 It is intensional in that it obeys neither Leibniz’ law of substitution of co-extensional terms nor existential generalization, thereby seemingly bringing logic closer to natural language. To achieve this, Montague generalized Kripke’s (1963) groundbreaking semantic techniques from first-order modal logic to higher-order type logic. However, the same interpretive effect could have been achieved by using a two-sorted, extensional type logic (Gallin 1975; Zimmermann 1989; 2021), which many semanticsists prefer today.