[When asked "Dr. Einstein, why is it that when the mind of man has stretched so far as to discover the structure of the atom we have been unable to devise the political means to keep the atom from destroying us?"] That is simple, my friend. It is because politics is more difficult than physics.
Many a young lady does not realize just how strong her love for a young man is until he fails to pass the approval test with her parents. There is no fear in love; but perfect love casteth out fear. Of all forms of caution, caution in love is the most fatal. There are only two truly infinite things, the universe and stupidity. And I am unsure about the universe.
Weakness of attitude becomes weakness of character; it becomes lack of power to act with courage proportionate to danger. All this must lead to the destruction of our intellectual life unless the danger summons up strong personalities able to fill the lukewarm and discouraged with new strength and resolution.
Out of the multitude of our sense experiences we take, mentally and arbitrarily, certain repeatedly occurring complexes of sense impression (partly in conjunction with sense impressions which are interpreted as signs for sense experiences of others), and we attribute to them a meaning the meaning of the bodily object.
On the left-hand side of the field equation we may add the fundamental tensor guv, multiplied by a universal constant, -λ, at present unknown, without destroying the general covariance.
It's not that life has been easy, perfect or exactly as expected. I just choose to be happy and grateful no matter how it all turns out. If people are good only because they fear punishment, and hope for reward, then we are a sorry lot indeed.
A permanent peace cannot be prepared by threats but only by the honest attempt to create a mutual trust. However strong national armaments may be, they do not create military security for any nation nor do they guarantee the maintenance of peace.