Philosophy — etymologically, the “love of wisdom” — is generally the study of problems concerning matters such as existence, knowledge, justification, truth, justice, right and wrong, beauty, validity, mind, and language. Philosophy is distinguished from other ways of addressing these issues by its critical, generally systematic approach and its reliance on reasoned argument, rather than experiments (Experimental philosophy being an exception).
Philosophy used to be a very comprehensive term, including what have subsequently become separate disciplines, such as physics. Today, the main fields of philosophy are logic, ethics, metaphysics, and epistemology. Still, there continues to be plenty of overlap with other disciplines; the field of semantics, for example, brings philosophy into contact with linguistics.
Since the early twentieth century, the philosophy done in universities (especially in the English-speaking parts of the world) has become much more analytic. Analytic philosophy is marked by a clear, rigorous method of inquiry that emphasizes the use of logic and more formal methods of reasoning.