The initial dilemma. I.1. The gradual rise of the Metaphysics. I.2. A bold contribution from textual history. I.3. A new perspective on late ancient commentaries. I.4. First philosophy or Metaphysics? I.5. Can tradition be ignored? II. ‘Being’ and οὐσία at the core of Aristotle’s theoretical research. II.1. Ontology as a science of ‘being’ in Aristotle: “What is X?” in the foreground. II.2. The first caveat: the copula function of Aristotle’s ‘being’. II.3. The definite article τό as quotation marks before the flexed forms of ‘be’: τὸ ὄν, τὸ εἶναι, τὸ ἔστιν. II.4. Further explanations about Aristotle’s ‘being’. III. Οὐσία, the core of Aristotle’s theoretical philosophy. III.1. οὐσία and the criterion of pre‑eminence as Plato’s legacy. III.2. The dialectical roots of ontology. III.3. οὐσία from Zeta to Lambda. III.4. οὐσία as essence and οὐσία as substance. III.5. οὐσία as a syntactical core; the word’s etymology. III.6. οὐσία as the first sense of being in Aristotle’s first philosophy. III.7. Ontology as science, science of the science. IV. Historicizing: the semantic gap. IV.1. Editorial tradition: ontology and οὐσία as a fil rouge in the order of Metaphysics books. IV.2. οὐσία in the first century B.C. IV.3. οὐσία by Alexander of Aphrodisias. IV.4. Metaphysics and its purpose: the role of the Lambda book. IV.5. Being and οὐσία: a relationship lost over time. IV.6. The Aristotelian tradition as a way to cooperation.

History of Philosophy | Philosophy and Religion