Our aim in this essay is to present some David Hume’s contributions on reasons for action’s debate. We tried to do this mainly from the discussions presented in the chapters “Of liberty and necessity”, from his An enquiry concerning human understanding, and “Of the general principles of morals” and “Concerning moral sentiment”, both from his An enquiry concerning the principles of morals. Starting from Bernard Williams' provocation in his description of what would be a “sub-Humean” model about reasons for action, we intend to present what the “properly Humean” model of understanding the subject would be. The efforts for this attempt were spent in three different ways, respectively concerning in to reconstruct the Humean argument. The relati...