Even philosophers will praise war as ennobling mankind, forgetting the Greek who said: 'War is bad in that it begets more evil than it kills.'

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

Life is the faculty of spontaneous activity, the awareness that we have powers.

We can judge the heart of a man by his treatment of animals.

Thrift is care and scruple in the spending of one's means. It is not a virtue and it requires neither skill nor talent.

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

Philosophy stands in need of a science which shall determine the possibility, principles, and extent of human knowledge à priori.