know that there are to the best of our present knowledge twelve men more eminent than Homer and fifty-six men more eminent than Virgil. Further by reckoning the probable errors it is found that the chances are even that Homer's place on the list is between 10 and 26 and Virgil's between 42 and 98.
But while our general knowledge apart from any such list as this may suffice to compare Homer with Virgil as accurately as is needful, this does not hold for men whose work is not readily comparable. Is Raphael, Descartes or Columbus the more eminent? As a matter of fact they stand respectively 2 2d, 23d and 24th on the list, and are equally eminent. I do not see how this result could have been reached from any general knowledge we may have of the work and fame of these men. Or again, Newton follows Homer and Hume follows Virgil on the list, consequently Newton is as much more eminent than Hume as Homer is than Virgil.
Things can be arranged in order more easily than they can be measured. We know that one sound is louder than another, though we may be unable to say whether it is more or less than twice as loud. We can arrange without much difficulty the examination papers of our students in the order of excellence, though unable to decide that one paper is twice as good as another. But the theory of probability makes even the measurement of the eminence of great men possible.
If all the men of the races and ages with which we are concerned were arranged in order, we might divide them into quarters. Supposing there to be one hundred million individuals in all from whom these men might have arisen, taking the adult male population of the countries and periods producing nearly all of them, we should have at the end the 25 million least deserving of credit, including the defective and delinquent classes. Then we should have two groups each containing 25 million, one falling below and one rising above the average. These are the ordinary men who depart from the median by an amount less than the probable error. Then at the upper end we have the group of 25 million individuals who through some special trait or through a combination of traits rise above the others. At the extreme end of this group are the thousand preeminent men of our list.
What a man is and does is the result of innumerable influences, chiefly small and independent, some pulling him down and some lifting him up. In so far as this is the case, the men will be grouped together and depart from each other in a certain definite fashion. The matter can most readily be illustrated by taking a single trait such as height. If these men were placed in a row arranged according to height, the tops of their heads would form a curve of which an exaggerated form is given. In a general way the middle man would be of the average height,
