This paper is aimed to face two antagonistic approaches about Science: Reality and Truth, Constructionism and Realism; the purpose is to evaluate the strength of their arguments; then we will revise the most important postulates of Constructionism from some fundamental concepts; we will also show some realistic replies to the Constructionism. We finally conclude suggesting the necessity to make a reflexion over these topics in the Social Science research and teaching framework, ergo most of the constructionist theses pervade the theoretical and pedagogical corpus of these disciplines.