Yet many people, I suspect misled by Gould, have come to treat them as though they were somehow different aspects of the same thing. And that's very misleading. As though I should be worried about the phenomenon of mass-extinction, because at a superficial, poetic level it sounds like a discontinuity. Whereas I have always said that the evolution of Darwinian adaptation has to come about through gradual change. It doesn't come about through mass- extinction, it comes about in between extinctions.
Extinction has nothing to do with the production of adaptation.
That I'm very keen on, and I've often expounded that idea. From our point of view as scientists, if we could do the experiment of clearing the decks once every few millions years, it would be fascinating to do so. It would be very drastic, and I wouldn't wish to do it, but nature does do it from time to time, and so we can see what happens when you clear the decks of, for example, dinosaurs. And since you get different mammals in different parts of the world, it means that the experiment is run once in Australia, once in South America, once in another part of the world, and so you can see it happening three times over. So, certainly, 'clearing the decks' is a very important and interesting phenomenon, but it's not a selective event in the Darwinian sense.