The usual treatment of the meaning of predicates differs slightly from the manner I have described here. Usually, the intension of a predicate is taken to be a function from possible worlds to sets of individuals (or sets of ordered pairs of individuals for binary relations, ordered triples for three place relations, and so on). Strictly speaking, these functions are not propositional functions because they do not take propositions as values. But for each such function, we can construct an ‘equivalent’ propositional functions by using a process called ‘Currying’ after the logician Haskell Curry. Let's start with a function f from worlds to sets of individuals. Then we can construct the corresponding propositional function g as follows. For each world w and individual i, we construct g so that