I would like to develop a few critical observations on some substantive moral ideas propounded in Professor R. M. Hare's Freedom and Reason a work where formal and substantive moral arguments are blended in an attractive and plausible, though at times somewhat exasperating, mixture. Hare's formal doctrines, the celebrated theses of prescriptivity and universalizability, will not as such interest me here, though I shall have to take notice of at least one of them, viz. universalizability, in so far as it has a bearing on what I take to be Hare's substantive position. The arguments in Freedom and Reason are compounded of Kantian and utilitarian elements, and culminate in Hare's conceptualization of two antithetical types of person, whom he calls respectively the ‘liberal’ and the ‘fanatic’. This distinction itself is based on a rigid and uncompromising dichotomy of ‘interest’ and ‘ideal’, and it is on this dichotomy that Hare's substantive moral doctrine hinges. Hare's argument is that the morally good person is one who subordinates his ideal to a moral principle that takes interests into account, in contradistinction to the fanatic who allows interests to be overridden by his ideal. There is much to recommend in this doctrine, and distinctions of this nature can and ought to be drawn. But the way in which it is done in Hare's work opens up fresh doubts and fails to solve some fundamental problems. As I do not think that his distinction between ‘interest’ and ‘ideal’ is tenable, I cannot agree wholly to the predominantly formal manner in which Hare deals with the important question of distinguishing between liberalism and fanaticism. The upshot of my arguments is that this distinction can only be made intelligible in substantive terms. Although I cannot here offer a positive alternative to Hare beyond some oblique hints at the end, my critical remarks on Hare's doctrine ought at least to go some way in establishing the need for such an alternative.