This text intends, firstly, to illustrate Brazilian interpretation of Descartes’s ethical viewpoint, with emphasis on Lívio Teixeira’s contribution. Secondly, the author extends his interpretation showing how Descartes’s thought is based on ethical viewpoint. Not only the ultimate purpose of all philosophy is given by the struggle to know how one should act, but also the struggle itself is understood as an ethical act. Therefore, searching for the truth never loses its ethical dimension and, besides, is always a component of virtue, as measured by the will leading our capacity for judgement. The definition of virtue itself was thus unified by Descartes; thinking of the best manner (which is already in some way acting) to act (in a more common meaning of this term). From this perspective, we couldn’t say that the French philosopher, at the end of his life, elaborated firstly a “definitive moral” – a term never used by him and one opposite to the indetermination of acting suitable to morality. Secondly, neither a “scientific moral” – although there is a scientific basis to formulate a moral (overestimated sometimes by the philosopher), its dimension of uncertainty and the impossibility of total determination escapes from the field of science. Consequently, we also can’t say that Descartes formulated a “perfect moral”, which is suitable to God, because only He is perfectly wise. We can only say that the philosopher presented a sketch of the best possible “perfect moral”.