It is needless in this discussion to dwell at length upon the general principle of recent "functional" psychology, that practical ends are the controlling factors in the acquisition of our knowledge of objective things. We shall take for granted the truth of the general proposition that cognition, in whatever sphere of science or of practical life, is essentially teleological in the sense of being incidental always, more or less directly, to the attainment of ends. Cognition, as the apperceptive or attentive process, is essentially the process of scrutinizing a situation (whether theoretical or practical) with a view to determining the availability for one's intended purpose of such objects and conditions as the situation may present. The objects and conditions thus determined will be made use of or ignored, counted upon as advantageous or guarded against as unfavorable--in a word, responded to--in ways suggested by their character as ascertained through reference to the interest in question. In this sense, then, objective things as known by individual persons are essentially complex stimuli whose proper function and reason for being it is to elicit useful responses in the way of conduct--responses conducive to the realization of ends.
From this point of view, then, the difference between one person's knowledge of a particular object and another's signifies (1) a difference between these persons' original purposes in setting out to gain knowledge of the object, and (2) consequently a difference between their present ways of acting with reference to the object. The bare object as socially current is, at best, for each individual simply a ground upon which subsequent construction may be made; and the subsequent construction which each individual is prompted by his circumstances and is able to work out in judgment first makes the object, for this individual, real and for his purposes complete.
Now, it is our primary intention to show that objects are, in cases of a certain important class, not yet ready to serve the person who knows them in their proper character of stimuli, when they have been, even exhaustively, defined in merely physical terms. It is very often not enough that the dimensions of an object and its physical properties, even the more recondite ones as well as those more commonly understood--it is often not enough for the purposes of an agent that these characters should make up the whole sum of his knowledge of the object in question. A measure of knowledge in terms of physical categories is often only a beginning--the result of a preliminary stage of the entire process of teleological determination, which must be carried through before the object of attention can be satisfactorily known. In the present study of the logic of valuation we shall be occupied exclusively with the discussion of cases of this kind. In our judgments of sense-perception and physical science we have presented to us material objects in their physical aspect. When these latter are inadequate to suggest or warrant overt conduct, our knowledge of them must be supplemented and reconstructed in ways presently to be specified. It is in the outcome of judgment-processes in which this work of supplementing and reconstructing is carried through that the consciousness of value, in the proper sense, arises, and these processes, then, are those which we shall here consider under the name of "processes of valuation." They will therefore best be approached through specification of the ways in which our physical judgments may be inadequate.