All thought must, directly or indirectly, by way of certain characters, relate ultimately to intuitions, and therefore, with us, to sensibility, because in no other way can an object be given to us.

That Logic has advanced in this sure course, even from the earliest times, is apparent from the fact that, since Aristotle, it has been unable to advance a step, and thus to all appearance has reached its completion.

To be is to do.

Always recognize that human individuals are ends, and do not use them as means to your end.

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.

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