Essentialist theories are based on notions of necessity and essentiality. Kinds and Quasi-Kinds can be defined in terms of these notions. Aristotle's essentialism asserts that Kinds are unions of Quasi-Kinds, Kinds that can overlap are necessarily included in a common Kind, and Kinds partition into sub-Kinds. Truth-conditions for the apodeictic propositions of Aristotle's modal syllogistic are stated in terms of necessity and essentiality, but independent of theses -. While the basic insights motivating Patterson's and Nortmann's interpretations of modal syllogistic are (...) sound, nonetheless there are significant mistakes in the detail. Given -, truth-conditions for apodeictic propositions can be stated in terms of essentiality, but independently of the notion of necessity, thus confirming Johnson's interpretation. (shrink)