本文首先討論理性主義陣營中新現實主義和新自由主義在1980年代的激辯，而引出批判理論的不滿與介入。這就是西方國際關係理論背後哲學思維的爭執，涉及到本體論、知識論和方法論的歧異。這是理論界大鳴大放的時期。在批判理論抨擊理性主義之際，全球冷戰突然結束，蘇聯崩解，東歐諸國紛紛變成「新民主」，國際局勢的丕變，為傳統國關學說無法理解與闡釋。這就促成建構主義的生成。這一建構主義理論的轉折同結構兼行動理論之盛行有關，更可以看作批判理論的延申。由於建構主義重視理念，而非物質因素在國際政治上扮演的角色，而招致批評。對此抨擊建構主義者也有合理的反駁與辯解。要之，建構主義所強調的規範、文化、認同體、國際互動相互建構的「意義」和理論是國際局勢的決定因素，這種主張強化其學科當成整體之可能性，也豐富建構主義與理性主義的內涵，是協助吾人對21世紀國際政治更為深刻理解的工具。

This article deals with the hot debates on international relations (IR) between neorealists and neoliberalists within the camp of rationalism in the 1980s. From those academic controversies arose not only the critical theory but also the constructivist school of world politics. In fact, the so-called constructivism in IR theory evolves and develops out of the polemics with the critical theory. It can be regarded as the extension and enlargement of the critical theory. The constructive emphasis on ideational factors in IR provokes the critiques of the adequacy of its interpretation of world affairs. However, in a rapidly changing global society IR are not only constituted by material interests but also shaped by human ideas and views. Indeed, we live in an age of information and communication. Our world is constituted by various material and ideational forces that make the pluralist and intersubjective outlook meaningful. Finally, the treatise discusses the strength as well as the deficiencies of the modern and postmodern constructivism and reevaluates their contribution to the further development of IR theories.