=Different states of mind can mean the same.= The function by which we mark off, discriminate, draw a line round, and identify a numerically distinct subject of discourse is called _conception_. It is plain that whenever one and the same mental state thinks of many things, it must be the vehicle of many conceptions. If it has such a multiple conceptual function, it may be called a state of compound conception. We may conceive realities supposed to be extra-mental, as steam-engine; fictions, as mermaid; or mere _entia rationis_, like difference or nonentity. But whatever we do conceive, our conception is of that and nothing else--nothing else, that is, _instead_ of that, though it may be of much else _in addition_ to that. Each act of conception results from our attention's having singled out some one part of the mass of matter-for-thought which the world presents, and from our holding fast to it, without confusion. Confusion occurs when we do not know whether a certain object proposed to us is _the same_ with one of our meanings or not; so that the conceptual function requires, to be complete, that the thought should not only say 'I mean this,' but also say 'I don't mean that.' Each conception thus eternally remains what it is, and never can become another. The mind may change its states, and its meanings, at different times; may drop one conception and take up another: but the dropped conception itself can in no intelligible sense be said to _change into_ its successor. The paper, a moment ago white, I may now see to be scorched black. But my _conception_ 'white' does not change into my _conception_ 'black.' On the contrary, it stays alongside of the objective blackness, as a different meaning in my mind, and by so doing lets me judge the blackness as the paper's change. Unless it stayed, I should simply say 'blackness' and know no more. Thus, amid the flux of opinions and of physical things, the world of conceptions, or things intended to be thought about, stands stiff and immutable, like Plato's Realm of Ideas. Some conceptions are of things, some of events, some of qualities. Any fact, be it thing, event, or quality, may be conceived sufficiently for purposes of identification, if only it be singled out and marked so as to separate it from other things. Simply calling it 'this' or 'that' will suffice. To speak in technical language, a subject may be conceived by its _denotation_, with no _connotation_, or a very minimum of connotation, attached. The essential point is that it should be re-identified by us as that which the talk is about; and no full representation of it is necessary for this, even when it is a fully representable thing.