Good, let's start with the tough questions. Philosophers are characterised chiefly by their ability to argue about anything, and they even argue about what Philosophy is. So there will be plenty of philosophers who would disagree with at least some of what is said here.
Philosophers see problems where other people don't. It's quite common, for example, for one person to ask another how they know something, e.g.
My Dad's home.
Oh yeah? How do you know?
His keys are on the table.
Now for most people, such exchanges end there. Some of us, however, are occasionally prompted to consider the reasoning being engaged in here: is the presence of the keys really conclusive evidence of Dad's presence? It's easy to think up scenarios in which the keys are present but he is absent (he forgot them, he came home and then popped out again, he's been kidnapped by aliens, your memories of having a father are false, etc.).
This turns philosophical when it becomes an investigation not of whether Dad is home or not, but an investigation of the relationship between experience, evidence, belief and knowledge. For instance, if you think that seeing the keys is enough to give you knowledge of Dad's presence, the cases in which the keys are there but he isn't will cause problems: you'll 'know' something that isn't true. But if you react to this by deciding that you only know something if you can be absolutely certain of it, you may end up worrying that you don't know anything. If you try hard enough, just about any evidence can be doubted, even if it's right in front of you. You could be dreaming, or in the Matrix, and so on.
This is the kind of thing that kicks off Descartes' philosophy. He tries to work out what he can be certain of, in order to defeat scepticism. In the end he thinks that he can be certain of quite a lot: his own existence, the world's existence, and even God's. Whether he was right is something you'll have to decide for yourself if you study Philosophy.
That's one of the good things about studying Philosophy, actually. You meet the great minds of history on equal terms. You don't just learn what they thought, you engage with them critically. Sometimes you catch someone like Aristotle using a flawed argument, and you can say what mistake he's making.
You: one. Great minds of history: nil.
Soon you'll doing the same with philosophers working today, evaluating their claims and arguments and finding reasons to disagree with them. A large part of doing Philosophy is learning how to do this: how to understand what others think and write, and be able to examine their arguments for weak spots and errors. This is an ability which carries over into your whole life. You'll win more arguments in the pub, and you'll hear politician's speeches in a whole new way.
Imaginative flexibility and inventiveness
The ability to criticise other people's views and arguments effectively isn't the whole story, however. Good philosophy requires clarity and rigour of thought, but also it calls for imaginative flexibility and inventiveness. It's all very well being able to argue convincingly that the standard arguments for the existence of God don't work, but can you do any better? Or can you think of principled reasons why the existence of God just can't be proved? Once you start being able to formulate and justify your own views, you're really starting to think like a philosopher.
Philosophy is the ideal discipline for people who find that they are bothered by questions that their friends can cheerfully ignore, and for people who don't want to settle for conventional answers and received wisdom, but want to arrive at answers that stand up to the most searching examination.
Another way to answer the question, 'what is philosophy?' is of course simply to list the kinds of topic and issue that typically come under the heading of 'philosophy'. So let's do it that way as well - or at least make a start, because it's a very long list!
Philosophy gets divided up into sub-fields, all of which relate to and interact with each other. Some of the central ones are:
- Metaphysics - dealing with appearance and reality, with substance, causation, identity, the freedom of the will, and so on
- Epistemology - dealing with the foundations, scope and limits of knowledge
- Ethics - dealing with the nature of morality, with whether there is an absolute standard of morality, with the basis of justice
- Philosophy of Mind - dealing with the nature of the mind, its relationship with the body, the character of thought and feeling, the nature of conscious experience
But there are lots of others too: political philosophy, aesthetics, philosophy of language, philosophical logic, philosophy of science - and so on, and on!