 This history of science video will be on a somewhat specialized topic. Why did Aristotle think that women have fewer teeth than men? This question has become something of an internet meme used to mock Aristotle. So whenever there's a site that doesn't approve of Aristotle very much, they will always bring up this fact that Aristotle thought that women had fewer teeth than men, sometimes used to show how women were oppressed in those days, although exactly how you oppress people by mistaking their number of teeth I've never quite managed to figure out. This may be started by Bertrand Russell. So Bertrand Russell mentioned Aristotle's views on women's teeth several times in his writing. For example, in his book The Impact of Science on Society, he said, Aristotle maintained that women have fewer teeth than men, although he was twice married, it never occurred to him to verify this statement by examining his wife's mouths. Okay, well, that's very amusing, but if you think about it a bit, you'll notice there are several things that are a bit fishy about Bertrand Russell's claim. So we can ask the following questions. First of all, if Aristotle didn't look, where did he get the information from? Did he just look atop on the internet or whatever the equivalent was in those days? This seems unlikely because Aristotle was one of the earliest and greatest observational scientists and one thing he was really good at was making enormous numbers of observations. The second question that occurs to me is, did Bertrand Russell examine any of his wife's mouths before saying Aristotle was wrong? Well, I don't know, but he certainly never mentioned he did, and who knows? The third question is, did Bertrand Russell check what Aristotle actually said before claiming that Aristotle was making a stupid mistake? And here, he definitely didn't. So let's have a look and see what Aristotle actually wrote. I think I'll zoom in a bit so you can read it. So here is the section on women's teeth. You see, Aristotle says, males have more teeth than females in the case of men, sheep, goats, and swine. Okay, that seems clear enough. Aristotle really did say that men have more teeth than women. But then he goes on, in the case of other animals, observations have not yet been made. Okay, well, that very strongly implies that Aristotle did observe some woman's teeth, or maybe he got his research student to do it, who knows? So why did he get the answer wrong? Well, nobody really knows. The most obvious guess is that it's something to do with wisdom teeth. So some people don't get wisdom teeth at all or get them very late, and maybe whoever Aristotle checked didn't have wisdom teeth. Well, probably not, because if we go on a bit, we see that Aristotle knew all about wisdom teeth. He says, the last teeth that come in man are molar, so-called wisdom teeth, in the case of both sexes. So he knew women get women teeth, he even mentions cases that have been known in women upwards of 80 years, where at the very close of life, the wisdom teeth have come up. So the problem probably wasn't caused by women's teeth. So what went wrong? And the answer is, we don't know. Could have been anything. Maybe the woman he checked had missing teeth, maybe someone just miscounted, maybe he just made some strange copying error. Why didn't he double check and correct it? Well, obviously he just didn't think it was terribly important and had better things to do with his time. So while Aristotle was wrong, this was not because he failed to make observations, as Russell claimed, but because he did make observations and something went wrong. So Aristotle wrote thousands of pages in which he recorded huge numbers of observations, and of course the odd mistake crept in. The widespread idea that he didn't do experiments and just made things up is just nonsense. As anyone who's done experiments knows, it's all too common for experiments to go wrong for random stupid reasons, Bertrand Russell was not an experimental scientist and just may not have been fully aware of just how often things go wrong because of minor accidents. So to summarize, while Aristotle did make mistakes, he didn't make stupid mistakes. And anyone who thinks he made stupid mistakes is making a sort of second order stupid mistakes by failing to realize that Aristotle was not a fool.