"Psychology is a very unsatisfactory science. Comparing the vast body of systematised and recognised facts in physics with those in psychology one will doubt the advisability of teaching the latter to anybody who does not intend to become a professional psychologist, one might even doubt the advisability of training professional psychologists. But when one considers the potential contribution which psychology can make to our understanding of the universe, one's attitude may be changed. Science becomes easily divorced from life. The mathematician needs an escape from the thin air of his abstractions, beautiful as they are; the physicist wants to revel in sounds that are soft, mellow, and melodious, that seem to reveal mysteries which are hidden under the curtain of waves and atoms and mathematical equations; and even the biologist likes to enjoy the antics of his dog on Sundays unhampered by his weekday conviction that in reality they - are but chains of machine-like reflexes"

“The general aim of my book has been but to point out a way in which a solution of these numerous problems can be attained. The nature of mental development as it has been revealed to us is not the bringing together of separate elements, but the arousal and perfection of more and more complicated configurations in which both the phenomena of consciousness and the functions of the organism go hand in hand.”

“A complete theory would have to answer, among others, the following questions, given two adjoining retinal areas of different stimulation, under what conditions will the corresponding parts of the behavioural field appear of different whiteness but equal brightness , when of different brightness but equal whiteness? A complete answer to this question would probably supply the key to the complete theory of colour perception in the broadest sense.”

“If an environmental trace is in close connection with the Ego system it will not only be in communication with the particular time structure of that system with which it communicated at the time of its formation; but because of the coherence of the whole temporal Ego system it will be in communication with later strata also.”

“The second factor, equally important, is that of good continuation and good shape. The things which we see have a better shape, are bounded by better contours, than the holes which we might see but do not. Therefore, when in exceptional circumstances these conditions are reversed, we see the hole and not the things, as the shape of a gap between two projecting rocks with sharp profiles, which may look like a face, an animal, or some other object, while the shape of the rock disappears.”

“Things look as they do because of the field organization to which the proximal stimulus distribution gives rise. This answer is final and can be so only because it contains the whole problem of organization itself.”

“Why We See Things and Not the Holes Between Them. We can now attempt an answer to the question why we do so. Two of the factors of organization which we have so far discussed seem to me to be the most important causes of this effect. In the first place, the segregation and unification which occurs will separate areas of different degrees of internal articulation, and according to our law, the more highly articulated ones will become figures, the rest fusing together to form the ground. Look at any landscape photograph. You see the shape of the things, the mountains, and trees and buildings, but not of the sky.”