Reject popular philosophy. Seneca, Epistles 4.40.4-5

Cynic philosophers and others would occasionally deliver public harangues aimed at critiquing and perhaps bettering the immediate expression of political & social morality in their vicinity. Seneca does not see this kind of discourse as particularly helpful; it happens too quickly to be useful, he thinks, causing people to focus on words instead of behavior, which is the really significant thing. A really useful discourse is one you carry inside for days, months, even years, pondering & assimilating it into your behavior so that you become a more thoughtful agent. This, for Seneca, is philosophy. Slow learning, with the long-term goal of expressing your conscious ideals through deliberate action.

Adice nunc quod quae veritati operam dat oratio incomposita esse debet et simplex: haec popularis nihil habet veri. Movere vult turbam et inconsultas aures impetu rapere, tractandam se non praebet, aufertur: quomodo autem regere potest quae regi non potest? Quid quod haec oratio quae sanandis mentibus adhibetur descendere in nos debet? remedia non prosunt nisi immorantur. Multum praeterea habet inanitatis et vani, plus sonat quam valet. Lenienda sunt quae me exterrent, compescenda quae irritant, discutienda quae fallunt, inhibenda luxuria, corripienda avaritia: quid horum raptim potest fieri? quis medicus aegros in transitu curat? Quid quod ne voluptatem quidem ullam habet talis verborum sine dilectu ruentium strepitus?

Now add the fact that any speech which offers support to truth must be simple and artless. The popular harangue holds none of this, no truth whatsoever. It desires to move the mob, to seize unwary ears and carry them off with its onslaught. It does not offer itself up to be put to the proof, being no sooner spoken than done, and then it is immediately whisked away. How can anyone rule a thing that cannot stop to be ruled? More to our purpose: why should discourses aiming to heal minds sink deep into us? Remedies are useless unless they abide. The popular diatribe contains a great deal of fluff and nonsense, more sound than strength. Things that frighten me must be made weak. Things that bother me must be put down. Things that fail me must be broken to smithereens. Smash luxury! Stop greed! Are any of these words liable to find swift fulfilment in the real world? What doctor heals patients without stopping even to see them? What does such yammering have to offer us? Its flood of words rushing heedless toward oblivion is not even pleasant to hear.