The inadequacy of my perception was taken as a de facto inadequacy resulting from the organization of my sensory apparatus; the presence of my body was taken as a de facto presence springing from its constant action on my receptive nervous system; finally the union of soul and body, which was presupposed by these two explanations, was understood, in Cartesian fashion, as a de facto union whose de jure possibility need not be established, because the fact, as the starting point of knowledge, was eliminated from the final result.