“The right to search for the truth implies also a duty; one must not conceal any part of what one has recognized to be the truth.”

“Numerous are the academic chairs, but rare are wise and noble teachers. Numerous and large are the lecture halls, but far from numerous the young people who genuinely thirst for truth and justice. Numerous are the wares that nature produces by the dozen, but her choice products are few.We all know that, so why complain? Was it not always thus and will it not always thus remain? Certainly, and one must take what nature gives as one finds it. But there is also such a thing as a spirit of the times, an attitude of mind characteristic of a particular generation, which is passed on from individual to individual and gives its distinctive mark to a society. Each of us has to his little bit toward transforming this spirit of the times.”

“Anyone who doesn't take truth seriously in small matters cannot be trusted in large ones either.”

“Truth is what stands the test of experience. ”

“One should not pursue goals that are easily achieved. One must develop an instinct for what one can just barely achieve through one’s greatest efforts.”

“It is humankind's duty to respect all life, not only animals have feelings but even also trees and plants.”

“Ethical axioms are found and tested not very differently from the axioms of science. Truth is what stands the test of experience.”