Freedom is the alone unoriginated birthright of man, and belongs to him by force of his humanity; and is independence on the will and co-action of every other in so far as this consists with every other person's freedom.

Act only according to that maxim whereby you can at the same time will that it should become a universal law.

Criticism alone can sever the root of materialism, fatalism, atheism, free-thinking, fanaticism, and superstition, which can be injurious universally; as well as of idealism and skepticism, which are dangerous chiefly to the Schools, and hardly allow of being handed on to the public.

In the kingdom of ends everything has either a price or a dignity. Whatever has a price can be replaced by something else as its equivalent; on the other hand, whatever is above all price, and therefore admits of no equivalent, has a dignity. But that which constitutes the condition under which alone something can be an end in itself does not have mere relative worth, i.e., price, but an intrinsic worth, i.e., a dignity.

In law a man is guilty when he violates the rights of others. In ethics he is guilty if he only thinks of doing so.

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.

The possession of power inevitably spoils the free use of reason.