To begin with, abstract terms are one and all the result of the process of abstraction. This process consists in our picking out some common feature or quality from a great variety of objects, and giving it a name in order to fix it in our memory. For example, fire, the inside of ripe watermelon, and the outside of ripe cherries may all be called _red_. The concept, or abstract term, “red” can thereafter be used on occasion as a gestural sign for all these various objects when their color is being signified. Moreover, the process of abstracting these common qualities is itself a motor process. It is, physiologically speaking, the same sort of activity as collecting postage stamps or beetles’ wings. Indeed, the simplest perception of any concrete object, any red object, for example, involves motor activity of a highly elaborate character. When we look at such an object, not only is the retina of the eye stimulated, but various muscles and glands are simultaneously activated to an elaborate transformation of energy. Likewise, when we hear, taste, smell, or have any other perception, other characteristic transformations of energy are taking place through the arousal of action-patterns. Now we have just stated that abstract terms are derived from the multifarious perception of concrete objects. In what, then, does the meaning of abstract terms consist? It consists in their function of recalling some of the particular experiences from which they were derived. Such an abstract word as “red” has, then, a meaning for us simply because it arouses in any of its phases that particular action-pattern which all sorts of red things have stimulated in us. This same principle may now be applied to show how even the meaning which attaches to the words we employ to convey judgments of value may be explained in physiological terms. For the highly abstract character which the words _cheap_, _beautiful_, and _good_ seem at times to possess is simply due to the fact that at the mention of any such word we are simultaneously stimulated to so great a variety of actions that we are unable to follow any one of them through to its conclusion. When such a condition persists, the meaning is said to be vague.