German philosopher, mathematician, and logician Gottlob Frege (1848–1925) drew a distinction between two fundamentally distinct categories: objects and concepts. An object (in German, ‘gegenstand’) is the kind of thing that can be designated by a proper name like ‘Sarah’. A concept (‘begriff’) is the kind of thing that predicates like ‘…is worried’ refer to. Things which fall into one category do not fall into the other so that the distinction is mutually exclusive.
However, the distinction is not unproblematic since Frege seems to have denied himself the very means to explain it. On the face of it, it seems that Frege should want to say, for example, that ‘the concept horse is not an object’; but in so doing, he uses an expression – ‘the concept horse’ – which functions as a proper name. And since it is objects alone that may be referred to by name, he is, by his own lights, signifying an object, not a concept. This leads Frege to make the somewhat paradoxical claim that ‘the concept horse is not a concept.’ | |||