In this paper I intend to reconstruct the weight of rational and non rational factors in ethical controversies and to highlight the mixed bequest this controversy left to 20th century analytic ethics. I argue that the structure of the controversy includes ‘Kuhnian’ factors, rhetoric and pragmatic dimensions, and that a consistent self-criticism of his own previous views may be detected in Mill’s writings published after the controversy. I argue that the controversy’s bequest for analytic ethics includes: (i) anti-empiricist elements, which (...) are what Sidgwick has taken from Whewell without paying due acknowledgement; (ii) consequentialist elements (impossibility of establishing what is duty in the real case, impossibility of solving moral dilemmas), which are what Sidgwick has taken over from Mill, on the latter’s authority and without due scrutiny of Whewell’s counter-arguments. (shrink)