Good teachers are so very rare that it's worth mentioning. This was Henry Margenau, who died only very recently. He lived to be 97 or something like that. And he was a very good teacher. He taught a course that was called something like Philosophical Foundations of Physics or something of that sort, I forget the exact name, but... through calling it philosophy he was able to present very advanced material, which otherwise might not have been considered suitable for sophomores or juniors or whatever.

[Q] Was that… he wrote this book Nature of Physical Reality...

Well, that was later...

[Q] Which was later, but it..?

...this was Margenau and Murphy… no, was it? Wait a minute, was it..?

[Q] Margenau and Murphy was the Mathematical...

No, that was Mathematical Method, so it wasn't that...

[Q] But he had written this book later and I wondered if that…

Maybe it was Margenau…

[Q]… that sort of was the text...?

…maybe it was Margenau. I really can't remember whether it was by him alone or by him and Murphy, but either way what happened… the way the course went was the following: he would say, ‘Now, we’re going to do… right at the beginning… we're going to do Lagrangian and Hamiltonian mechanics. Now, you all know the calculus of variations, don't you?’ And everybody looked blank. And he said, ‘Well, they haven't taught you the calculus of variations? What do they do in your math classes? They must waste your time with epsilons and deltas. Why don't they teach you the calculus of variations? I can't understand’.

[Q] He is a man after our own hearts!

Of course, exactly, exactly. ‘Can't understand why they would waste your time with that stuff instead of teaching you the calculus of variations. Well’, he said, ‘It's not a problem. On Tuesday we will learn the calculus of variations, and on Thursday we will begin Lagrangian and Hamiltonian mechanics, and we'll do it on Thursday, Saturday and the following Tuesday’. Something like that, and that was plenty. And he did discuss the philosophical foundations. For example, he showed us how the principles – the principle of least time, the principle of least action, and so on – were… appeared to be teleological, the physical laws appeared to be teleological, they appeared to be heading toward the objective of satisfying the principle of least action and so on. But, he said, since they're mathematically equivalent to Newton's differential equations, now there is no problem. They're not teleological, they are in fact just progression from one instant of time to the next. And by bringing in these very simple philosophical lessons he stuck to the promise of the course while actually telling us a lot of very interesting material about actual physics. Then he went on to the next subject, which was… well, I don't know, he covered many subjects, but one of them was special relativity which took, I think, two days, and then general relativity. And when he got to general relativity, he asked the same question, he said, ‘You all know tensor analysis, I assume’. We said, no, we don't. He said, ‘Well, what do they do in those math classes? Why don't they teach you tensor analysis instead of all those stupid epsilons and deltas?’ And he said, ‘Well, that’s not a problem. Tuesday and Thursday we'll do tensor analysis and then we'll do general relativity’. And that's exactly the way it worked, and general relativity took only a few days, and he made some wise philosophical remarks about general relativity as well, while teaching us the actual stuff, the actual equations. And then he went on to quantum mechanics and he did the same thing with quantum mechanics. He said, ‘I assume you know Sturm-Liouville theory?’ We said no. He said, ‘Well, what do they teach you in those math classes?’ Then he said, ‘No problem, we'll do Sturm-Liousville theory, and then we'll do vector spaces and then we'll do quantum mechanics’. And that's what he did, and he showed us wave mechanics and matrix mechanics and how they're equivalent and so on, which was very nice.

[Q] So he gave… he gave a complete survey basically, of all the...

… of the advanced ideas of modern physics…

[Q]…modern physics..?

…of the advanced ideas of… well, he didn't do quantum field theory or, and he didn't cover peculiar particles like the neutrino, anti-matter. Those were the things I read about in science fiction stories. That was another entrée by the way, through reading science fiction I became acquainted with the idea of anti-matter, which my courses never discussed. And neutrinos...

[Q] Do you mean at Yale you never learnt about anti-matter… no one taught a course about Dirac and..? Interesting.

And I asked the graduate students whether they had ever heard about neutrinos or anti-matter, and they said no. But of course, Yale was a backwater.