On Old Age

When forty winters shall besiege thy brow

I borrowed The Third Chimpanzee by Jared Diamond for this task. (Public libraries are wonderful institutions.) I have already read his Guns, Germs and Steel, and I figured this would be more in the same vein: informative, eye-opening and amazingly wide-ranging. And the first 50 pages have been just that. For instance, I knew the family tree of primates had humans being at the top or at the very end, as the pinnacle of evolution.

But it can also be drawn like this:

According to Diamond, writing in 1992, share 98,4% of their genes. (A later number is even higher, 98,8%.) Gorillas, on the other hand, share around 97,7% with both chimps and humans. In other words: Our closest relative is the chimp, but also the other way round: the chimp's closest relative is humans, not the gorilla. The difference between the bonobo and the chimp is 0,7% — and they are so similar that they were “discovered” to be two unique species as late as 1928.

To put it into perspective, the Willow Warbler and the Common Chiffchaff share only 97,4% of their genes, even though they look quite similar to an untrained eye. (The same is true of Red-eyed and White-eyed Vireo: 97,1%, according to Diamond.)

Perhaps you, like me, don't know these birds at all. And now, 20 years later, there are probably more and better examples. But Diamond's point remains: we, humans, are just a primate, we're just one of three chimps, and if an alien came to earth, he would lump us together in one genus. We are Homo sapiens, the chimps are Homo troglodytes, and the bonobos are Homo paniscus. The alien might even include the gorilla in this classification.

Evolution isn't towards a goal. Humans are not the apex of evolution. The first image above implies that: why should humans be at the left? The second image, however, shows humans as just one branch o par with every other branch.

I knew that. And yet I didn't know that, didn't think things through. Imagine going to a zoo, for instance, where there are two cages next to each other: one with naked Homo troglodytes, and one with naked and for some reason speechless Homo sapiens. The difference seems almost negligible, doesn't it?

That's what Jared Diamond does. He expands your knowledge even where you though you knew a lot. A put him on the hero page.

But some pages later he seems to argue against one of my other heroes and deeply held beliefs. He says that early Homo sapiens probably didn't hunt that much, and much of their calorie consumption came from plants, berries, fruits, nuts gathered by women. Occasionally, the men caught a rabbit or smaller prey, but the larger prey remained mostly stuff for late night bragging stories around the fire. In Papua New Guinea, where Diamond has been many times, this is the case.

My other hero is Daniel Lieberman. (He will be 50 this year. He is old enough to be old.) According to him, persistence hunting was one of the main reasons, if not the main reason, for how the human body evolved. Many of the main differences between us and apes can be explained by our hunting: we sweat rather than pant, we are bipedal, our feet are much better suited to running than climbing trees etc etc.

Lieberman is one of the scientific gurus of barefoot runners, and as such, I feel quasi obliged to agree with him. And based on YouTube clips, he is a really nice guy, likeable, the way I want to be nice and likeable when I grow old. And his research is newer and more specifically about evolution of humans. And he has a white beard (albeit short).

But I cannot and should not choose, at least not now.  I don't know enough, not even halfway to knowing what I'm talking about. They might even disagree on some minor points.

And anyway: having a hero for your old age is not about following someone blindly. It's about seeing how strong your character strengths can be. And if anyone is curious and open-minded and shows a love of learning, Lieberman or Diamond or anyone else, he will change his beliefs as evidence propels him to.

That might be the definition of open-mindedness: no belief is sacrosanct.

I'll read more of Diamond. I'm certain he will have changed dozens of my beliefs by the time I have finished his book.