A very entertaining lecture from 1991 [click on the PDF button] (which I learned about via Phillip Bricker's recent review of materials from Lewis's Nachlass). The lecture contains a crisp statement of Lewis's "conservativism" in philosophy, which is characteristic of most of the Anglophone discipline:
I am a conservative philosopher. Fear not, I don’t mean that I make it my business to glorify the marvellous market and the Republican Party!—What would that have to do with resisting innovation? One thing I do mean is this. I think philosophy has no business challenging the positive convictions of common sense, and no business challenging established results of the natural sciences and mathematics. What should a philosopher do if he discovers a proof that he is the pope? Boldly follow where argument leads?—No, or not unless he’s the philosopher Karol Wojtyła. Instead he should find the flaw in his proof. If he fails, he should conclude that the proof has a flaw he cannot find. The same goes, say I, if a philosopher discovers a proof that some truths are also false; or that motion or time or value or consciousness or freedom is unreal; or that it is unthinkable that anything exists outside the mind, or outside the text; or that there are no people, and no swizzle-sticks either; or that it is a wide-open scientific question whether anyone has ever believed anything; or that Cantor’s diagonal argument was fallacious; or that we make worlds with words. We should know a reductio ad absurdum when we see it! It is ever so much more likely that a philosophical argument has gone astray than that any of these things is true.
Gramsci's view of "common sense," and his reasons for skepticism about it, seems to me more plausible.
I did find this dig at Rorty and Wittgenstein amusing (and I'm sympathetic to Lewis's view on this score):
I am conservative in another way: I oppose revolutions in philosophy. Weare plagued by them. Their message is always: Stop it! Put down those tired old questions about mind and body, knowledge, value, freedom, universals, and all. Don’t answer them. Transcend them, debunk them, shake free of them! And then we get some story of how all that bad old philosophy rests on a mistake: how we tried to transcend the limits of experience, how we were bewitched by language, how we aspired to mirror nature, or what not. To me those stories never ring true. The great questions of philosophy, and a host of subordinate questions, are well-posed. Nobody says we have to be curious about them, or anything else for that matter; but if we are curious, we should carry on investigating them. We should try to ignore the interruptions from the stop-it brigade. And we should try not to forget discoveries from before the latest interruption.
Feel free to comment on other parts of the lecture you found interesting, amusing, provocative.