One of the more esoteric problems of philosophy is that no one knows what it is. I exaggerate, of course, but philosophy as an academic discipline is notoriously difficult to define. Translated from the Greek, philosophy indicates love of wisdom. In practice, however, philosophers engage in a variety of pursuits and approaches that defy summary—so much so that we might despair as to what they have in common. That said, much of what we see in philosophy’s traditions and pursuits can be summed up, a bit untidily, as follows: philosophy is a reason-based attempt to answer deep, persistent questions that have long caused puzzlement and anxiety.
Which questions? Every philosopher has a preferred list, but here are just a few. Is there a god or an afterlife? Do we possess free will? How can we know about the external world? Are moral rules objectively binding on us? What is a good life for a human being? What is the nature of a just society? At a more esoteric level of discussion, what sort of evidence might be needed to answer questions such as these? Can we even explain what we’re talking about when we employ terminology such as free will? To deal with all this, philosophy extends into examining the foundations, and perhaps the limits, of inquiry itself. Thus, its subdisciplines include logic and epistemology (or theory of knowledge).