Seneca, Letters to Lucilius
33.7-11 (tr. Richard M. Gummere):
 For it is disgraceful even for an old man, or one who has sighted old age, to have a note-book knowledge. "This is what Zeno said." But what have you yourself said? "This is the opinion of Cleanthes." But what is your own opinion? How long shall you march under another man's orders? Take command, and utter some word which posterity will remember. Put forth something from your own stock.
 For this reason I hold that there is nothing of eminence in all such men as these, who never create anything themselves, but always lurk in the shadow of others, playing the role of interpreters, never daring to put once into practice what they have been so long in learning. They have exercised their memories on other men's material. But it is one thing to remember, another to know. Remembering is merely safeguarding something entrusted to the memory; knowing, however, means making everything your own; it means not depending upon the copy and not all the time glancing back at the master.
 "Thus said Zeno, thus said Cleanthes, indeed!" Let there be a difference between yourself and your book! How long shall you be a learner? From now on be a teacher as well! "But why," one asks, "should I have to continue hearing lectures on what I can read?" "The living voice," one replies, "is a great help." Perhaps, but not the voice which merely makes itself the mouthpiece of another's words, and only performs the duty of a reporter.
 Consider this fact also. Those who have never attained their mental independence begin, in the first place, by following the leader in cases where everyone has deserted the leader; then, in the second place, they follow him in matters where the truth is still being investigated. However, the truth will never be discovered if we rest contented with discoveries already made. Besides, he who follows another not only discovers nothing but is not even investigating.
 What then? Shall I not follow in the footsteps of my predecessors? I shall indeed use the old road, but if I find one that makes a shorter cut and is smoother to travel, I shall open the new road. Men who have made these discoveries before us are not our masters, but our guides. Truth lies open for all; it has not yet been monopolized. And there is plenty of it left even for posterity to discover.
 Turpe est enim seni aut prospicienti senectutem ex commentario sapere. 'Hoc Zenon dixit': tu quid? 'Hoc Cleanthes': tu quid? Quousque sub alio moveris? impera et dic quod memoriae tradatur, aliquid et de tuo profer.
 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 quare audiam quod legere possum? 'Multum' inquit 'viva vox facit.' Non quidem haec quae alienis verbis commodatur et actuari vice fungitur.
 Adice nunc quod isti qui numquam tutelae suae fiunt primum in ea re sequuntur priores in qua nemo non a priore descivit; deinde in ea re sequuntur quae adhuc quaeritur. Numquam autem invenietur, si contenti fuerimus inventis. Praeterea qui alium sequitur nihil invenit, immo nec quaerit.
 Quid ergo? non ibo per priorum vestigia? ego vero utar via vetere, sed si propiorem planioremque invenero, hanc muniam. Qui ante nos ista moverunt non domini nostri sed duces sunt. Patet omnibus veritas; nondum est occupata; multum ex illa etiam futuris relictum est.
Arthur Schopenhauer, Parerga and Paralipomena
II, Kap. XXII, § 260 (tr. E.F.J. Payne):
On the other hand, to scare away our own original and powerful ideas in order to take up a book, is a sin against the Holy Ghost. We then resemble the man who runs away from free nature in order to look at a herbarium, or to contemplate a beautiful landscape in a copper engraving.
Even if occasionally we had been able very easily and conveniently to find in a book a truth or view which we very laboriously and slowly discovered through our own thinking and combining, it is nevertheless a hundred times more valuable if we have arrived at it through our own original thinking. Only then does it enter into the whole system of our ideas as an integral part and living member; only then is it completely and firmly connected therewith, is understood in all its grounds and consequents, bears the colour, tone, and stamp of our whole mode of thought, has come at the very time when the need for it was keen, is therefore firmly established and cannot again pass away.
Hingegen die eigenen, urkräftigen Gedanken verscheuchen, um ein Buch zur Hand zu nehmen, ist Sünde wider den heiligen Geist. Man gleicht alsdann Dem, der aus der freien Natur flieht, um ein Herbarium zu besehn, oder um schöne Gegenden im Kupferstiche zu betrachten.
Wenn man auch bisweilen eine Wahrheit, eine Einsicht, die man mit vieler Mühe und langsam durch eigenes Denken und Kombiniren herausgebracht hat, hätte mit Bequemlichkeit in einem Buche ganz fertig vorfinden können; so ist sie doch hundert Mal mehr werth, wenn man sie durch eigenes Denken erlangt hat. Denn nur alsdann tritt sie als integrirender Theil, als lebendiges Glied, ein, in das ganze System unserer Gedanken, steht mit demselben in vollkommenem und festem Zusammenhange, wird mit allen ihren Gründen und Folgen verstanden, trägt die Farbe, den Farbenton, das Gepräge unsrer ganzen Denkweise, ist eben zur rechten Zeit, als das Bedürfniß derselben rege war, gekommen, sitzt daher fest und kann nicht wieder verschwinden.
Related post: Quotations