Here's a story some people like to tell about the limits of reason. There's this plant, manioc, that grows easily in some places and has a lot of calories in it, so it was a staple for some indigenous South Americans since before the Europeans showed up. Traditional handling of the manioc involved some elaborate time-consuming steps that had no apparent purpose, so when the Portuguese introduced it to Africa, they didn't bother with those steps - just, grow it, cook it, eat it.
The problem is that manioc's got cyanide in it, so if you eat too much too often over a lifetime, you get sick, in a way that's not easily traceable to the plant. Somehow, over probably hundreds of years, the people living in manioc's original range figured out a way to leach out the poison, without understanding the underlying chemistry - so if you asked them why they did it that way, they wouldn't necessarily have a good answer.
Now a bunch of Africans growing and eating manioc as a staple regularly get cyanide poisoning.
This is offered as a cautionary tale against innovating through reason, since there's a lot of information embedded in your culture (via hundreds of years of selection), even if people can't explain why. The problem with this argument is that it's a nonsense comparison. Continue reading