Psychological research is based on philosophical assumptions which are not always explicitly formulated. On the other hand, the results of these investigations affect philosophical thinking and the conception of human nature. For a long time it was a ruling conception in psychology that the essence of human nature consists in the existence of driving mechanisms with homeostatic properties drives or needs – which, principally, are inborn mechanisms modified by learning. The analysis of driving mechanisms founded on psychological and neuro-physiological data, (...) brought about a modification of this traditional view. Starting from the concept of need as an objective phenomenon it can be stated that the higher organisms have a special mechanisms securing the satisfaction of needs. They are drives. These mechanisms do not exist in a ready form in man but only potentially, as an ability to organize a functional unit in result of certain experience. The formation of drives includes: making connections between certain internal stimuli and some forms of activity reducing these stimuli; learning how to find things which are necessary to reduce them; and, finally, the acquisition of the ability to give verbal labels to the occurring processes. In consequence, the final form of a drive is determined by biological and social factors as well as by individual experiences. (shrink)