The full statement of 'All Greeks are mortal' is 'For all possible values of x, if x is Greek, x is mortal'. We have here, instead of a subject-predicate proposition, a connection of two propositional functions, each of which becomes a subject-predicate proposition when a value is assigned to the variable x. The statement, 'All Greeks are mortal', says nothing about Greeks in particular, but is a statement about everything in the universe.
Source: My Philosophical Development, chap. 6,1959
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