Theoretical psychology in its present state must try to develop a system of concepts which shows all the characteristics of a Gestalt, in which any p… - Kurt Zadek Lewin

If you want truly to understand something, try to change it.

Working in this field I felt that I had begun a task methodologically and technically sound and necessary, the broader elaboration of which could not be expected for decades. Nevertheless it soon became clear that though these problems are difficult, they are by no means impossible to solve. One had only to clear out a number of hoary philosophical prejudices and to set his scientific goal high enough to arrive at explanation and prediction. Today it can no longer be doubted that the questions set, for example, by psychoanalysis are readily accessible to experimental clarification if only appropriate methods and concepts are employed.

In the psychological fields most fundamental to the whole behavior of living things the transition seems inevitable to a Galileian view of dynamics, which derives all its vectors not from single isolated objects, but from the mutual relations of the factors in the concrete whole situation, that is, essentially, from the momentary condition of the individual and the structure of the psychological situation. The dynamics of the processes is always to be derived from the relation of the concrete individual to the concrete situation, and, so far as internal forces are concerned, from the mutual relations of the various functional systems that make up the individual.