[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.
Concern for man and his fate must always form the chief interest of all technical endeavors. Never forget this in the midst of your diagrams and equations.
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.
The work on satisfactory formulation of technical patents was a true blessing for me. It compelled me to be many-sided in thought, and also offered important stimulation for thought about physics. Following a practical profession is a blessing for people of my type. Because the academic career puts a young person in a sort of compulsory situation to produce scientific papers in impressive quantity, a temptation to superficiality arises that only strong characters are able to resist.
...the physicist cannot simply surrender to the philosopher the critical contemplation of the theoretical foundations; for, he himself knows best, and feels more surely where the shoe pinches...Physical conceptions are free creations of the human mind, and are not, however it may seem, uniquely determined by the external world.