Aristotle, who was himself a very great philosopher, said that philosophy begins in wonder. What happens next, in response to this sense of wonder, depends on the person doing philosophy and on the particular things he or she is considering. It usually happens that one philosophical question leads to another, as you'll soon see for yourself. As a result, it's somewhat artificial to make hard and fast divisions among the topics philosophy addresses. Still, it's helpful to have labels for clusters of problems, issues, and approaches within philosophy as a whole.
No area is more central to philosophy than ethics. A concern with ethics arises naturally from the moral problems we face in everyday life. These include: "When, if ever, is it all right to break my promises?" "Is it bad to kill animals?" "Should abortions be allowed?" "Why should I be moral, if I can get away with doing something immoral?" The philosophical study of ethics addresses such questions directly. It also places them in a wider context, by examining questions like what, in general, makes an action good or bad, or what do we mean when we say that someone has a right or an obligation to do something. Ethical issues are closely connected to those that arise in social and political philosophy. Here, philosophers consider various conceptions of the state and what would make it legitimate for the state to exert power over its citizens; similarly, we ask about the proper balance between the demand of individual freedom, on the one hand, and the welfare of society as a whole.
Intellectual activity—whether it's philosophy, history, biology, or anthropology—is in large part the pursuit of knowledge. Philosophy is distinctive, however, in that one of its subjects is the nature of knowledge itself. Knowing is apparently different from lucky guessing or from superstition, but how? Epistemology is the branch of philosophy that tries to understand what is special about knowledge. Epistemologists also ask how we can be confident that we have much knowledge; how can we be sure that we aren't thoroughly mistaken about things? Scientific knowledge raises special issues of its own, so there is a field called the philosophy of science. How can we distinguish between scientific and pseudo-science like astrology? Certainly, science is useful, but does it give us a true picture of reality? Even when it talks about things we can't observe or even imagine, like electrons or black holes?
Some questions about reality seem to lie beyond the scope of any natural or social science. The broadest and most fundamental issues of this sort are taken up in metaphysics. For example, we might assume that material objects like tables are real, but what about numbers or ideas? Metaphysics also tries to understand what causation is, what free will is, and how we can be free if our actions are ultimately caused by circumstances over which we have no control. Metaphysics is a close cousin to the philosophy of mind. Philosophers of mind consider what consciousness is, and whether a machine could think. And they try to understand the relation between mind and body (that is, whether we ourselves are anything more than complex biological "machines").
Now, it may well be that animals other than ourselves are conscious and capable of thought, but only humans have the ability to express their thoughts in language. In the philosophy of language, we try to understand what makes the words we use meaningful, rather than mere noises or marks on a page. We also inquire about how it is possible to learn a language in the first place or to share a language with others.
This list could go on and on. But we'll conclude by mentioning two further areas of philosophy that, in some sense, embrace all the ones we've previously mentioned. The first is logic, which is a rigorous examination of reasoning and inference. Logic provides the standard by which we can assess the worth of arguments in philosophy (and elsewhere), so of course the study of logic is extremely useful. But it is also a fascinating, even surprising, subject in its own right.
Finally, philosophy has been going on for a very long time. Current philosophical thought is very much enriched and shaped by the writings of great philosophers of the past. In the history of philosophy, those writings are studied carefully, and this study develops your ability to read and analyze materials of great subtlety and depth. These skills are of value in any context, but here, in particular, they will allow you to encounter some of the most compelling and profound creations of the human mind.