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.
A man's knowledge may be said to be mature, in other words, when it has reached the most complete state of perfection to which he, as an individual, is capable of bringing it, when an exact correspondence is established between the whole of his abstract ideas and the things he has actually perceived for himself. His will mean that each of his abstract ideas rests, directly or indirectly, upon a basis of observation, which alone endows it with any real value; and also that he is able to place every observation he makes under the right abstract idea which belongs to it.
I observed once to Goethe that when a friend is with us we do not think the same of him as when he is away. He replied, "Yes! because the absent friend is yourself, and he exists only in your head; whereas the friend who is present has an individuality of his own, and moves according to laws of his own, which cannot always be in accordance with those which you form for yourself.
Many books 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.
The nobler and more perfect a thing is, the later and slower it is in arriving at maturity. A man reaches the maturity of his reasoning powers and mental faculties hardly before the age of twenty-eight; a woman at eighteen.
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. You can think about only what you know, so you ought to learn something; on the other hand, you can know only what you have thought about.
We must set limits to our wishes, curb our desires, moderate our anger, always remembering that an individual can attain only an infinitesimal share in anything that is worth having; and that on the other hand, everyone must incur many of the ills of life
Reason deserves to be called a prophet; for in showing us the consequence and effect of our actions in the present, does it not tell us what the future will be?
Will without intellect is the most vulgar and common thing in the world, possessed by every blockhead, who, in the gratification of his passions, shows the stuff of which he is made.