All mathematics is tautology.

Every sign by itself seems dead. What gives it life?--In use it is alive. Is life breathed into it there?--Or is the use its life?

It is an hypothesis that the sun will rise tomorrow: and this means that we do not know whether it will rise.

One often makes a remark and only later sees how true it is.

The common behavior of mankind is the system of reference by means of which we interpret an unknown language.

Death is not an event in life: we do not live to experience death.

Everything that can be said, can be said clearly.