'Why is philosophy important?'

An interesting set of contributions, some by well-known philosophers, over at Weinberg's blog.  I didn't read them all by any means, but in skimming I didn't see anyone consider the possibility that philosophy is not important, but perhaps pathological.  While I'm sympathetic to Nietzche's view, I do think philosophical training serves a valuable purpose:  it is training in what I've called discursive hygiene, i.e., in being able to reason and think carefully and, to a lesser extent, argue (philosophy pays too little attention to rhetoric ever since Plato's successful defamation of the Sophists, so it is not as helpful in teaching argument as it might be).