Psychologists of the sensationalist school have striven to obscure the fundamental distinction which exists between rational thought and the concomitant cerebral imagery. It is, however, far too manifest to escape attention, as the healthy reaction of the modern school of Würzburg indicates. “It cost me great resolution,” says Dr. F. E. Schultze, a member of this school, “to say, that, on the basis of immediate experiment, appearances and sensible apprehensions are not the only things that can be experienced. But finally I had to resign myself to my fate.” (“Beitrag zur Psychologie des Zeitbewusstseins,” p. 277.) But thought is not only distinct from imagery, often there is marked contrast between the two, both as regards subjective, and objective, characters. Thus our thought may be perfectly clear, precise, and pertinent, while the accompanying imagery is obscure, fragmentary, and irrelevant. “What enters into consciousness so fragmentarily, so sporadically, so very accidentally as our mental images,” exclaims Karl Bühler (also of Würzburg), “can not be looked upon as the well-knitted, continuous content of our thinking.” (_Archiv. für die ges. Psychol._, 9, 1907, p. 317.) The same contrast exists with respect to their objective characters. Imagination represents by means of one and the same image what reason represents by means of two distinct concepts, _e.g._ an oasis and a mirage; and, _vice versa_, reason represents under the single general concept of a rose objects that imagination is forced to represent by means of two distinct images, _e.g._, a yellow, and a white rose. Imagery depicts only the superficial or exterior properties of an object, whereas thought penetrates beneath the phenomenal surface to interior properties and supersensible relationships. The sensory percept apprehends the existence of a fact, while the rational concept analyzes its nature. Hence sense-perception is concerned with the _reality of existence_, while thought is concerned with the _reality of essence_.