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:
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—Henry David Thoreau (1817–1862)
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