The Puzzle
Consider the following two sentences:
(1) Hesperus is Hesperus.
(2) Hesperus is Phosphorus.
We can begin by noting that each of these sentences is true, and that 'Hesperus' refers to the same object as 'Phosphorus' (the planet Venus). Nonetheless, (1) and (2) seem to differ in what Frege called cognitive value. One way of analyzing this notion is to say that a person could rationally believe (1) while denying (2). The problem, however, is that proper names are often taken to have no meaning beyond their reference (a view often associated with John Stuart Mill). But this seems to imply that if a person knows the meanings of the words in (1) and (2), he cannot rationally believe one and deny the other: (1) and (2) are synonymous.
Read more about this topic: Frege's Puzzle
Famous quotes containing the word puzzle:
“Waiting for the race to become official, he began to feel as if he had as much effect on the final outcome of the operation as a single piece of a jumbo jigsaw puzzle has to its predetermined final design. Only the addition of the missing fragments of the puzzle would reveal if the picture was as he guessed it would be.”
—Stanley Kubrick (b. 1928)
“—My good friend, quoth I—as sure as I am I—and you are you
—And who are you? said he.—Don’t puzzle me; said I.”
—Laurence Sterne (1713–1768)