The evidence. At 1051b1 the main witnesses present a variety of readings: Ab and (probably) ps.-Alexander (in Metaph. 598, 1–2) have ‘κυριώταταὂν’; the first hand of E has ‘κυριώτατον εἰ’; J and the second hand of E have ‘κυριώταταεἰ’; William of Moerbeke's translation presupposes ‘κυριώτατα ἢ’.

Brandis, Bekker, Weise, Schwegler, Bonitz, Dübner, Christ, and Jaeger print ‘κυριώτατα ὂν’. Ross (followed by Tredennick and various commentators) excises ‘κυριώτατα ὂν’ (he also contemplates the possibility of transposing it after ‘τὸ μὲν’ at 1051a34). Jaeger suspects a lacuna between ‘κυριώτατα ὂν’ and ἀληθὲς ἢ ψεῦδος’: he suggests ‘κυριώτατα ὂν <ἡ οὐσία, λείπεται δὲ ἐπισκοπεῖν τὸ ὂν> ἀληθὲς ἢ ψεῦδος’.

An inconsistency? Many editors and commentators find the reading ‘κυριώτατα ὂν’ of Ab at 1051b1 hard to accept because in Metaphysics E 4 (= T7), at 1027b31, Aristotle says that what ‘is’ in the sense of being true ‘is a different thing that “is” from the things that “are” in the strict sense [κυρίως]’: were the reading ‘κυριώτατα ὂν’ genuine, in Metaphysics Θ 10 Aristotle would be committing himself to the incompatible claim that what ‘is’ in the sense of being true is what ‘is’ in the strictest sense. The fact that E 4, at 1027b28–9, contains a forward reference to Θ 10 makes it particularly implausible to assume that Aristotle should entertain such incompatible views about what ‘is’ in the sense of being true.