the truth of our ideas cannot consist in the fact {22} that they are copies of realities, for clearly they are not copies in any possible meaning of the term. Take, for example, this very illustration of seeing a landscape: what we see is not a picture or copy of the landscape, but the real landscape itself. We feel quite sure of this, and with regard to the other sensations, those that come to us by hearing, taste, smell, touch, it would seem highly absurd to suppose that the ideas these sensations produce in us are copies of real things. The pain of burning is not a copy of real fire, and the truth of the judgment, Fire burns, does not consist in the fact that the ideas denoted by the words "fire," "burns," faithfully copy certain real things which are not ideas. And the whole notion is seen to be absurd if we consider that, were it a fact that real things produce copies of themselves in our mind, we could never know it was so--all that we should have any knowledge of would be the copies, and whether these were like or unlike the reality, or indeed whether there was any reality for them to be like would, in the nature of the case, be unknowable, and we could never ask the question. If, then, our ideas are not copies of things, and if there are things as well as ideas about things, it is quite clear that the ideas must correspond to the things in some way that does not make them copies of the things. The most familiar instance of correspondence is the symbolism we use in mathematics. Are our ideas of this nature? And is their truth their correspondence? Is a perfectly true idea one in which there exists a point to point correspondence to the reality it represents? At once there will occur to the mind a great number of instances where this seems to be the case. A map of England is not a copy of England such as, for example, a photograph might be if we were to imagine it taken {23} from the moon. The correctness or the truth of a map consists in the correspondence between the reality and the diagram, which is an arbitrary sign of it. Throughout the whole of our ordinary life we find that we make use of symbols and signs that are not themselves either parts of or copies of the things for which they stand. Language itself is of this nature, and there may be symbols of symbols of symbols of real things. Written language is the arbitrary visual sign of spoken language, and spoken language is the arbitrary sign, it may be, of an experienced thing or of an abstract idea. Is, then, this property of our ideas which we call truth the correspondence of ideas with their objects, and is falsity the absence of this correspondence? It cannot be so. To imagine that ideas can correspond with realities is to forget that ideas simply are the knowledge of realities; it is to slip into the notion that we know two kinds of different things, first realities and secondly ideas, and that we can compare together these two sorts of things.