The heart has its reasons of which reason knows nothing.
Justice and truth are too such subtle points that our tools are too blunt to touch them accurately.
One must know oneself. If this does not serve to discover truth, it at least serves as a rule of life and there is nothing better.
Nothing gives rest but the sincere search for truth.
Too much and too little wine. Give him none, he cannot find truth give him too much, the same.
We know the truth, not only by the reason, but also by the heart.
Contradiction is not a sign of falsity, nor the lack of contradiction a sign of truth.
Truth is so obscure in these times, and falsehood so established, that, unless we love the truth, we cannot know it.
I have made this letter longer than usual, only because I have not had the time to make it shorter.
To have no time for philosophy is to be a true philosopher.
The strength of a man's virtue should not be measured by his special exertions, but by his habitual acts.
Atheism shows strength of mind, but only to a certain degree.
Thus so wretched is man that he would weary even without any cause for weariness... and so frivolous is he that, though full of a thousand reasons for weariness, the least thing, such as playing billiards or hitting a ball, is sufficient enough to amuse him.
If we must not act save on a certainty, we ought not to act on religion, for it is not certain. But how many things we do on an uncertainty, sea voyages, battles!
Human beings must be known to be loved but Divine beings must be loved to be known.
Justice and power must be brought together, so that whatever is just may be powerful, and whatever is powerful may be just.
Man's greatness lies in his power of thought.
Can anything be stupider than that a man has the right to kill me because he lives on the other side of a river and his ruler has a quarrel with mine, though I have not quarrelled with him?
Our soul is cast into a body, where it finds number, time, dimension. Thereupon it reasons, and calls this nature necessity, and can believe nothing else.
Custom is our nature. What are our natural principles but principles of custom?