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.

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.

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.

Behold the turtle. He makes progress only when he sticks his neck out.

Some of mankind's most terrible misdeeds have been committed under the spell of certain magic words or phrases.

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.