The primary significance of the so-called 'Schutz-Parsons debate' seems that this 'debate' clarifies the contents of the meta-theory of sociology to some extent. This paper purposes to show the contents of the 'theory of motives' as the meta-theory of sociology through the following analyses: (1) To explain the outline of Schutz's 'theory of motives'. This explanation makes clear the shortcomings of this 'theory'. (2) To show the element that distinguishes Schutz's 'theory of motives' from Parsons' 'action frame of reference'. This element must be the center of the 'theory of motives'. (3) To examine C. W. Mills' 'theory of motives'. This examination makes clear that Mills' 'theory of motives' complements Schutz's. These analyses show that the 'theory of motives' is composed of the following elements: (1) To refer to the knowledge that lay actors use to understand actions of others. The experiences of social scientists as lay actors make this reference possible. (2) The same way of typification as lay actors use, which is to construct personal types and course-of-action types through their coordinations with typical because motives and in-order- to motives. (3) The relevance that makes possible that social scientists understand lay actors' actions. This relevance provides some systems of 'vocabularies of motive'.