The development of human history is a manifestation of the furtherance of individual liberties. Looking back, the advancement of individual liberties has never been easy. Human society as whole has conservative propensities; prevailing mainstream ideas and established institutions are stumbling blocks of the advancement of human liberties. The author of this essay takes the process of decriminalization of male sexuality as an example to demonstrate that the demand of a wider scope of individual liberties is irresistible; hence this demand should justifiably be given a special consideration. The main part of this essay gives an account of the debate between Lord Devlin and Professor Hart, held in late 1950 and early 1960. The debate centers on issues concerning the function of law and the relation between law and morality. From the stance of Mill's ”harm principle”, the author takes side with Professor Hart and suggests that individual liberties are the trump of human value.