Steve Sailer has posted about a subject that's fascinated me for years: why does reasoning lead to self-deception more often than to truth in most people, even when this reasoning is applied to the simplest of topics, topics in which the truth is practically lying on the surface? And I definitely include myself in "most people" here - over the years I've managed to reason myself into believing oodles of things that now seem utterly false to me. And if experience is any guide, a lot of what I believe now will seem false to me in the future, moreover, some of it will be definitely proven to be false. And of course the errors in my "reasoning" will turn out to have been idiotically simple.
Did reasoning evolve in order to help us win arguments with people or in order to help us search for any sort of objective truth?
I was quite obsessed with this topic at one time, so much so that I even included a scene about it in my sorry excuse for an unfinished novel.
True rationality, though rare, does exist, and if the computer on which I'm typing this wasn't built on cold-bloodedly rational principles, I wouldn't be able to make this post. At the end Steve wondered where and when such true rationality originated.
I may well be wrong about what follows, but I have a hunch that a lot of it originated with farming in northern latitudes. We know from archeology and from written sources that in antiquity northern European farmers lived on isolated homesteads, not in villages. When combined with primitive farming technology, the harsh climate could only feed so many farmers per square mile, so they had to spread out. In isolation, the struggle with nature must have taken precedence over struggles with other people. Nature can't be bullshitted into anything, but people very much can be.
It's interesting to note here that the north of the temperate belt of the eastern side of Eurasia was always covered with steppe, not farmland. The Yellow River valley - the cradle of northern Chinese civilization - is located roughly at the latitude of central Spain. And the nomads who roamed north of there seem to have lived in groups.
Most conscious reasoning is rationalization in support of notions we would subconsciously like to be true and which we want others to believe, usually for our own, selfish, subconsciously-determined reasons. The two are obviously linked - the most effective BSers are the ones who sincerely believe in what they're spouting. You've got to convince yourself before you can hope to convince others. It seems that BSing skill would increase one's evolutionary fitness in most social setups, with relative isolation being the only setup that could work in the opposite direction. Hence, a search for the origins of rationality would be a search for historical conditions that favored relative isolation.
I'm sure that truly rational (i.e. unemotional, unselfish, completely conscious) thought is rare in all peoples and in all cultures. However, if in one society 1% of all the men have a tendency to consciously think rationally 1% of the time, while in another only 0.1% of all the men tend to think like that 1% of the time, then differences in scientific and technological achievement would probably arise under certain circumstances. Historically these circumstances have definitely included the urbanization of formerly farming populations, but I'm sure that there would be lots of other preconditions too.