With the rise of the Renaissance and Enlightenment traditions, humanism began to take its place at the center of philosophy. The concept, which is founded on the understanding of man as the absolute subject of historical progress, has ensured the subordination of other natural subjects. As a result, an ethic of thought has emerged which associates intellectual action with the superior good of human. The posthumanist theory, which has emerged in the last quarter of the twentieth century, attempts to make a radical critique of humanism by proposing the dominance of non-human subjects. The theory argues that philosophy should produce a new form of subjectivity that transcends human, asserting that the modern human is just an imagery that damages the material conditions of life, fetishizes historical progress, and dominates technological developments. The purpose of this study is to explain the conceptual set of posthumanism in a systematic way while criticizing the discrepancies in its current state. For this, the methodological and philosophical dimensions of the theory were focused on, and they were discussed using the concepts of subject and ideology: "Subject" meets posthumanism's epistemological struggle against the humanist status quo, while "ideology" meets the political consequences of the given struggle. In the first part of the study, the main discussions of posthumanist theorists and the tensions in the production process of posthuman subjects are examined. In the second part, the theory’s understanding of subjectivity is explained. In the third part, the possibility of a posthumanist ideological paradigm is evaluated. The study concludes that posthumanism might systematically revise its conceptual set and produce new forms of activism to exist in the public sphere.