I know he's a boring choice, and also probably wrong about a lot of things (though that claim is complicated by the difficulty in figuring out what he really believed anyway), but Plato was by far the most effective and influential early advocate of an attitude of questioning everything and figuring things out for yourself. As such, I think he deserves more credit than anyone else for most of subsequent Western philosophy.
Hmm. At first, I was inclined to agree with you. But the more I think about it, the more I suspect that Plato and Aristotle may have had a net negative effect on humanity, if only because they were too awesome. Placing philosophy's heavyweights right at the start of its history might well have discouraged a lot of philosophical diversity, particularly since it occurred at a time when antiquity was so central to authority. This is more the case for Aristotle, since he expressed less confusion and unclarity in his arguments. But unclarity can also have a stu...
Since LessWrong is a major congregation point for certain philosophical ideas, and because people here tend to be more objective (in the sense of not being self-deluded) than elsewhere, I thought I'd ask people's views.
To be clear, by "Greatest Philosopher" I am referring not to the most correct philosopher in human history but the one who deserves the most credit for advancing human philosophy towards being more true.
Off the top of my head I would say that a prime candidate would be Hume- amongst other things he rejected the idea of a soul, realised to a much greater extent than his predecessors the limits of human knowledge, and opposed the idea that reason is somehow an objective force that can make priorities independent of emotions.
Aristotle deserves considerable credit relative for his time but doesn't make the list because although it wasn't his fault his ideas were dogmatically accepted and held back both science and philosophy later on.
Your thoughts?