Philosophy needs action. Seneca, Epistles 4.33.8-9

Seneca is not a fan of would-be philosophers who refuse to know their own lives, who dedicate themselves to memorize what others did or said instead of doing anything for themselves.

Omnes itaque istos, numquam auctores, semper interpretes, sub aliena umbra latentes, nihil existimo habere generosi, numquam ausos aliquando facere quod diu didicerant. Memoriam in alienis exercuerunt; aliud autem est meminisse, aliud scire. Meminisse est rem commissam memoriae custodire; at contra scire est et sua facere quaeque nec ad exemplar pendere et totiens respicere ad magistrum. Hoc dixit Zenon, hoc Cleanthes. Aliquid inter te intersit et librum. Quousque disces? iam et praecipe. Quid est et quare audiam quod legere possum? Multum inquit viva vox facit. Non quidem haec quae alienis verbis commodatur et actuari vice fungitur.

All the craven mob whose philosophy is interpretation rather than action, since they hide under the shadow of others in lieu of thinking for themselves—I judge them to lack all true nobility, as they have never dared to put any of their lessons to action, despite having so much time in which to do so. They have worked hard to memorize the words and lives of others, but memorizing isn't the same as knowing. Memorizing is holding a thing committed to memory, where you watch it. But knowing is doing all your own business, managing each of your own affairs without deferring constantly to any example or teacher. “Zeno said this! Cleanthes said that!” Something should be there between you and the book. How long will you insist on studying? Take the damn test already. Why should I wait to hear in person what I am perfectly capable of reading for myself? “The live voice of the master makes a great difference,” some eternal pupil says. The pupil's voice is certainly not of any consequence, since it is always mouthing someone else's words, changing motivation with each sentence.