The nature of this study is two-fold. Firstly, it is a critique of the ontological assumptions implicit in the neo-Kantian intellectualism which dominates philosophy of mind and cognitive science. As such, it is based upon the criticism against external causalism developed in the last three decades by the Critical Realists in the Anglophone world and some accounts of the history of science and philosophy on the continent. On this basis, the study proposes a materialist approach to the mind which brings together Marxian sociocultural theory of the mind and cognitive science's neurocomputational model. Thus, human beings are conceived as both a social construction and a formal device which can and must be accounted for in terms of productive efficiency rather than any kind of external causality. This study focuses on the materialist ontology of dynamic processes and the embodied nature of thinking, particularly on dialectics as a mediation through language of the internal processes and the external world, and on the actual relevance of Marx's notions of 'passion' or affects and 'practical consciousness'. Secondly, this thesis also studies the nature of the mind in relation to the life of the body, preliminary to a future Ethics whose aim is to consider the form in which passions are used for the political purposes of producing and maintaining, with the manufactured consent of the multitude, authoritarian social formations. Some of the features of such an 'Ethics of Self-valorization' are discussed here. It opposes the transcendental option, considered to be based on a notion of causality which leads it to present the forms of jurisprudence and other ego-ethnocentric discourses as the rational forms. Similar ontological options impede this doctrine from considering the productive role of passions, which are conceived merely as pathological events to be policed by reason and the categorical power of the law. Therefore it does not allow the kind of analysis of the potential of passions that this study aims to make possible.