  Why did Hume omit the more fundamental arguments for the motivational inertia of reason? He may have reconsidered and rejected them. For example, he may have given up his undefended claim that passions have no representative character, a premise of the Representation Argument on which, as we saw, some of his fundamental anti-rationalist arguments depend. Or he may have retained these views but opted not to appeal to anything so arcane in a work aimed at a broader audience and intended to be as accessible as possible. The moral Enquiry makes no use of ideas and impressions, and so no arguments that depend on that distinction can be offered there, including the Representation Argument. Apparently Hume thought he could show that reason and sentiment rule different domains without using those arguments.