[1] Frege's distinction between sense and reference is well-known, not to say notorious, and both the distinction itself as well as its constituents have received a fair amount of attention.¹ Especially the notion of sense. However most of the discussions have been conducted on a logico-semantic level, with particular emphasis placed on how well or ill Frege's speculations apply to ordinary language.² The question of the metaphysical nature of Fregean senses and their place in his metaphysical system, if it has been raised at all, has usually been accorded little more than a few perfunctory comments along more or less traditional interpretational lines. And that is unfortunate: Not only because this approach fails to give a complete picture of Frege's metaphysics, but also because this deprives the reader of a view of one of the most peculiar and at the same time one of the most seminal metaphysics of meaning of modern times. Without it, the theories of the Tractatus would scarcely have been possible; and if Frege had not made his peculiar pronouncements, it is doubtful that the controversy over the nature of meaning which characterized such a great deal of recent Anglo-American philosophizing would ever have come about. Certainly, it would not have assumed the nature it did.