terns of such more symbolic ideas to aid in our interpretation of what we at any time merely see, such sensible ideas as photographs suggest remain, in general, very imperfect beginnings of a scientific insight into objects.
But what, then, is the test of the truthful correspondence of an idea to its object, if object and idea can differ so widely? The only answer is in terms of Purpose. The idea is true if it possesses the sort of correspondence to its object that the idea itself wants to possess. Unless that kind of identity in inner structure between idea and object can be found which the specific purpose embodied in a given idea demands, the idea is false. On the other hand, if this particular sort of identity is to be found, the idea is just in so far true. The identity that suffices to establish a sufficient correspondence must, then, be, like the identity found in two correspondent curves (as, for instance, in a given curve and in its projection), or like the identity discoverable when you compare the map with the region to which the map corresponds, — it must be, I say, an identity serving some conscious end, fulfilling an intent, possessing a value for your will. Such identity is, in the more abstract sciences, often confined to an agreement in certain very general relationships. It is, then, usually the sort of identity that the scholastics often called analogy, i.e. equivalence merely as to the common possession of certain relationships which permit the idea, for a specific purpose, as in a computation, a calculus, or in any system of ideal constructive processes, to act as a substitute, to take the place of its object. But the identity desired may, indeed, also be of a more sensuous type. If so, then, indeed, the idea must sensuously
