Stephen Dubner (co-author of Freakonomics) asks his readers an interesting question: Who do you think is the greatest modern-day thinker? As I'm writing this, there are almost 500 answers (mostly utterly crazy suggestions, like Ayn Rand or Jacques Derrida).
The question, it seems to me, is pretty much unanswerable, and it all revolves around how you define, "greatest", "modern-day" and "thinker". But that doesn't mean I can't have a go for the hell of it... (Please don't take this too seriously).
Taking "thinker" broadly as anyone who has written non-fiction books or articles, but excluding mathematicians (who I don't know nearly enough about to have an opinion) and leaving "greatest" vaguely defined as 'making important contributions,' then...
If "modern thinker" is defined as "after the scientific revolution started in c. 1543", I'd say Charles Darwin, without a doubt. (With Newton as a close second, and Hume in the running). If "modern thinker" is restricted to the 20th century, I'd say Einstein and then John von Neumann. If "modern thinker" is only those currently living, I have no idea, it's far too soon to tell.
As I mentioned above, a bunch of commentators gave deeply silly answers. Rand? Ron Paul? Alan Greenspan? Malcolm Gladwell? Bill Gates? Christopher Hitchens? Michel Foucault? Jacques Derrida? I think not. And with all due respect to Pinker and Dawkins, they're great communicators and synthesizers of other people's ideas, but neither has made original contributions even remotely comparable to, say, an Einstein.
(Via Marginal Revolution).