The Metaphysics is the foundational text of Western metaphysics in the technical sense: Aristotle's systematic inquiry into being as being, substance, causation, and the first principles of reality.
metaphysics
Aristotle's foundational treatise on being qua being, substance, causation, potentiality and actuality, and the unmoved mover — the work that gave Western metaphysics its name and most of its categories.
Composed across Aristotle's mature period; the surviving text is a compilation of materials from different periods edited by Andronicus of Rhodes c. 60 BCE.
Introduction
The Metaphysics is Aristotle's foundational treatise on being qua being, substance, causation, potentiality and actuality, and the first principles of reality. The work gave the entire Western philosophical subdiscipline of metaphysics its name — not because Aristotle called it that (he did not), but because the editor Andronicus of Rhodes placed it after the Physics (meta ta physika) in his first-century BCE arrangement of the corpus. The accidental title has organized the field ever since.
The Metaphysics is the source of most of the basic categories of Western philosophical thought about reality: substance, essence, accident, form and matter, potentiality and actuality, the four causes, the unmoved mover, the analogy of being. Two thousand years of philosophical metaphysics has been conducted substantially in terms Aristotle made available.
Form, length, date, language
The Metaphysics is a treatise in fourteen books, totaling approximately 110,000 words in Greek. The composition history is unusually complex: the surviving text is a compilation of materials Aristotle composed at different periods (some early, some late) and assembled by Andronicus of Rhodes in his definitive first-century BCE edition. The internal evidence shows multiple layers and at least one substantially independent treatise (Book Lambda, on the unmoved mover) that may have circulated separately. The original language is Attic Greek.
The books are conventionally numbered by Greek letters (Alpha through Nu); Book Alpha minor (the second book) is a brief introductory treatise of uncertain authorship that may have been added by an editor. The most-read individual books are Alpha (the historical survey of earlier philosophy), Gamma (on the law of non-contradiction and being qua being), Zeta-Eta-Theta (the central books on substance, form, and actuality), and Lambda (on the unmoved mover and divine intellect).
Why it was written
The Metaphysics opens with the famous line All human beings by nature desire to know and proceeds to inquire into the highest form of knowing — the knowledge of first principles and causes that Aristotle calls wisdom (sophia). The inquiry is conducted at the highest level of generality: not the principles of any particular science (physics, biology, ethics), but the principles of being itself, what it is to be at all.
The project is Aristotle's response to two earlier traditions. Against the Pre-Socratic cosmologists (Thales, Anaximander, Heraclitus), Aristotle argues that material principles alone cannot explain the structured intelligibility of the world; formal and final causes are also required. Against Plato, Aristotle rejects the separate existence of the Forms; forms are in substances, not in a separate realm. The positive doctrine — hylomorphism, the analysis of substance as a compound of matter and form — occupies most of the central books.
Structure and argument
Book Alpha (I). The famous opening on the desire to know; the historical survey of earlier philosophy, organized around the four causes. The book is the founding text of the history of philosophy as a self-conscious discipline.
Book Alpha minor (II). Short introductory treatise on the difficulty of inquiry and the relation between truth and being.
Book Beta (III). A systematic catalogue of the aporiai (puzzles) that metaphysics must resolve. Setting out the difficulties before proposing solutions is one of Aristotle's signature methods.
Book Gamma (IV). The science of being qua being. The famous defense of the principle of non-contradiction (1005b19–1011a2) against those who would deny it. The book establishes that metaphysics is the science of being in general, not of any particular kind of being.
Book Delta (V). A philosophical lexicon, defining approximately thirty key terms (cause, principle, substance, accident, prior, posterior, etc.). The book is essentially Aristotle's metaphysical glossary and is constantly cited as the source for technical Aristotelian vocabulary.
Book Epsilon (VI). The classification of the theoretical sciences (mathematics, physics, theology), arguing that the science of being qua being is the highest theoretical science.
