“While I thought I have been learning how to live, I have been learning how to die.”

“Truth was the only daughter of Time.”

“Obstacles cannot crush me. Every obstacle yields to stern resolve. He who is fixed to a star does not change his mind.”

“The greatest deception men suffer is from their own opinions.”

“The water you touch in a river is the last of that which has passed, and the first of that which is coming. Thus it is with time present.”

“The acquisition of any knowledge is always of use to the intellect, because it may thus drive out useless things and retain the good. For nothing can be loved or hated unless it is first known.”

“Geometry was invented that we might expeditiously avoid, by drawing Lines, the Tediousness of Computation.”

“I have not been able to discover the cause of those properties of gravity from phenomena, and I frame no hypotheses; for whatever is not deduced from the phenomena is to be called a hypothesis, and hypotheses, whether metaphysical or physical, whether of occult qualities or mechanical, have no place in experimental philosophy.”

“There is a fundamental difference between religion, which is based on authority and science, which is based on observation and reason. Science will win, because it works.”

“My goal is simple. It is a complete understanding of the universe, why it is as it is and why it exists at all.”

“See now the power of truth; the same experiment which at first glance seemed to show one thing, when more carefully examined, assures us of the contrary.”

“In the natural sciences, whose conclusions are true and necessary and have nothing to do with human will, one must take care not to place oneself in the defense of error; for here a thousand Demostheneses and a thousand Aristotles would be left in the lurch by every mediocre wit who happened to hit upon the truth for himself.”