Imagine a situation like the following: The sole relation an organism bears to things is that of eater; the sole relation the environment bears to the organism is that of food, that is, things-to-eat. This relation, then, is exhaustive. It defines, or identifies, each term in relation to the other. But this means that there are not, as respects organism and environment, two terms at all. Eater-of-food and food-being-eaten are two names for one and the same situation. Could there be imagined a greater absurdity than to set to work to discuss the relation _of_ eater _to_ food, _of_ organism _to_ the environment, or to argue as to whether one modifies the other or not? Given the premise, the statements in such a discussion could have only a verbal difference from one another. Suppose, however, the discussion has somehow got under way. Sides have been taken; the philosophical world is divided into two great camps, "foodists" and "eaterists." The eaterists (idealists) contend that no object exists except in relation to eating; hence that everything is constituted a thing by its relation to eating. Special sciences exist indeed which discuss the nature of various sorts of things in relation to _one another_, and hence in legitimate abstraction from the fact that they are all foods. But the discussion of their nature _an sich_ depends upon "eatology," which deals primarily with the problem of the possibility, nature, and extent (or limits) of eating food in general, and thereby determines what food in general, _überhaupt_, is and means. Nay, replies the foodist (realist). Since the eating relation is uniform, it is negligible. All propositions which have any intelligible meaning are about objects just as they are, and in the relations they bear to one another. Foods pass in and out of the relation to eater with no change in their own traits. Moreover, the position of the eaterists is self-contradictory. How can a thing be eaten unless it is, in and of itself, a food? To suppose that a food is constituted by eating is to presuppose that eating eats eating, and so on in infinite regress. In short, to be an eater is to be an eater of food; take away the independent existence of foods, and you deny the existence and the possibility of an eater.