Injustice, poverty, slavery, ignorance - these may be cured by reform or revolution. But men do not live only by fighting evils. They live by positive goals, individual and collective, a vast variety of them, seldom predictable, at times incompatible.

Science cannot destroy the consciousness of freedom, without which there is no morality and no art, but it can refute it.

Utopias have their value -- nothing so wonderfully expands the imaginative horizons of human potentialities -- but as guides to conduct they can prove literally fatal.

No perfect solution is, not merely in practice, but in principle, possible in human affairs, and any determined attempt to produce it is likely to lead to suffering, disillusionment and failure.

When one is engaged in a desperate defense of one's world and its values, nothing can be given away, any breach in the walls might be fatal, every point must be defended to the death.

Injustice, poverty, slavery, ignorance - these may be cured by reform or revolution. But men do not live only by fighting evils. They live by positive goals, individual and collective, a vast variety of them, seldom predictable, at times incompatible.

Liberty is liberty, not equality or fairness or justice or human happiness or a quiet conscience.