Suicide is not abominable because God prohibits it; God prohibits it because it is abominable.

What are the aims which are at the same time duties? They are perfecting of ourselves, the happiness of others.

[Aristotle formal logic thus far (1787)] has not been able to advance a single step, and hence is to all appearances closed and completed.

Freedom is the alone unoriginated birthright of man, and belongs to him by force of his humanity.

The universal and lasting establishment of peace constitutes not merely a part, but the whole final purpose and end of the science of right as viewed within the limits of reason.

Imagination is a powerful agent for creating, as it were, a second nature out of the material supplied to it by actual nature.

Religion is too important a matter to its devotees to be a subject of ridicule. If they indulge in absurdities, they are to be pitied rather than ridiculed.