Another September, another set of classes. This fall, as for the last few falls, I’m teaching the history of economic thought. I usually start off by asking the class—20 of them in the first session this week, we’ll see how many come back for the second—why we should read Aristotle, Aquinas, Cantillon, Smith, Ricardo, Keynes, Hayek and so on.

One reason that gets a sure laugh from students is that history of thought isn’t econometrics. In our program, students choose between history of thought and a second term of econometrics. (Everybody takes one term of econometrics, after a year of stats.) No doubt some students opt for history of thought because it’s the path of least resistance. That’s OK. This is economics. We all understand “incentives matter,” as they say in Freaknomics. As economists we wouldn’t want it any other way.

Brainstorming in that first class produces a range of rationales, all of them true to a degree. By reading the classics we find out where modern economic ideas came from; get a sense of whatever progress the profession has (or maybe hasn’t!) made; become culturally or at least professionally literate; get some insight into the past; find out what the great economists actually said, rather than what people say they said (for example, Keynes was more right-wing and Smith more left-wing than they’re widely thought to have been, which is, not at all).

All that’s good, and in fact there’s no reason to insist on a single rationale for reading the classics.

My own view, which I don’t usually hear from students, is that another very important reason is humility. These days, most people suffer acutely from “presentism.” We’re all very impressed with modern gadgets, modern science, modern learning, modern ways of understanding the world. Reading the classics helps you get over presentism. You begin to understand that the best thinkers of previous eras were really smart people. We don’t have a lot on most of them.

Aristotle wrote many things we now think of as peculiar or just plain wrong. “The courage of a man is shown in commanding, of a woman in obeying.” “Some men are by nature free, and others slaves, and …for these latter slavery is both expedient and right.” But the power of his reasoning, even when it leads him astray, is truly formidable. That’s not saying anything new, of course. For 1,500 years Aristotle dominated western thought. To some extent he still does.

The same with Aquinas. I have students read his interrogatories on exchange and usury. Nowadays, with the golden rule having fallen into abeyance, at least in the world of commerce, we tend to disagree with his views of both subjects. (Exactly why we disagree is a good question for students to ponder.) But reading through his beautifully and resolutely logical presentations of the arguments, you get a sense of a mind like… I was going to say a steel trap but a steel trap isn’t a quarter of it. Aquinas has a mind like a titanium octopus—if he got you in his intellectual grip, you would never wriggle out.

Same with Smith, Ricardo, Mill, Keynes and the others. We read the textbook renditions of what these people thought, those who are still mentioned in the texts, that is, and we get a highly watered-down version of what they were about. Read them in the original, in their true distillation, and you understand that most of the objections modern analysts offer to their particular lines of thinking they themselves at least thought of and tried to answer. They are, all of them, deep, subtle, complex thinkers. They’re also often terrific writers. It’s a pleasure to read them.

Many of the young people I teach are full of their ideas and to a certain extent full of themselves, as I was at their age and as they probably should be. (Aristotle might call it youth’s true nature.) When you’re in that state it’s good to run smack into the past’s greatest thinkers. It may not teach you perspective and humility right away—I thumb through my now much-thumbed copies of the great books and cringe at the silly things I wrote in the margins when I was my students’ age. But rub up against the granite enough times and the silliness wears away.

Reading the greats is the best proof against genius inflation. When someone says some new book or article or work of art is the product of genius, as happens with ridiculous frequency these days, ask yourself how long whatever it is that’s being talked about will stand up. Will people really be talking about it 80 years from now (as we do with Keynes’ General Theory ) or 200 years from now as we will next year with Ricardo’s doctrine of comparative advantage or 240 years as with Adam Smith or, to take it to the max, 2,500 years, as with Aristotle.

It’s not a bet I’ll collect on but if anyone writes anything in 2016 that really is still being talked about all those many years from now, I’ll give them my marked-up copy of the Wealth of Nations.