What is Philosophy?

Because I am endeavoring to teach ideas from Philosophy to computer programmers, who typically have no background in it, a question I must answer right off the bat is "what IS philosophy?"  Here is the answer I provided to a new MOOC "Introduction to Philosophy":

Given that the single word "philosophy" is commonly used to refer to multiple different (albeit related) things, all answers to the question "Q: What is [Western] Philosophy?" actually depend on one: "doing philosophy; the act of philosophizing" which I explain to even children as:

A: Being able to answer the question, Why do you think what you think? Why do you believe what you believe?

And while you want to be able to answer to someone else's satisfaction, you foremost want to be able to answer to your own satisfaction because you want to know the truth. (BTW, the western bit is "we believe humans are capable of working it out ourselves")

All the other things the word philosophy can refer to build on, and depend on, the above. e.g. Philosophy as meaning "the body of knowledge accumulated by those doing philosophy" (which entails history of philosophy, individual ideas, individual philosophers, tools/techniques/criteria for doing it well, favorite topics for philosophizing about, etc, etc) all naturally spring from someone somewhere starting to "do philosophy".

Of course for programmers who will say, "so what does that have to do with me?", I have to quickly add that even thousands of years ago, philosophers already had come up with some really good techniques for describing the world, and being able to justify that those techniques were better than our intuition.  So, since a large portion of our work as programmers is to describe the world via our data models, object models, class hierarchies, classification schemes, etc, etc, we would get better at it if we replaced our intuition with techniques philosophers know but we typically havent been taught.