This actual world of what is knowable, in which we are and which is in us, remains both the material and the limit of our consideration.

Any book, which is at all important, should be reread immediately

If there is anything in the world that can really be called a man's property, it is surely that which is the result of his mental activity.

There is only one inborn erroneous notion ... that we exist in order to be happy ... So long as we persist in this inborn error ... the world seems to us full of contradictions. For at every step, in great things and small, we are bound to experience that the world and life are certainly not arranged for the purpose of maintaining a happy existence ... hence the countenances of almost all elderly persons wear the expression of ... disappointment.

Life is short and truth works far and lives long: let us speak the truth.

There is in the world only the choice between loneliness and vulgarity. All young people should be taught now to put up with loneliness ... because the less man is compelled to come into contact with others, the better off he is.

Pride is an established conviction of one’s own paramount worth in some particular respect, while vanity is the desire of rousing such a conviction in others, and it is generally accompanied by the secret hope of ultimately coming to the same conviction oneself. Pride works from within; it is the direct appreciation of oneself. Vanity is the desire to arrive at this appreciation indirectly, from without.