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

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

A conceptual scheme is never discarded merely because of a few stubborn facts with which it cannot be reconciled; a conceptual scheme is either modified or replaced by a better one, never abandoned with nothing left to take its place.

... scientific research is compounded of ... empirical procedures, general speculative ideas, and mathematical or abstract reasoning.

Just like a turtle, we only make progress if we stick our neck out.

Science is a dynamic undertaking directed to lowering the degree of the empiricism involved in solving problems; or, if you prefer, science is a process of fabricating a web of interconnected concepts and conceptual schemes arising from experiments and observations and fruitful of further experiments and observations.

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.