You cannot prepare for war and peace at the same time.

Nevertheless, it is necessary to remember that a planned economy is not yet socialism. A planned economy as such may be accompanied by the complete enslavement of the individual. The achievement of socialism requires the solution of some extremely difficult socio-political problems: how is it possible, in view of the far-reaching centralisation of political and economic power, to prevent bureaucracy from becoming all-powerful and overweening? How can the rights of the individual be protected and therewith a democratic counterweight to the power of bureaucracy be assured?

The ancients knew something, which we seem to have forgotten.

Science can only ascertain what is, but not what should be, and outside of its domain value judgements of all kinds remain necessary.

People like us, who believe in physics, know that the distinction between past, present, and future is only a stubbornly persistent illusion.

I am a determinist. As such, I do not believe in free will...Practically, I am, nevertheless, compelled to act as if freedom of the will existed. If I wish to live in a civilized community, I must act as if man is a responsible being.

Convictions can best be supported with experience and clear thinking.