One should as a rule respect public opinion in so far as is necessary to avoid starvation and to keep out of prison, but anything that goes beyond this is voluntary submission to an unnecessary tyranny.

One of the painful things about our time is that those who feel certainty are stupid, and those with any imagination and understanding are filled with doubt and indecision.

There are two ways of avoiding fear: one is by persuading ourselves that we are immune from disaster, and the other is by the practice of sheer courage. The latter is difficult, and to everybody becomes impossible at a certain point. The former has therefore always been more popular. Primitive magic has the purpose of securing safety, either by injuring enemies, or by protecting oneself by talismans, spells, or incantations.

One must care about a world one will not see.

I like mathematics because it is not human and has nothing particular to do with this planet or with the whole accidental universe - because, like Spinoza's God, it won't love us in return.

Our instinctive emotions are those that we have inherited from a much more dangerous world, and contain, therefore, a larger portion of fear than they should.

The Ten Commandments should be headed like an examination paper: No more than six to be attempted.