As in the experimental sciences, truth cannot be distinguished from error as long as firm principles have not been established through the rigorous observation of facts.

Where observation is concerned, chance favors only the prepared mind.

It is not the germs we need worry about. It is our inner terrain.

In good philosophy, the word cause ought to be reserved to the single Divine impulse that has formed the universe.

There is no such thing as applied science, only the application of pure science.

There is a time in every man's life when he looks to his God, when he looks at his life, when he wonders how he will be remembered.

Science knows no country, because knowledge belongs to humanity, and is the torch which illuminates the world.