"Men govern nothing with more difficulty than their tongues, and can moderate their desires more than their words"

"Speculation, like nature, abhors a vacuum"

"As nature preserves a fixed and immutable order; it must clearly follow that miracles are only intelligible as a relation to human opinions, and merely mean events of which the natural cause cannot be explained by a reference to any ordinary occurren"

"Sin cannot be conceived in a natural state, but only in a civil state, where it is decreed by common consent what is good or bad"

"So long as a man imagines that he cannot do this or that, so long as he is determined not to do it; and consequently so long as it is impossible to him that he should do it"

"If you want the present to be different from the past, study the past."

"Pride is pleasure arising from a man's thinking too highly of himself."

"I would warn you that I do not attribute to nature either beauty or deformity, order or confusion. Only in relation to our imagination can things be called beautiful or ugly, well-ordered or confused."

"Be not astonished at new ideas; for it is well known to you that a thing does not therefore cease to be true because it is not accepted by many."

"Will and intellect are one and the same thing"

"The highest activity a human being can attain is learning for understanding, because to understand is to be free"

"Freedom is absolutely necessary for the progress in science and the liberal arts"

"Happiness is a virtue, not its reward"

"Do not weep. Do not wax indignant. Understand."

"I have made a ceaseless effort not to ridicule, not to bewail, not to scorn human actions, but to understand them"

"Ambition is the immoderate desire for power."

"All happiness or unhappiness solely depends upon the quality of the object to which we are attached by love."

"Happiness is a virtue, not its reward."

"Do not weep; do not wax indignant. Understand."

"Fear cannot be without hope nor hope without fear."

"True virtue is life under the direction of reason"

"We feel and know that we are eternal"

"Self - complacency is pleasure accompanied by the idea of oneself as cause"

"Desire is the very essence of man"