Men are disturbed not by the things which happen, but by the opinion about the things.

men’s actions are the best guides to their thoughts

A man may imagine things that are false, but he can only understand things that are true.

Men can know the nature of things

Men are disturbed, not by things, but by the principles and notions which they form concerning things.

Man's desires are limited by his perceptions; none can desire what he has not perceiv'd.

What disturbs men's minds is not events but their judgements on events:

Men are not afraid of things, but of how they view them.

When a man's position in life depends upon his having a certain opinion, that's the opinion he will have.

A man may not know what will happen as a result of other people’s actions or as the result of unknown causes, but he always knows all possible results of his own actions.

man’s beliefs were his own affair, so long as they did not interfere with the liberty of others.

Men have their virtues and their vices, their heroisms and their perversities; men are neither wholly good nor wholly bad, but possess and practice all that there is of good and bad here below. Such is the general rule. Temperament, education, the accidents of life, are modifying factors. Outside of this, everything is ordered arrangement, everything is chance. Such has been my rule of expectation and it has usually brought me success.

A man is rational in proportion as his intelligence informs and controls his desires.

Men are mistaken in thinking themselves free; their opinion is made up of consciousness of their own actions, and ignorance of the causes by which they are determined.