Philosophy can be divided into a number of areas, or subfields, though these areas overlap. These areas cluster together in fairly standard ways, though overlap between areas, even areas in different clusters, is not uncommon, and there can be slight variations in the clusters themselves.
History of Philosophy
The history of philosophy studies both major philosophers, such as Plato, Aristotle, Aquinas, Descartes, Hume, Kant, Hegel, and Nietzsche, as well as entire periods in the development of philosophy. The history of philosophy is normally divided into the ancient, medieval, modern, nineteenth-century, and twentieth-century periods. It seeks to understand great figures, their influence on others, and their importance for contemporary issues. It sometimes separately studies major philosophical movements within a single nation, such as American Pragmatism, British Empiricism, and German Idealism. The history of philosophy not only provides insight into the other subfields of philosophy; it also reveals many of the foundations of Western Civilization.
The term “continental philosophy” commonly refers to 19th-century, 20th-century, and contemporary German and French philosophy. It includes areas such as phenomenology, existentialism, critical theory, structuralism, post-structuralism, hermeneutics, and deconstruction. Principal figures include Hegel, Marx, Kierkegaard, Nietzsche, Husserl, Heidegger, Adorno, Sartre, Foucault, Derrida, Deleuze, Nancy, and Badiou.
Metaphysics and Epistemology
Traditional metaphysics addresses the question “What is there, and what is it like?" Traditional epistemology addresses the question "What is knowledge, do we have any, and if so how do we come by it?" In addition to these areas, this cluster contains the areas of philosophy of mind, philosophy of language, philosophy of mathematics, philosophy of science, philosophy of religion, and formal epistemology. Some of these areas have subareas of their own. For example, philosophy of mind includes the subareas philosophy of perception and philosophy of the emotions, and philosophy of science includes the subareas philosophy of physics, philosophy of social science, and philosophies of special sciences (e.g., psychology and economics).
Logic is primarily the study of consequence relations (the sort of relation that holds between the premises and conclusion of a “good” argument) and related notions. Among the subareas of logic are classical first-order and higher-order logics, non-classical logics (e.g., modal, intuitionistic, relevance, and many-valued logics), mathematical logic (set theory, computability theory, model theory, and proof theory), and history and philosophy of logic.
Value theory comprises the areas of ethics, social and political philosophy, and aesthetics. Ethics itself includes the subareas of normative ethics and metaethics. Normative ethics addresses questions about right conduct ("What should we do?" "Which actions are morally permissible or impermissible?"), while metaethics concerns the metaphysical and epistemological commitments of normative ethical theories, or the components of normative ethical theories (e.g., moral discourse).