Defining philosophy

Philosophia ars vitae est!

For a more contemporary perspective, you might want to look at the captions to Steve Pyke's photos of philosophers.

When we honestly challenge our beliefs and respond to challenges to our beliefs we are practising philosophy. The beliefs you "end" with are your philosophy.

(Honestly is my unsatisfactory substitute for rationally which I wanted to avoid.

Is there such a thing as philosophical knowledge or is knowledge knowledge? A belief can be irrational, but surely there is no such thing as irrational knowledge. I raise this because it seems to me that one cannot acquire knowledge from philosophy, though I wonder what Socrates and Descartes would say to that.)

It is asking "What is this?", "Why is this?", "How is this" and "Who is this?" and "This" can be anything including you.

The art of constructing a rational argument around one's pre-existing beliefs and intuitions...