Although gold and silver are not by nature money, money is by nature gold and silver.

Catch a man a fish, and you can sell it to him. Teach a man to fish, and you ruin a wonderful business opportunity.

There is no royal road to science, and only those who do not dread the fatiguing climb of its steep paths have a chance of gaining its luminous summits. (Preface to the French edition).

The rich will do anything for the poor but get off their backs.

The Communists have no need to introduce free love; it has existed almost from time immemorial.

The bourgeoisie of the whole world, which looks complacently upon the wholesale massacre after the battle, is convulsed by horror at the desecration of brick and mortar.

The weapon of criticism can never replace the criticism of weapons.