There are two main reasons people study philosophy. The first is simple curiosity. This is as true for the most advanced graduate student pursuing highly specialized research as it is for the first-year undergraduate looking for something new and interesting to study that wasn't taught in High School. Broadly construed, philosophy began by attempting to answer two deceptively simple questions:

What can we know?, and
How should we live our lives?

These questions in turn gave rise to others: Can we ever have absolutely certain knowledge? What constitutes a good reason for believing something? Must we always have evidence in order to know? Are there things about the world that are in principle impossible to know? Are mind and body distinct? Are people ever really free? Is there a God? Do numbers exist? Is beauty in the eye of the beholder? Why should we obey the law? Under what conditions is it right to restrict a person's liberty? Is capital punishment immoral? Do trees have rights? How can moral disagreements be rationally settled? Which takes precedence over the other, the Right or the Good? What is truth? Is the sentence "This sentence is false" true or false?

Over the centuries, questions such as these have given rise to the main great subdisciplines within philosophy, including Epistemology (the theory of knowledge), Metaphysics (the theory of being), Logic (the theory of reason and of inference), Value Theory (including ethics, politics and aesthetics), and the History of Philosophy.

The second main reason people study philosophy is that many of the skills and abilities that are learned in philosophy are transferable, not just to other academic disciplines, but to other endeavors as well. This is partly because philosophy touches on so many other subjects, and partly because its methods are widely applicable to other areas of intellectual accomplishment. Communication skills, critical reasoning skills, and general problem-solving skills are all enhanced by work in philosophy. They are also essential to many other disciplines and projects. In addition, philosophy helps students develop sound methods of research and analysis. By its nature, Philosophy also helps students to organize and unify information that they may have learned only in a piecemeal way in other courses.