The soul, when accustomed to superfluous things, acquires a strong habit of desiring things which are neither necessary for the preservation of the individual nor for that of the species. This desire is without limit, whilst those which are necessary are few in number and restricted within certain limits; but what is superfluous is without end...

When I have a difficult subject before me — when I find the road narrow, and can see no other way of teaching a well established truth except by pleasing one intelligent man and displeasing ten thousand fools — I prefer to address myself to the one man, and to take no notice whatever of the condemnation of the multitude; I prefer to extricate that intelligent man from his embarrassment and show him the cause of his perplexity, so that he may attain perfection and be at peace.

If a person studies too much and exhausts his reflective powers, he will be confused, and will not be able to apprehend even that which had been within the power of his apprehension. For the powers of the body are all alike in this respect.