After having examined the relations of the consciousness with its objects, let us see what concerns the perception, by the consciousness, of the relations existing between these objects themselves. The question is to ascertain whether the a priorists are right in admitting that the establishment of these relations is the work of the consciousness. The rôle of synthetic power that is thus attributed to consciousness is difficult to conceive unless we alter the definition of consciousness to fit the case. In accordance with the definition we have given and the idea we have of