“For a variety of reasons, perhaps best understood by psychoanalysis, when we talk or write about scientific discovery, we tend to dwell lovingly on great events – Galileo and uniform acceleration, Newton and universal gravitation, Einstein and relativity. We insist that a theory of discovery postulate proceses sufficiently powerful to produce these events. It is right to so insist, but we must not forget how rare such events are, and we must not postulate processes so powerful that they predict discovery of first magnitude as a daily matter.
On the contrary, for each such event there is an investment of thousands of man-years of investigation by hundreds of talented and hard-working scientists. This particular slot machine produces many stiff arms for every jackpot. At the same time that we explain how Schrodinger, in 1926, came to quantum mechanics, we must explain why Planck, Bohr, Einstein, de Broglie, and other men of comparable ability struggled for the preceding twenty years without completing this discovery. Scientific discovery is a rare event; a theory to explain it must predict innumerable failures for every success.”
– Herbert A. Simon
Scientific Discovery and The Psychology of Problem Solving, In Models of Discovery, 1977.