本文主張，習性與偶成性之間的來回拉扯作用，是我們分析現代化社會生活形式多元化問題的主要思考軸線。透過此二概念的對比觀察，可以激發更多的思考空間。為了充分掌握此二概念的意涵，本文回到一般社會學理論關於此二概念的討論。這正是本文介紹Bourdieu與Luhmann二位社會學家思想的主要出發點。希望藉此破除一些關於此二概念的刻板印象，也凸顯理論分析的一些選擇性親近。

　　　　　The study compares the important divergency between Pierre Bourdieu's theory of practice and Niklas Luhmann's systems theory. It focuses on two central concepts: Bourdieu's habitus and Luhmann's contingency. The reasons are following: Firstly, these contradictory concepts provide us to examine--and go beyond--the traditional dualism of subjectivism and objectivism. It would de seen that Bourdieu uses a double movements between the internalization of externality and the externalization of internality to avoid to come to this dead-end street, and that Luhmann introduces a paradoxical situation of a dilemma to dissolve this controversial problem. Secondly, using this conceptual opposition in this way is to emphasize that in view of social structure, individual action, and social evolution there exists a dividing line between Bourdieu and Luhmann. Finally, on this basis of these two central concepts the study tries to connect today's discussion of the modern forms of life with the general sociological theory.