The thesis recently advanced by Mr J. P. Day that ‘Desire (or Will) is irrelevant to Freedom’ is an arresting, even contrary one. And one's first reaction to it may not be unlike Hobbes's on first reading Euclid: ‘“By G—”, sayd he (he would now and then sweare an emphaticall oath by way of emphasis) “This is impossible”’. However, it is hoped to give reason for finding several of Day's propositions somewhat less compelling than Hobbes was to find the propositions of Euclidean geometry. His thesis has and intends implications of ‘great practical importance’. He is concerned with the threat posed to individual liberty by collectivist legislation— though one may be allowed to share this concern without accepting his characterization of the threat. He is also concerned to rebut the claim of tyrannical regimes that they ‘do not really diminish liberty, because they do not really prevent people from doing anything they really want to do’— though again, one may share the concern without finding the rebuttal adequate. Finally, his thesis is intended to offer the possibility of resolving in a ‘higher synthesis’ the contradiction between an ‘Empiricist and Positivist thesis’ and a ‘Rationalist and Idealist antithesis’—but the would-be synthesis succumbs to its own antithesis, taking the form of an anachronistic laissez faire metaphysic. The criticisms to be advanced in this paper stem in part from Day's use of defective argument, and of assertion in place of argument; in part from uneasiness with the assimilation of ‘Desire’ and ‘Will’; but above all from a conviction that a satisfactory account of ‘freedom’ and ‘wanting’ cannot be given without close acquaintance with the various ‘behaviours’ with which the language of ‘freedom’ and ‘wanting’ is actually associated. The basic objection is to Day's employment of a still prevalent semantic procedure which permits the content of behavioural concepts to be arbitrarily determined and treats them as if they were autonomous mental constructs: failings often associated with logical atomism and methodological individualism. The result is to erode and distort the connexion between language and life, and place conceptual content at the mercy of a logic rendered capricious by the inadequacy of the material at its disposal and by misplaced confidence in what it can expect to achieve.