The first chapter considers Seneca’s views on the life of studious leisure (otium) in relation to the therapeutic purpose that he claims for all his philosophical writings. In his essay On Leisure, Seneca explores several standard defenses of the contemplative life (Aristotle’s βίος θεωρητικός), indicating clearly that such theoretical pursuits as astronomy and metaphysics are worthwhile pursuits in their own right. Yet there are tensions in his position, for he also suggests that the expenditure of time that philosophy requires is justified primarily by the moral benefits it conveys to oneself and, through the medium of writing, to future generations. In the Letters on Ethics, the latter claim is put forward as the very reason for the book’s existence, a generic imperative to which the entire content should refer. Consequently, those purely theoretical investigations that (nonetheless) appear in the Letters are present on sufferance and must be excused by a series of deliberately transparent rhetorical devices.