In 1995 the publication of Marleen Rozemond’s paper Descartes’s Case for Dualism has triggered the revival of the discussion on his argument in favor of the real distinction between body and soul among the Anglo-Saxon scholars. In particular the discussion then resumed was on the necessity of introducing a hidden premise (the so called the attribute premise) in order to regain its probatory character. This debate has reflected on the Cartesian studies in Brazil and my objective in this text is to bring to the debate two texts still unexplored related to this interpretative problem. My hypothesis is that the attempts to justify the thesis that the substance has exactly one principal attribute have not yet better succeeded because they underestimated the contribution brought about by the transformation of the notion of nature entailed by the introduction of the concept of principal attribute. Understanding the Cartesian proof of substantial dualism, and more particularly the “attribute premise”, would involve, I suggest, the thesis according to which the concept of principal attribute, insofar as it expresses the essence of the substance, is not – and cannot be – according to Descartes, an abstract universal, but rather a particular nature.