GESTALT ("figure," "form," "shape"), an expression intro duced into psychology by Christian Ehrenfels in 189o, to indicate the character of a perception as a unity. Thus the seeing of a. square does not consist in seeing four equal straight lines enclosing four right angles, but is the perception of the square as a whole. In the same way a melody is the totality of a series of tones, not the sum of the separate tones. Bertrand Russell defines Gestalt psychologie as the psychology of form, dealing with the apprehen sion of wholes. He says that "reading is a case in point. Whether we read black letters on white paper or white letters on a black board is a matter which we hardly notice; it is the forms of the letters that affect us, not their colour or their size." And again, "as we have already seen in connection with Gestaltpsychologie and with sentences, the causal unit is often a configuration which cannot be broken up without losing its distinctive causal proper ties." He adds a personal illustration : "In writing a book, my own experience—which I know is fairly common, though by no means universal—is that for a time I fumble and hesitate, and then suddenly I see the book as a whole, and have only to write it down as if I were copying a completed manuscript" (Philosophy, 1927).
See W. Kohler, Die physischen Gestalten in Ruhe and im stationaren Zustand (192o) ; G. E. Muller, Komplextheorie and Gestalttheorie