Whether a man lives or dies in vain can be measured only by the way he faces his own problems, by the success or failure of the inner conflict within his own soul. And of this no one may know save God.

Even the development of the steam engine owed but little to the advancement of science.

Science emerges from the other progressive activities of man to the extent that new concepts arise from experiments and observations, and that the new concepts in turn lead to further experiments and observations.

Therefore, a grotesque account of a period some thousands of years ago is taken seriously though it be built by piling special assumptions on special assumptions, ad hoc hypothesis [invented for a purpose] on ad hoc hypothesis, and tearing apart the fabric of science whenever it appears convenient. The result is a fantasia which is neither history nor science.

In every section of the entire area where the word science may properly be applied, the limiting factor is a human one. We shall have rapid or slow advance in this direction or in that depending on the number of really first-class men who are engaged in the work in question. ... So in the last analysis, the future of science in this country will be determined by our basic educational policy.

The stumbling way in which even the ablest of the scientists in every generation have had to fight through thickets of erroneous observations, misleading generalizations, inadequate formulation, and unconscious prejudice is rarely appreciated by those who obtain their scientific knowledge from textbooks.

I venture to define science as a series of interconnected concepts and conceptual schemes arising from experiment and observation and fruitful of further experiments and observations. The test of a scientific theory is, I suggest, its fruitfulness.