We see that, in certain respects at least, the greatest scientists have also been great human beings not great merely because of their brilliance, but in a fuller and deeper sense. Indeed, intelligence alone is a very poor criterion of greatness. There are far too many intelligent idiots in this world, who show a regrettable lack of common sense despite their intelligence. Great scientists demonstrate greatness also in their ability to rise above petty self-preoccupation and reach out toward broader realities. Lesser scientists generally, like lesser human beings everywhere, have not shown even an inclination in this direction.
Motivation is only one test of greatness.
It is their pettiness that makes them lesser. The broader the outlook on life, the less the concern with personal gain. Admittedly, there have been great scientists as well as great people in other fields who, owing to egotism or personal ambition, were less great than they might have been. In their work at least, however, they were able far better than most people to rise above pettiness. Often, indeed, it was their high energy that passed in the minds of little people for egotism.