I’m going to rely on Plato’s Apology, which can be read here, to define philosophy. There were philosophers before Plato and Socrates, but in this work Socrates is a paradigmatic example of a philosopher, and he provides us with a helpful example. In this reading we find Socrates on trial for i) atheism and ii) corrupting the youth of Athens. The book is essentially the transcript of how Socrates defends himself against these accusations, and then what he believes his sentence should be, and finally how he respond to the sentence handed down. I think we can derive 5 features of philosophy from this text.
We can glean from this reading that philosophy is an area of study. It is the area that studies the most basic questions that can be asked. It asks the questions that other disciplines assume. Physics assumes the material world, psychology makes assumptions about the mind, brain, and human nature, literature makes assumptions about history, texts, and meaning, etc. What we find Socrates doing is going to different groups and asking them basic questions. Some of these questions are about the assumptions behind what the group studies or does, others are simply the most basic questions that can be asked by anyone independent of what they study or do.
We also see in Socrates an example of the attitude behind philosophy. The term “philosophy” means “the love of wisdom.” A disciple of Socrates went to the Oracle at Delphi and asked “who is the most wise?” The Oracle responded “Socrates.” This created a problem for Socrates in that he personally didn’t believe he was the most wise and thought he could find many examples of persons wiser than he, but he also didn't want to doubt the Oracle. Consequently he set out to find such examples. He went to three groups, the politicians, the artists, and the craftsmen. In each case what he found is that although the persons he talked to thought they were wise, upon examination through asking questions it was revealed that they were not wise. They thought they knew, but did not know. Therefore, Socrates concluded that only real difference between himself and these persons was that where they thought they know but do not, he knows that he does not know. And this is what the Oracle must have meant: “he is the most wise who, like Socrates, knows that he does not know.” Without this attitude of the love of wisdom it will not be possible to study philosophy. If one does not love wisdom one will not seek it, and will instead be content with the appearance, but not the reality, of wisdom.
Socrates also shows us that philosophy is a method. Other philosophers, for instance Aristotle, attempted to make this method more explicit. However, in this reading we see Socrates using reason to test beliefs for meaning. The critical use of reason is the use of the laws of thought (identity (a is a), non-contradiction (not both a and non-a), and excluded middle (either a or non-a) to test beliefs for meaning. Socrates asks Melitus "what does it mean to corrupt the youth?" and "what does it mean to be an atheist?" It is quickly seen through this dialogue process that Melitus has contradictory answers. Any belief that violates a law of thought has no meaning, and where there is meaning reason is being used. There are numerous examples of this method in the dialogue process used by Socrates.
Socrates gives us the dictum “the unexamined life is not worth living.” This is the application of philosophy. Indeed, he states at the end of the Apology that he’d rather accept the death sentence than continue to live in Athens and not be able to live the examined life. He points out that in dying he simply goes to the next life where he can continue to live the examined life and ask those there if they are wise or if they only think they are wise, whereas to be deprived of this in Athens is no life at all. This application begins with self-examination. Although Socrates is asking other people questions, he is doing this in the spirit of self-examination, to see if he knows or only thinks he knows. Self-examination is in contrast to self-deception (where we think we know but do not) and self-justification (when we defend our ignorance and refuse to live the examined life).
Finally, philosophy is a system or worldview. Although in the Apology Socrates does not give us his entire worldview, this work is part of a trilogy depicting the trial and death of Socrates (the other parts being the Crito and the Phaedo), where Socrates does give us his worldview. In doing this he is giving us an example of philosophy as a system. This does not mean that the Socratic worldview fleshed out in the Phaedo is true. Indeed, it must be subjected to the method of philosophy just as any other worldview. But it does mean that he provides us an example of this feature of philosophy. Schools of philosophy, including the Socratic and Platonic, are developed and take their place in the history of philosophy as they go through the kind of critical examination that Socrates exemplifies in the Apology. Civilizations, as living expressions of worldviews, go through this same process and grow, are challenged, and in some cases die, when the answers they give to basic questions are critically examined.
Taken together, these 5 features of philosophy give us a definition of philosophy and show how it fits into the academy. Philosophy is unique among all disciplines at the university in that it alone asks and seeks to answer the most basic questions that can be asked. All other disciplines share the feature of making assumptions about these questions and building from there. In this sense philosophy provides the foundation for all other disciplines at the university.