 The ascent to this philosophical intuitionism is especially evident in the treatment of common-sense or intuitional morality. As Sidgwick explained in reply to Calderwood’s critical review of the Methods, which asked why he had not simply confined himself “to the consideration of Intuitionism in its most philosophical form,” that tactic “would have led me at once to Utilitarianism: because I hold that the only moral intuitions which sound philosophy can accept as ultimately valid are those which at the same time provide the only possible philosophical basis of the Utilitarian creed. I thus necessarily regard Prof. Calderwood’s Intuitionism as a phase in the development of the Intuitional method, which comes naturally between the crude thought of Butler’s ‘plain man’ and the Rational Utilitarianism to which I ultimately endeavor to lead my reader.” That is, allowing that the morality of common sense is his as well, he must as a philosopher nonetheless