Books Zeta-Eta-Theta (VII–IX). The central books on substance, form, and actuality. Zeta analyzes substance and argues that primary substance is form; Eta extends the analysis; Theta develops the doctrine of potentiality (dynamis) and actuality (energeia) as the most basic ontological distinction. These three books are the technical core of Aristotelian metaphysics.
Book Iota (X). On unity and the kinds of one.
Book Kappa (XI). A compressed summary of earlier books, possibly an alternative draft.
Book Lambda (XII). The book on the unmoved mover. Aristotle's argument that the existence of motion requires a first cause that itself does not move; the unmoved mover is thought thinking itself (noesis noeseos), an eternal divine activity. This book is the source for Western philosophical theology and was the central text in Aquinas's Five Ways and in the broader scholastic argument for the existence of God.
Books Mu-Nu (XIII–XIV). Critical engagement with Platonist and Pythagorean accounts of mathematical objects, arguing against their separate existence.
Key passages
- 980a21 — the opening: all human beings by nature desire to know.
- 983a24–993a10 — the historical survey of earlier philosophy (Book Alpha).
- 1005b19–1011a2 — the defense of the principle of non-contradiction.
- 1028a10–29 — the classification of senses of being and the priority of substance.
- 1029a1–1029b12 — the analysis of primary substance.
- 1071b3–1073a13 — the argument for the unmoved mover.
- 1072b13–30 — the description of the unmoved mover as thought thinking itself.
Reception history
The Metaphysics was the most influential single philosophical work in the medieval Islamic, Jewish, and Christian traditions. Avicenna (Ibn Sina, 980–1037) developed a sophisticated Aristotelian metaphysics, especially around the distinction between essence and existence, that shaped Islamic philosophy for centuries. Averroes (Ibn Rushd, 1126–1198) wrote the most extensive surviving Greek and Arabic commentary tradition on Aristotle, including detailed engagement with the Metaphysics. Moses Maimonides in the Guide for the Perplexed (c. 1190) integrated Aristotelian metaphysics with Jewish theology.
The Latin West recovered the Metaphysics in the twelfth and thirteenth centuries through Arabic and direct Greek translations. Aquinas's commentary, composed in the 1270s, is one of the great medieval works; the Metaphysics is the foundational text for Aquinas's own metaphysical synthesis, especially the essence-existence distinction and the Five Ways argument for God's existence.
The modern reception has been bifurcated. The early modern philosophers (Descartes, Spinoza, Leibniz) developed their own metaphysical systems in substantial dialogue with Aristotle, though typically by departing from him. The Scientific Revolution rejected Aristotelian physics but the metaphysical categories proved more durable. The empiricists and Kantians moved away from the substantialist metaphysics that the Metaphysics had grounded. The twentieth-century recovery, especially through analytic metaphysics (E.J. Lowe, Kit Fine, David Wiggins, Michael Loux) and the Heideggerian engagement with the question of being, has restored the Metaphysics to active scholarly conversation.
Contemporary engagement
The standard scholarly editions include the Loeb (Hugh Tredennick), the Oxford Classical Texts, the Hackett edition by Joe Sachs, and the multi-volume Clarendon Aristotle commentary series. Major recent monographs include Michael Frede's collected essays on the Metaphysics, Christopher Shields's Order in Multiplicity (1999), Aryeh Kosman's The Activity of Being (2013), and the relevant Clarendon volumes on individual books. Active scholarly debates concern the relation between primary and secondary substance, the interpretation of the unmoved mover (singular or plural?), the proper ordering of the books, the relation between the Metaphysics and the biological works, and the contemporary relevance of Aristotelian essentialism.
Further reading
- Aristotle — the author
- Aristotelianism — the tradition
- Form — the Platonic doctrine the Metaphysics critiques
- Aquinas — the great medieval commentator
- Logos — the rational structure the metaphysics articulates
- Plato — the teacher whose Forms are rejected
The foundational text of Western metaphysics. The source of the basic categories of philosophical thought about reality.