Discourtesy does not spring merely from one bad quality, but from several--from foolish vanity, from ignorance of what is due to others, from indolence, from stupidity, from distraction of thought, from contempt of others, from jealousy.

Avoid making yourself the subject of conversation.

There is speaking well, speaking easily, speaking justly and speaking seasonably: It is offending against the last, to speak of entertainments before the indigent; of sound limbs and health before the infirm; of houses and lands before one who has not so much as a dwelling; in a word, to speak of your prosperity before the miserable; this conversation is cruel, and the comparison which naturally arises in them betwixt their condition and yours is excruciating.

Wit is the god of moments, but Genius is the god of ages.

He who excels in his art so as to carry it to the utmost height of perfection of which it is capable may be said in some measure to go beyond it: his transcendent productions admit of no appellations.

Logic is the technique by which we add conviction to truth.

When what you read elevates your mind and fills you with noble aspirations, look for no other rule by which to judge a book; it is good, and is the work of a master-hand.