Did capital punishment affect more than just morality?

February 23, 2019

This article on New Yorker is a review of a new book by Richard Wrangham. I haven’t read the book, but as far as the review goes, it offers a really fresh view on the origin of virtue and its peculiar relation to human violence.

Simply put, people today are generally less aggressive (as compared to chimpanzees) because we used to kill those who do not behave nice for better group life.

It is well-known that domesticated species evolve specific traits — some of them are morphological, like smaller body size or reduction in the size of teeth, and some of them are behavioral, like being less aggressive. We can see that just by comparing dogs with wolves. And if that is not enough, look at some very fascinating results that Dmitri Belyaev and Lyudmila Trut achieved by selectively breeding foxes over the course of 60 years.

Humans also possess traits that suggest domestication happened (reduced brain size, rounded skull shape, etc.). But there was no one to domesticate us! If no one selectively breeded us, then only natural selection can be responsible for who we are today. Yet, although violence is adaptive, human societies are very unlike aggressive chimpanzee societies.

It is believed that we self-domesticated ourselves. The book above is a take on how exactly that could have happened. The main idea seems to be that, if you execute the aggressive ones, they obviously do not get a chance to reproduce and spread their genes. Then, rather naturally, only the least aggressive remain, with all the accompanying morphological traits. And this could be the reason why humans eventually developed a sense of morality, of what is right and wrong.

Notice the paradox, that is mentioned in the review: to reduce reactive aggression in the group we had to cooperate and execute the “bad guys”, which itself is what is called proactive aggression. As the author writes,

“…coalitionary proactive aggression is responsible for execution, war, massacre, slavery, hazing, ritual sacrifice, torture, lynchings, gang wars, political purges, and similar abuses of power.”

If any conclusions can be made, it is that our moral imagination is unbounded and must be used to make progress toward equality and peace. It is just “damn hard”.

I am not in a position to decide how true this is, but when I talked about the article with my wife, she wondered whether this logic can be applied to other traits like language.

Apparently, there was a time when different Homo species coexisted on Earth and even interbred. We do not know much about the language abilities of Neanderthals or Denisovans, but it is not hard to imagine that Homo sapiens were the only ones who could speak. And even among Homo sapiens, there could have been individuals who didn’t possess the faculty of language as we know it today (which, I believe, is rather realistic). But those who did, could use it to collaborate and execute the “mute”, including other species like Neanderthals or Denisovans, on whatever reasons they had in mind. That would explain why there are none left today.

By language I do not just mean shared intentionality combined with words. The combinatory power behind creative language use also allows for complex tool-making and planning. Both could be used to create weapons and make complex pre-moral decisions about the wrongness of being unable to speak.

Maybe, as Stephen Jay Gould would say, this is a just-so story. We do not and may never have a clue about how complex psychological traits evolve, as Richard Lewontin argues in one of my favorite papers. But at least the story isn’t an entirely bad one. If we humans are capable of massive purges in 20th century, it is not so surprising we could have done it hundreds of thousands years ago, when world population was much smaller.