What is Philosophy?
Possibly the most common answer heard to this question comes from the simple dissection of the word "philosophy". In Greek, phileo means "to love" and sophia means "wisdom" so the literal meaning of philosophy is "the love of wisdom;"" a broad subject area to be sure.
While this definition is certainly not inaccurate, it does need some refining. To the ancient Greeks, such a broad meaning was perfectly apt since philosophy encompassed all of what we would today classify as science. Post-scientific revolution, when science and technology really came into its own based on the scientific method, philosophy has come under attack, to the point where physicists as eminent as Lawrence Krauss and Stephen Hawking can feel justified in asserting that philosophy is dead, or at best, obsolete.
If we think of philosophy as a bunch of people sitting around posing questions to themselves ("What is this cup made of?" or "What is a thought?") and suggesting answers ("Atoms" or "The firing of neurons"), then yes, philosophy is dead and what's more, we ought to have killed it. But this is a straw man. While these kinds of questions used to come under the auspices of philosophy, they are now scientific ones and can be best pursued through the scientific method. But only (some) scientists think philosophy is like this.
I think of it like this; there are two broad realms, the world and the human. Both of these are best investigated through science, the 'hard' sciences for the former (physics, chemistry, etc.) and 'soft' for the latter (psychology and sociology), but science cannot address the unique human questions about these subjects (that science elucidates so well) that arise from our unique human perspective.
Science can tell us that our thoughts come from the interactions of neurons in a physical organ but what does this mean for us? Does this reduce us to nothing more than sophisticated biological robots? (If yes, why should we treat each other any differently than we treat any of the other machines that surround us?) Does our experience of these thoughts as coming from a localised "me" therefore mean nothing? How does this affect our relationships with others? How about with ourselves? There are no experiments we can conduct to answer these kinds of questions because they are qualitative, not quantitative. And what's more telling in this context is that these questions would be meaningless in a human-less universe (and of course, by 'human' I mean any limited but self-aware consciousness structured in such a way that it shares certain features of human consciousness). In other words, philosophy addresses 'human' questions.
This reveals something important about philosophy. If there were no humans there could be no philosophy either… but there could still be science (in theory at least, setting aside the question of who would be doing the science). Even when philosophy is at its most abstract, in say, analytic philosophy (logic, language, etc.) or metaphysics (God, being, etc.), the questions invariably turn on specifically human concerns and/or features. In contrast, science explicitly aims to exclude the human from its considerations. Any version of philosophy that attempts to compete with science in this respect will ultimately end up impoverished and unable to avoid making a mockery of a subject that has an extremely distinguished pedigree and deserves a central role in our lives, not necessarily because it gives definitive answers, but because it makes us think about the questions.
If we were nothing more than the organisms science reduces us to, questions about life would be easy to deal with… because there wouldn’t be any. To achieve Y, do A, B, and D. Simple. But this will never satisfy us as humans. We have more concerns than this. Does my doing A affect anyone else?, should that matter to me?, do I even want Y?, are there any other options?, why or why not?… and the list goes on. Anytime you find yourself asking questions that can’t be quantified or answered definitively after performing a well-designed experiment, you are doing philosophy. And I’m willing to bet that they will also be the questions that matter most to you.