"No amount of experimentation can ever prove me right;
 a single experiment can prove me wrong."
   -- Albert Einstein

"Man is a creative animal, doomed to strive toward a goal,
 engaged in full-time engineering."
   -- Fyodor Dostoevsky

"We have a habit in writing articles published in scientific 
 journals to make the work as finished as possible, to cover 
 up all the tracks, to not worry about the blind alleys or 
 describe how you had the wrong idea at first, and so on.
 So there isn't any place to publish, in a dignified manner, 
 what you actually did in order to get to do the work."
   -- Richard Feynman, 1966 Nobel Lecture

"Mathematics possesses not only truth but supreme beauty;
 a beauty cold and austere, like that of sculpture, without
 appeal to any part of our weaker nature, sublimely pure,
 and capable of a stern perfection which only the greatest
 art can show."
   -- Bertrand Russell

"The sciences do not try to explain, they hardly even try to
 interpret, they mainly make models.  By a model is meant a
 mathematical construct which, with the addition of certain
 verbal interpretations, describes observed phenomena.  The
 justification of such a mathematical construct is solely 
 and precisely that it is expected to work."
   -- John von Neumann

"The important thing is science is not so much to obtain new
 facts as to discover new ways of thinking about them."
   -- Sir William Bragg

"If it can't be expressed in figures, it is not science; it 
 is opinion."
   -- Lazarus Long

"Truth in science can be defined as the working hypothesis best suited to open the way to the next better one." -- Konrad Lorenz

"First you guess. Don't laugh, this is the most important step. Then you compute the consequences. Compare the consequences to experience. If it disagrees with experience, the guess is wrong. In that simple statement is the key to science. It doesn't matter how beautiful your guess is or how smart you are or what your name is. If it disagrees with experience, it's wrong. That's all there is to it." -- Richard Feynman, on how to discover a new law of physics