehicles (phenotypes) are relatively better at making it to the next generation and the next and the next … are the ones you see around you today. Duh. Those genes that manifested themselves in phenotypes that kicked off too early to reproduce, or that reproduced but created offspring that couldn’t repeat the performance … are not the ones you see around you today. Duh.

Subtle:

As Geoff Carr, our science editor at The Economist, once reminded me, people often get the implications of natural selection and evolution (which is what I described above) wrong. I’m not even talking about the fire-and-brimstone creationist types. What many people infer is that evolution is somehow about improvement. (This is the seed of an entire genre of cartoons.) It is not. Instead, evolution is about adaptation. It would merrily go on if we humans were to wipe ourselves out tomorrow with a nuclear war. The bacterial slime in thermal vents would carry on unperturbed.

The other thing that people get wrong is to overemphasize the survival part. It’s the reproduction part that drives the process. Somebody once explained it to me best by saying it’s about which organisms have the most grandchildren. Ie, think of a strapping stallion and a purdy donkey. Both are great at surviving, and great at reproducing, but something in their genotype makes them choose each other. They will have lots of sterile mules. Two generations later, their genes will be gone.

Extensible:

I think the expansion of the concept really kicked off in earnest with Richard Dawkins and his idea that even non-biological systems evolve. Culture is such a system, and the equivalents of genes are idea snippets called memes. Some memes (ideas, fads, fashions) adapt, travel and spread, others do not.

The basic concept also explains so amazingly much else. Why grandmothers tend to be closer to their daughters’ children than to their sons’. Why women show a bit more skin at one time of the month than during the rest of the month. Why humans are sometimes altruistic and sometimes not. Why so many of us are religious. And on and on and on. In short, why we are who we are….

Next time: the overall winner. Once again, I promise a surprise.