“[B]eauty is always an affair of knowledge.”

“To free a man from error is to give, not to take away. Knowledge that a thing is false is a truth. Error always does harm; sooner or later it will bring mischief to the man who harbors it.”

“The fundament upon which all our knowledge and learning rests is the inexplicable.”

“It is easy to understand that in the dreary middle ages the Aristotelian logic would be very acceptable to the controversial spirit of the schoolmen, which, in the absence of all real knowledge, spent its energy upon mere formulas and words, and that it would be eagerly adopted even in its mutilated Arabian form, and presently established as the centre of all knowledge.”

“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.”

“What give all that is tragic, whatever its form, the characteristic of the sublime, is the first inkling of the knowledge that the world and life can give no satisfaction, and are not worth our investment in them. The tragic spirit consists in this. Accordingly it leads to resignation.”

“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.”