 Montague defined the denotation of a sentence as a function from possible worlds and moments of time to truth values. Such a function is called an ‘intension’. As he said (Montague 1970a, 220), this made it possible to deal with the semantics of common phenomena such as modifiers, e.g. in Necessarily the father of Cain is Adam. Its denotation cannot be obtained from the truth value of The father of Cain is Adam: one needs to know the truth value for other possible worlds and moments of time. The intensional approach also made it possible to deal with several classical puzzles. Two examples from Montague 1973 are: The temperature is rising, which should not be analyzed as stating that some number is rising; and John wishes to catch a fish and eat it, which should not be analyzed as implying that John has a particular fish in mind.