Lyotard argues that modernity has come to an end, a postmodern age has begun, and thus the nature and status of knowledge has changed. This claim of Lyotard is based on the assumption that meta-narratives, which are the main foundation of modernity, have collapsed, the creative subject has disappeared, the human world of meaning has been destroyed, radical transformations have occured in the fields of production and technology, and ultimately all the principles on which modern life has constructed have expired. From this point of view, Lyotard claims that the modern way of thinking which is based on reason and knowledge, limits concepts according to basic mental principles, takes universal objective knowledge as a criterion, and enables people to meet on a common ground by determining co-living principles in every respect, has come to an end. According to Lyotard, with the end of modern one, the postmodern condition, which means a new way of life and thinking has emerged. Lyotard believes that the most important reason for the emergence of the Postmodernity is the distrustfullness of modern principles and thoughts. For this reason, according to Lyotard, the modern one has replaced by postmodern; universal perspective, principles and integrity by the blessing of differences have replaced by the glorification of unprincipled, the individual perspective and the dominance of relativity. Lyotard emphasizes that every identity, every culture, every belief, every thought can be legitimated in its own language game and that no comparison can be made between differences. Contrary to some assumptions, this thought of Lyotard brings with it the principle of “anything goes”. However, we must take into question the worth of Lyotard’s master principle or doctrine which is occurred in his works in terms of its affects in entire human life. Therefore, in this study, where such an inquiry will be carried out, in the context of Lyotard's thoughts, we will investigate the postmodernist conception of knowledge and try to evaluate that whether this conception can improve human life which is based on human activities like science, art, philosophy. [ABSTRACT FROM AUTHOR]