Philosophy is the quest for comprehensive human understanding. The objective of philosophy is to consider the rational justification of logical inferences, human values, criteria for establishing claims of knowledge and certainty, and interpretations of the nature of reality. As a discipline, philosophy is unique from other fields because its subject matter covers every dimension of human existence and its techniques can be applied to any field of study. Philosophy may examine concepts and views drawn from science, art, religion, politics, or any other realm. Although the philosophical appraisal of ideas and issues may take many forms, philosophical studies often focus on the meaning of an idea and on its basis, coherence, and relations to other ideas.

The traditional subfields of philosophy are logic, ethics, metaphysics, epistemology, and the history of philosophy as described briefly below:

Logic is concerned to provide sound methods for distinguishing good and bad reasoning. It helps assess how well premises support conclusions, show what consequences may result from commitment to a certain view, and avoid adopting beliefs that lack adequate reasons.

Ethics is the study of moral concepts, such as right action, obligation, and justice, and formulates principles to guide moral decisions. Recently, ethics have become specialized into particular areas of study, such as medical ethics or business ethics.

Metaphysics seeks the criteria for determining the fundamental nature of reality and its objects.

Epistemology is concerned with the nature and scope of knowledge, particularly about what constitutes truth and whether humans can know it.

History of Philosophy studies major philosophers and entire periods of development of philosophy, such as Ancient, Medieval, and Modern. It seeks to understand great figures, their influence on others, and their importance for contemporary issues.

Many branches of philosophy have grown from the traditional core areas, as sketched below:

Philosophy of Art is the study of all aspects of art and examines questions of aesthetics, such as how artistic creations should be interpreted and evaluated, and how art is related to beauty, morality, religion, science, and other important elements of human life.

Philosophy of Language treats a broad spectrum of questions about language: the nature of its meaning, the relations between words and things, the various theories of language learning, and the distinction between literal and figurative uses of language.

Philosophy of Law explores such topics as what is law, what kinds of laws exist, and whether law should be related to morality.

Philosophy of Mind focuses the mind and mental phenomena. Besides the study of the relations of the mental to the physical, the philosophy of the mind also addresses concepts that have an essential mental element, like belief, desire, emotion, feelings, sensation, and will.

Philosophy of Religion is concerned with the concept of God, including special attributes to it like omnipotent, omniscience, and moral goodness.

Philosophy of Science is usually divided into natural sciences and social sciences, and sometimes even into particular disciplines, such as biology, psychology, and economics. Philosophy of science clarifies both the quest for scientific knowledge and the results from that quest.

Political Philosophy concerns the justification and limits of governmental control of individuals as well as clarifies basic political concepts like equality, freedom, and democracy. Often, Social Philosophy is taught in combination with political philosophy and looks at moral problems that have large-scale social dimensions.

Other subfields in philosophy that are taught are Philosophy of Logic, Philosophy of History, Philosophy of Mathematics, Philosophy of Education, Philosophy of Linguistics, Philosophy of Criticism, and Philosophy of Culture.