God, freedom, and immortality are untenable in the light of pure reason..

All our knowledge begins with the senses, proceeds then to the understanding, and ends with reason. There is nothing higher than reason..

Only the descent into the hell of self-knowledge can pave the way to godliness..

Two things strike me dumb: the infinite starry heavens, and the sense of right and wrong in man..

To be beneficent when we can is a duty; and besides this, there are many minds so sympathetically constituted that, without any other motive of vanit….

All false art, all vain wisdom, lasts its time but finally destroys itself, and its highest culture is also the epoch of its decay..

It is not necessary that whilst I live I live happily; but it is necessary that so long as I live I should live honourably..

Religion is the recognition of all our duties as divine commands..

But although all our knowledge begins with experience, it does not follow that it arises from experience..

Human reason has the peculiar fate in one species of its cognitions that it is burdened with questions which it cannot dismiss, since they are given ….

A categorical imperative would be one which represented an action as objectively necessary in itself, without reference to any other purpose..

cruelty to animals is contrary to man's duty to himself, because it deadens in him the feeling of sympathy for their sufferings, and thus a natural t….

Maximum individuality within maximum community.

Philosophical knowledge is the knowledge gained by reason from concepts ; mathematical knowledge is the knowledge gained by reason from the construct….

Fallacious and misleading arguments are most easily detected if set out in correct syllogistic form..

Man relates to material things through direct insight rather than reason..

We come no nearer the infinitude of the creative power of God, if we enclose the space of its revelation within a sphere described with the radius of….

Feminine traits are called weaknesses. People joke about them; fools ridicule them; but reasonable persons see very well that those traits are just t….

It is presumed that there exists a great unity in nature, in respect of the adequacy of a single cause to account for many different kinds of consequ….

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

Even the song of birds, which we can bring under no musical rule, seems to have more freedom, and therefore more for taste, than a song of a human be….