A mathematician will recognise Cauchy, Gauss, Jacobi or Helmholtz after reading a few pages, just as musicians recognise, from the first few bars, Mozart, Beethoven or Schubert.

It must be splendid to command millions of people in great national ventures, to lead a hundred thousand to victory in battle. But it seems to me greater still to discover fundamental truths in a very modest room with very modest means - truths that will still be foundations of human knowledge when the memory of these battles is painstakingly preserved only in the archives of the historian.

Bring forward what is true, Write it so that it is clear, Defend it to your last breath!

Available energy is the main object at stake in the struggle for existence and the evolution of the world.

Philosophy gets on my nerves. If we analyze the ultimate ground of everything, then everything finally falls into nothingness. But I have decided to resume my lectures again and look the Hydra of doubt straight into the eye, and it be quite ominous if one values one's life.

Since a given system can never of its own accord go over into another equally probable state but into a more probable one, it is likewise impossible to construct a system of bodies that after traversing various states returns periodically to its original state, that is a perpetual motion machine.

Which is more remarkable fact about America: that millionaires are idealists or idealists become millionaires.