Because the results are expressed in numbers, it is easy to make the mistake of thinking that the intelligence test is a measure like a foot ruler or a pair of scales. It is, of course, a quite different sort of measure. Intelligence is not an abstraction like length and weight; it is an exceedingly complicated notion - which nobody has yet succeeded in defining.
Men can know more than their ancestors did if they start with a knowledge of what their ancestors had already learned....That is why a society can be progressive only if it conserves its traditions.
When men are brought face to face with their opponents, forced to listen and learn and mend their ideas, they cease to be children and savages and begin to live like civilized men. Then only is freedom a reality, when men may voice their opinions because they must examine their opinions.