The morality of work is the morality of slaves, and the modern world has no need of slavery.

Hitler is an outcome of Rousseau.

As soon as it is held that any belief, no matter what, is important for some other reason than that it is true, a whole host of evils is ready to spring up.

In the part of this universe that we know there is great injustice, and often the good suffer, and often the wicked prosper, and one hardly knows which of those is the more annoying.

Freedom in general may be defined as the absence of obstacles to the realization of desires.

The harm that theology has done is not to create cruel impulses, but to give them the sanction of what professes to be lofty ethic, and to confer an apparently sacred character upon practices which have come down from more ignorant and barbarous times.

While the dogmatist is harmful, the sceptic is useless ...; one is certain of knowing, the other of not knowing. What philosophy should dissipate is certainty, whether of knowledge or of ignorance. Knowledge is not so precise a concept as is commonly thought. Instead of saying 'I know this', we ought to say 'I more or less know something more or less like this'. ... Knowledge in practical affairs has not the certainty or the precision of arithmetic.