The production of too many useful things results in too many useless people.
Advances in science help to delegitimize the rule of kings and the power of the Church.
Accumulate, accumulate! This is Moses and the Prophets!
The Communists have no need to introduce free love; it has existed almost from time immemorial.
The product of mental labor - science - always stands far below its value, because the labor-time necessary to reproduce it has no relation at all to the labor-time required for its original production.
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).