Moral letters to Lucilius/Appendix
Ep. xciv. deals, on the whole, with the question whether doctrines without precepts are enough for the student and the philosopher; Ep. xcv. whether precepts without doctrines will suffice. Seneca concludes that they are both necessary and are complementary to one another, especially in view of the complicated life which one is called upon to live, with its many duties and choices. The terms discussed, with some of the Greek original definitions, may be summed up as follows:-
(1) The outward expressions of ἐπιστήμη (scientia, knowledge) and of the κοιναὶ ἔννοιαι (notiones communes, προλήψεις, innate ideas) are found in the form of ἀξιώματα (pronuntiata, incontrovertible statements), δόγματα (placita, decreta, scita, doctrines, tenets, dogmas, principles). Determined by ὅροι (definitiones, definitions), they are tested by their ἀξία (honestum, moral value), by the κριτήριον (norma iudicii, standard of judgement) or κανών (lex, regula, etc.), and by the ὀρθὸς λόγος (recta ratio, universal law, etc.). By such means the doctrines of philosophy are contrasted with δόξα (opinio) and with a κατάληψις (cognitio or comprehensio) which falls short of completeness and perfection. Conduct which results from a thorough understanding and performance of such doctrines is κατόρθωμα (τέλειον καθῆκον, perfectum officium, "absolute duty".
(2) The pars praeceptiva (παραινετική) of philosophy, which deals with "average duty" (καθῆκον, commune or medium officium), is approved, among others, by Posidonius, Cicero (see the De Officiis), and Seneca. It is related to active living and to the ἀδιάφορα (media or indifferentia) (see Subject Index) which play so large a rôle in the individual's daily existence. This department of "counsel," "admonition," or "advice" has many forms. For παραίνεσις (monitio) are needed: the λόγος προτρεπτικός (exhortatio), τόπος ὑποθετικός (suasio), ἀποτροπή (dissuasio), ἐπιτίμησις (obiurgatio), λόγος παραμυθητικός (consolatio), αἰτιολογία (causarum inquisitio), ἠθολογία (descriptio), and all the gamut of precepts which run from blame to praise. These are reinforced by ἀπόδειξις (probatio, argumentum, proof) and by such helps as χρεῖαι, ἀπομνημονεύματα (sententiae, proverbs, maxims).
By such stages of advancement, προκοπή (progressio), and relying upon παραδείγματα (exempla), one rises, through practical precepts and the observance of duties, to an appreciation of the virtues, the contemplative mastery of the Universe, and to the Supreme Good, conformity with Nature (ὁμολογουμένως τῇ φύσει ζῆν, vivere convenienter naturae).