Whatsoever is contrary to nature is contrary to reason, and whatsoever is contrary to reason is absurd.

• He alone is free who lives with free consent under the entire guidance of reason.
• Only that thing is free which exists by the necessities of its own nature, and is determined in its actions by itself alone.
• 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.
• There is no hope unmingled with fear, and no fear unmingled with hope.
• Fear cannot be without hope nor hope without fear.
• Freedom is absolutely necessary for the progress in science and the liberal arts.
• 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.
• Fear cannot be without hope nor hope without fear.
• There is no hope unmingled with fear, and no fear unmingled with hope.