Text of the lecture invited by the Faculty of Philosophy at Charles-University in Prague on 4th May 1990. -- Seeking the common denominators of various schools of Buddhism and modern psychology is a means of the present comparative study. -- In order to proceed with the comparison, four main streams of modern scientific psychology are characterized: first, the positivistic school of behaviorism which conceives of man as only reacting machine and neglects whatever ethical considerations; second, the psychoanalysis which is oriented chiefly towards the psychopathology but also discovers the relevance of the myths and rituals for life coping; third, the humanistic psychology oriented towards the self-realization of man; and fourth, the transpersonal psychology studying also the spiritual values and techniques of meditation, analysing the cosmic consciousness and the phenomena of transcending the human condition. ...