There has been a constant debate between cognitive and social camps in SLA. In 1997 and 2007, The Modern Language Journal invited scholars to enumerate their diverse viewpoints, published in the Focus Issue. In 2014, Studies in Second Language Acquisition invited scholars from both camps to continue this dialogue and reconceptualize the key issues in a special article. Dividing the quarter century SLA research into three stages (the stage of debates, the stage of mutual concern and the stage of dialogues), this paper, therefore, aims at discovering the nature of the debates by illustrating the origin and fundamental concepts of the postmodernism. This trend contributes to the diverse conceptualization of research participants, the relationship between researchers and participants and research methods.