The development of Rational Choice Theory in the 20th century arose out of economic theory. Through such thinkers as Homans, Blau and Coleman it has emerged as an important school of thought. The theory focuses upon the rational calculations carried out by individuals guided by self-interest. Post-modernism, another contemporary theory, is in many ways in friction with rational choice theory, for the fundamental capitalist drive espoused by rational choice is seen as nothing but a social construct by the post-modern tradition. Alfred Schutz, a twentieth century phenomenologist, reconciles these two strains of thought to some degree by bringing up the notion of individual perception which encompasses both the social constructs and the drive for self-interest.