The test of all knowledge is experiment. Experiment is the sole judge of scientific truth.

Philosophy of science is about as useful to scientists as ornithology is to birds.

Our freedom to doubt was born out of a struggle against authority in the early days of science. It was a very deep and strong struggle: permit us to question - to doubt - to not be sure. I think that it is important that we do not forget this struggle and thus perhaps lose what we have gained.

From a long view of the history of mankind the most significant event of the nineteenth century will be judged as Maxwell's discovery of the laws of electrodynamics.

Nature does not care what we call it, she just keeps on doing it.

If there is something very slightly wrong in our definition of the theories, then the full mathematical rigor may convert these errors into ridiculous conclusions.

Know how to solve every problem that has been solved.