“As the biggest library if it is in disorder is not as useful as a small but well-arranged one, so you may accumulate a vast amount of knowledge but it will be of far less value to you than a much smaller amount if you have not thought it over for yourself; because only through ordering what you know by comparing every truth with every other truth can you take complete possession of your knowledge and get it into your power.”

“It may sometimes happen that a truth, an insight, which you have slowly and laboriously puzzled out by thinking for yourself could have easily have been found already written in a book: but it is a hundred times more valuable if you have arrived at it by thinking for yourself. For only then will it enter your thought system as an integral part and living member, be perfectly and firmly consistent with it and in accord with all its other consequences and conclusions, bear the hue, colour and stamp of your whole manner of thinking, and have arrived at just the moment it was needed ; thus it will stay firmly and forever lodged in your mind.”

“Reading is merely a surrogate for thinking for yourself; it means letting someone else direct your thoughts. Many books, moreover, serve merely to show how many ways there are of being wrong, and how far astray you yourself would go if you followed their guidance. You should read only when your own thoughts dry up, which will of course happen frequently enough even to the best heads; but to banish your own thoughts so as to take up a book is a sin against the holy ghost; it is like deserting untrammeled nature to look at a herbarium or engravings of landscapes.”

“You can do what you will, but in any given moment of your life you can will only one definite thing.”

“We will gradually become indifferent to what goes on in the minds of other people when we acquire a knowledge of the superficial nature of their thoughts, the narrowness of their views and of the number of their errors. Whoever attaches a lot of value to the opinions of others pays them too much honor.”

“To free a man from error is not to deprive him of anything but to give him something: for the knowledge that a thing is false is a piece of truth. No error is harmless: sooner or later it will bring misfortune to him who harbours it. Therefore deceive no one, but rather confess ignorance of what you do not know, and leave each man to devise his own articles of faith for himself.”

“But it is common knowledge that religions don’t want conviction, on the basis of reasons, but faith, on the basis of revelation. And the capacity for faith is at its strongest in childhood: which is why religions apply themselves before all else to getting these tender years into their possession. It is in this way, even more than by threats and stories of miracles, that the doctrines of faith strike roots: for if, in earliest childhood, a man has certain principles and doctrines repeatedly recited to him with abnormal solemnity and with an air of supreme earnestness such as he has never before beheld, and at the same time the possibility of doubt is never so much as touched on, or if it is only in order to describe it as the first step towards eternal perdition, then the impression produced will be so profound that in almost every case the man will be almost incapable of doubting this doctrine as of doubting his own existence, so that hardly one in a thousand will then possess the firmness of mind seriously and honestly to ask himself: is this true?”