So act that anything you do may become universal law.

Animals... are there merely as a means to an end. That end is man.

[R]eason is... given to us as a practical faculty, that is, as one that influences the will.

Morality is not properly the doctrine of how we may make ourselves happy, but how we may make ourselves worthy of happiness.

Man's greatest concern is to know how he shall properly fill his place in the universe and correctly understand what he must be in order to be a man.

Sincerity is the indispensable ground of all conscientiousness, and by consequence of all heartfelt religion.

Manners or etiquette ('accessibility, affability, politeness, refinement, propriety, courtesy, and ingratiating and captivating behavior') call for no large measure of moral determination and cannot, therefore, be reckoned as virtues. Even though manners are no virtues, they are a means of developing virtue.... The more we refine the crude elements in our nature, the more we improve our humanity and the more capable it grows of feeling the driving force of virtuous principles.