Marvin [Minsky] was an extraordinary teacher and a great mentor. And in fact really most of the people who became the heads of AI labs and leaders in AI were Marvin's students. And it was for a few reasons. Partly he was fun and he was funny. I remember once walking into his office and he would just roll up a piece of paper and he threw it into the trash can and he overshot the trashcan, like, way overshot it. He looked confused. And then he said, 'Oh, it's one half inches squared.'

But he always had... But he always had a kind of intellectual generosity. He was always happy to explain things. And he believed something... He taught me something which is you don't understand something unless you understand it in more than one way.

So I remember once when I was an undergraduate, I discovered... I found out about this thing which all MIT students get fascinated by which is if you take i, the imaginary number, and you raise e to the power of pi times i, it's equal to negative one. So sort of all of these magic numbers somehow come together in this amazing way. And I walked into him as a freshman having discovered this, and I said, 'Why is this true Marvin?' And he explained it to me in terms of the imaginary plane and sort of geometrically and I felt like I totally understood it. I said, 'Oh, thank you for explaining that.' And he was like, 'No, you don't understand it because you only understand it one way. Let me show it to you another way.' And then he used Taylor series and Taylor expansions. And showed it to me a completely different way and caused me to understand it a different way. And only after he'd explained it a few different ways do you really see, well, it sort of has to be true because you look at it from every angle and it's true.

But that kind of generosity as a teacher, not just answering my question but answering in a way that connected up all these different things, that was very typical of Marvin. And he would always challenge you of what you thought and he always loved it when you would challenge him or contradict him. So I would spend so much time arguing with him. And he really taught me to think. Much more, you know, I think literally true. He taught me to think.