 But Seneca may agree with psychological monism insofar as he does not distinguish between rational and non-rational powers of the soul (as in fact, arguably neither did the middle Stoics) and still modify a related aspect of the early Stoic account of the soul. Psychological monism implies that there is no distinction between practical and theoretical reason. Knowledge bears directly on action. Indeed, all philosophical knowledge is needed for good decision-making. There is thus, according to Stoic “orthodoxy,” no real distinction between theorizing and aiming to lead a good life (I. Hadot 1969, 101). Seneca brings to bear this aspect of Stoic thought in his own way. For him, studying the arguments for a particular claim will not bring us peace of mind. At the outset of Letter 85, Seneca goes so far as to swear that he does not take pleasure in producing proofs for a piece of doctrine that looms large in his Letters: that virtue alone brings happiness (85.1). His addressee, Lucilius, is presented as urging him to put forward all arguments and objections that are relevant to this issue, and in response, Seneca discusses some of them in Letter 85. But ultimately—and this is evident throughout his writings—this is not enough. Rather, it is important to think through the implications of the Stoic thesis in a variety of practical contexts, so as then to be able to live by it, for example, when one is or is not elected to office, has more or less money than others, and so on (Griffin 2007). One needs to think one’s way through these issues repeatedly—and ultimately, thinking about them in the right way must become a way of life.