Hume's first work, A Treatise of Human Nature, has traditionally received the lion's share of scholarly attention, at the expense of his later and more polished texts. The tide has started to shift in recent years, with the result that Hume's two Enquiries - his mature investigations of the understanding and morals - are now recognised as important works in their own right (though most commentators still continue to prefer the Treatise). With regard to Hume's work on the passions, however, Book~2 of the Treatise still commands all of the attention.
In this thesis, I defend two important claims. The first is that Hume has a mature philosophy of emotion, significantly different - indeed, significantly improved - from that of the Treatise. Most strikingly, it is anti-egoist and anti-hedonist about motivation, where the Treatise had espoused a Lockean hedonism and egoism. In parts it is also more cognitivist, and although Hume remains as opposed to moral rationalism as he ever was, his arguments in support of this opposition are very different.
The second claim is that Hume's mature philosophy of emotion is to be found, not in the Dissertation on the Passions, but rather in the full set of Four Dissertations in which this work first appeared, including also the Natural History of Religion, Of Tragedy, and Of the Standard of Taste. The passions, I argue, form the unifying theme of this collection, which is in effect Hume's Enquiry concerning the Passions. I maintain that they are profitably studied together on this understanding, and my thesis is offered as the first such study
