Renouvier insists that we can. Morality deals with facts, although they are not embraced by the categories of number, extension, duration or becoming (as mathematical and physical data), but rather by those of causality, finality and consciousness. The facts “are not the natural being of things, but the _devoir-être_ of the human will, the _devoir-faire_ of persons, and the devoir-être of things in so far as they depend upon persons.”[6] Personal effort, initiative and responsibility lie at the basis of all ethics. Morality is a construction, like every science, partly individual and partly collective; it must lay down postulates, and if it is to justify the claim to be a science, these postulates must be such as to command a _consensus gentium_. Further, if ethics is to be scientifically based it must be independent. In the past this has unfortunately not been the case, for history shows us ethics bound up with some system of religion or metaphysics. If ethics is to be established as a science, Renouvier points out that it must be free from all hypothesis of an irrelevant character, such as cosmological speculations and theological dogmas. Renouvier’s insistence upon the independence of ethics was followed up in an even clearer and more trenchant manner by Guyau in his famous _Esquisse d’une Morale sans Obligation ni Sanction_. [6] _Science de la Morale_, vol. I, p. 10. Although, generally, ethics has suffered by reason of its alliance to theological and metaphysical systems, Renouvier affirms that, in this connection, there is one philosophy which is not open to objection—namely, the Critical Philosophy of Kant. This is because it subordinates all the unknown to phenomena, all phenomena to consciousness, and, within the sphere of consciousness itself, subordinates the speculative reason (_reinen Vernunft_) to the practical reason (_praktischen Vernunft_). Its chief value, according to Renouvier, lies precisely in this maintenance of the primacy of moral considerations.