If you're interested in biography, perversion, and modern ideas, I highly recommend Paul Johnson's Intellectuals. I read it on my honeymoon (heh, heh), so it's been awhile, but I remember greatly enjoying the min-bios on Rousseau, Shelley, and Sartre.
I later read E. Michael Jone's Degenerate Moderns, which I liked even more than Intellectuals. Jones made explicit what Johnson implied: degenerate living leads to degenerate thinking. It's the principle of connaturality, and it's been a chair in my mental living room for many years now. I think it's one of the (smaller) reasons the sciences have flourished while the social sciences have stagnated or, indeed, gone backwards: degenerate living doesn't impair the ability to think, but the passions they arouse impair judgment. A lustful man can explain pi, but he might not be able to see why he shouldn't bed his neighbor's wife. It's one of the reasons, Eric Voegelin observed (in From Enlightenment to Revolution, if I recall correctly), why a civilization can both advance and decline at the same time, as ours has.
Here's how Joseph Epstein explains it:
Social science is vulnerable to an examination of the lives of its investigators in a way that pure science is not. Newton's religiosity in no way invalidates the theory of gravity, nor does Einstein's rather soft liberalism vitiate the theory of relativity. But in the social sciences, “every idea,” as Nietzsche somewhere says, “has its autobiography,” and that autobiography can sometimes disqualify the ideas themselves.
