Paul Graham's essay "How to do philosophy" complements this piece well: http://paulgraham.com/philosophy.html.
This:
The second event was the placing of philosophy as one more discipline alongside these sciences within the modern research university. A result was that philosophy, previously the queen of the disciplines, was displaced, as the natural and social sciences divided the world between them.
may also be a problem because the healthier parts of philosophy, concerning "Why?" or "How?", got turned into science. The less healthy parts got turned into philosophy.