"The degeneration of philosophical schools in its turn is the consequence of the mistaken belief that one can philosophize without having been compelled to philosophize by problems outside philosophy...
Genuine philosophical problems are always rooted outside philosophy & they die if these roots decay...
These roots are easily forgotten by philosophers who 'study' philosophy instead of being forced into philosophy by the pressure of nonphilosophical problems."

--Karl Popper, Conjectures & Refutations, (pages 95-97)