Why is philosophy difficult to define?

Why is this question so compelling? (to someone, anyway)

Charles Taliaferro posted a thoughtful answer/challenge to the same question just three weeks ago:

http://askphilosophers.org/question/24944

Another (and very different) response, to yet another iteration of this same question on this site, is here.

Read another response by Stephen Maitzen, André Carus
Read another response about Philosophy, Language