The branches of philosophy are the standard divisions of philosophical inquiry. Most maps name five core areas: metaphysics, epistemology, ethics, logic, and aesthetics, with political philosophy and the various philosophies of (mind, language, science) treated as further subfields.
Philosophy is large enough that no single entry can survey it, so the discipline is usually presented as a set of branches, each defined by the kind of question it asks. The divisions are not watertight, and the labels have shifted across history, but a working map helps a reader see where any given problem sits. A question about whether the future is fixed belongs to metaphysics; a question about whether we can ever know it belongs to epistemology; a question about what we owe one another belongs to ethics. The map below follows the grouping that most reference works adopt, then notes where the lines blur.[1]
A useful first cut comes from antiquity. Aristotle divided knowledge into the theoretical, the practical, and the productive, a scheme that still echoes in the modern split between inquiry aimed at truth, inquiry aimed at action, and inquiry aimed at making. Later writers reorganized the parts, but the impulse to chart the field by its aims has stayed constant. NoteThe term axiology, the study of value, is sometimes used to group ethics and aesthetics under one heading.
Metaphysics
Metaphysics studies the nature of reality at its most general: what exists, what kinds of things there are, and how they relate. Its core part, ontology, asks which entities are basic and which are derived. Other questions concern existence, time, space, causality, identity over change, and the relation between mind and matter. The mind-body problem, the debate over free will and determinism, and the status of properties and universals all fall here. Metaphysics is often described as inquiry into what lies beyond the reach of the particular sciences, though many of its questions now run alongside physics and cognitive science rather than apart from them.
Epistemology
Epistemology is the theory of knowledge. It asks what knowledge is, how beliefs are justified, what truth amounts to, and how far reasonable doubt can be pushed. The classical analysis treated knowledge as justified true belief, a definition that held until a short paper showed that the three conditions can be met by accident without yielding knowledge.[2] Long-running disputes set rationalism, which grants reason an independent source of knowledge, against empiricism, which traces knowledge to experience, and weigh the force of skeptical arguments that question whether justification ever succeeds. The distinction between a priori and a posteriori knowledge is a standard tool of the field.
Ethics and axiology
Ethics examines conduct and value: how one ought to live, what makes actions right or wrong, and what is worth pursuing. It is conventionally divided into three levels. Normative ethics builds and defends general theories, the most discussed being consequentialism, which judges acts by their outcomes; deontology, which judges them by duties and rules; and virtue ethics, which centers on character. Meta-ethics steps back to ask what moral claims mean and whether they can be true. Applied ethics takes the theories to concrete cases. Thought experiments such as the trolley problem are used to test how the theories handle hard choices.
Aesthetics
Aesthetics is the study of beauty, art, and taste, and of responses such as the sublime. It asks what makes something a work of art, whether aesthetic judgments can be correct, and how value in art relates to moral and practical value. Because it concerns value rather than fact, aesthetics is often paired with ethics under the heading of axiology.
Logic
Logic is the study of correct reasoning. It supplies the standards by which a good argument is told from a bad one, distinguishing a valid argument, whose conclusion follows from its premises, from a sound one, whose premises are also true. The field separates deductive inference, where the conclusion is guaranteed, from inductive inference, where it is only supported. Logic serves every other branch, since each advances by argument, and it shades into the philosophy of language where the questions turn to meaning and reference.
The branches are not separate countries with closed borders. A claim in ethics rests on a view of knowledge, which rests in turn on a view of what there is. editorial summary
Subfields and overlaps
Beyond the core five, philosophy has grown a set of subfields named for their subject matter: philosophy of mind, of language, of science, of religion, and of art, among others. Political philosophy, concerned with justice, authority, rights, and the legitimacy of the state, is sometimes counted as a branch in its own right and sometimes as a region of ethics. These areas borrow freely from the core: philosophy of science draws on epistemology and metaphysics, while political philosophy draws on ethics and logic. The map is best read as a network rather than a tree.[3] Comparative work also sets Western divisions beside the traditions of Indian, Chinese, and other philosophies, whose organizing categories do not always match.
The applied turn
Many of the field's most active questions now arise where philosophy meets technology. The ethics of artificial intelligence draws on every branch at once: questions of moral status and machine alignment turn on ethics, questions about what a system can be said to know turn on epistemology, and questions about whether a machine could have a mind turn on metaphysics. The branches supply the vocabulary and the standards of argument; the new cases test whether the old distinctions still hold. Readers new to the field can use the map as a starting index, then follow the cross-links, since the interesting problems rarely sit inside a single branch. See also the about page for how these entries are prepared.