The Distinction between Concepts and Ideas

Propositions have an inner complexity. If a proposition is believed (restricting ourselves to beliefs for the present) then the belief-state will have to have an inner complexity which mirrors the complexity of the proposition.

How is this complexity of the belief-state to be conceived? The analogy of a map seems useful. Suppose that what is believed is that Perth is to the west of Sydney. In a map, this putative state of affairs would be represented by two marks on the map, one labelled ‘Perth’, the other ‘Sydney’, the former being to the left of the latter. These marks, thus labelled and thus related, represent a state of affairs. Let us think of the belief-state as a sort of map. It will contain elements, like the map-marks labelled ‘Perth’ and ‘Sydney’, which have a certain interpretation. These elements will be related in certain ways, just as the map-marks are related in a certain way in the map, and the relations of the elements will also have a certain interpretation. Given this interpretation of the elements and the relations, the elements-in-relation to be found in a particular belief-state determine what it is that is believed. (The elements may themselves be complex, involving further elements-inrelation, but, since the human mind is finite, we must in the end come to elements whose parts do not represent.) In general, at least, the relations in the belief-state will represent relations in the world, and the elements in the belief-state the terms of relations in the world.