If I make up the definition of a mammal, and then, after inspecting a camel, declare "look, a mammal' I have indeed brought a truth to light in this way, but it is a truth of limited value.

Even great spirits have only their five-fingers' breadth of experience - just beyond it their thinking ceases and their endless empty space and stupidity begins.

We cannot even reproduce our thoughts entirely in words.

Nobody is so constituted as to be able to live everywhere and anywhere; and he who has great duties to perform, which lay claim to all his strength, has, in this respect, a very limited choice. The influence of climate upon the bodily functions extends so far, that a blunder in the choice of locality and climate is able not only to alienate a man from his actual duty, but also to withhold it from him altogether, so that he never even comes face to face with it.

Everything has its limit - iron ore cannot be educated into gold.

Man cannot possess anything as long as he fears death. But to him who does not fear it, everything belongs. If there was no suffering, man would not know his limits, would not know himself.