¹ ‘The orthocomplement, U ^⊥, of a set of possibilities U comprises precisely those possibilities that are incompatible with every member of U. Thus x ∈ U ^⊥ if and only if x⊥y for all y ∈ U.’ (167)

² Hale, ‘Absolute Necessities’ Nous Supplement: Philosophical Perspectives, 10, Metaphysics 30 (1996)Google Scholar: page 100. See also Fine, ‘Essence and Modality’, Philosophical Perspectives 8: Logic and Language (1994): 1–16 Google Scholar; Fine, Modality and Tense: Philosophical Papers (London: Clarendon Press, 2005); Hale, Necessary Beings: An Essay on Ontology, Modality, & the Relations Between Them (Oxford University Press, 2013); Shalkowski, ‘Essentialism and Absolute Necessity’, Acta Analytica 12 (1997): 41–56 Google Scholar; Shalkowski, ‘Logic and Absolute Necessity’, The Journal of Philosophy CI:55–82 (2004)Google Scholar

³ Hale, ‘Absolute Necessities’, 95.

⁴ Thanks to Bob Hale, Rosanna Keefe, and Mark Textor, for helpful comments on earlier versions of this review.