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Page:Popular Science Monthly Volume 57.djvu/217

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statesman unless he lives at least a sufficient number of years to acquire the development of an adult, and to have the opportunity of developing his abilities and distinguishing himself. If great men were great from their infancy, and if we had the means of as certaining this fact, then, and only then, would the method used be correct.

It is ordinarily stated that the average duration of life is somewhere between thirty-three and forty years, and Mr. Thayer considers that in the present century it has moved forward towards the latter figure. What this means is that if we were to keep a record of the age at death of all Americans who are to be born within the first ten years of the coming century, we should find that their average age at death would be some thirty odd years. But this number can by no means be used as a standard with which to compare the average age at death of men of distinction, or indeed of any other class of men selected according to a standard which involves on their part the attainment of mature years. If we were investigating the longevity of twins, or of persons with supernumerary toes, or indeed of persons possessing any quality which one could detect in new-born infants, and if we could determine the average life-period of this class of persons and find that it markedly exceeded the average of the entire community, we should be entitled to conclude that twins, or persons who have supernumerary toes, are blessed with a greater longevity than the average man. But so long as men who are to acquire distinction bear no traces upon them of this power until they exhibit their powers and actually gain distinction, it is obvious that we are concerned with their longevity only from that moment when they have entered, or have become promising candidates for that class of selected individuals whose longevity we are investigating. Proceeding on this basis, I tried to determine the age at which, on the average, men of genius had accomplished a work sufficient to entitle them to be so denominated. This investigation was instigated by Mr. C. S. Peirce, then in charge of courses in logic at the Johns Hopkins University. Under his leadership a small company, of whom I was one, proposed to study certain traits of great men, and for this purpose we tried to select the three hundred greatest' men of all times. The work was never carried on to completion, so that the final selection of the names, and particularly their use in the present connection, must rest on my sole responsibility. I mention these facts mainly to indicate the general representative character of the list which I used. I take from my previously published article the following essential facts: Omitting all doubtful names, about two hundred and fifty names remain, presenting a list which most persons would agree to be fairly representative of the greatest men of all times. Of these again I selected at random those about whom it was easiest to fix the age at which they had done work which would entitle them to a place on this list, or work which almost inevitably led to such distinction. It is a date about midway between the first important work and the greatest work. The average of over sixty such ages is thirty-seven years; which means that, on the average, a man must be thirty-seven years old in order to be a candidate for a place on this list. The real question, then, is, How does the longevity of this select class of thirty-seven-year-old men compare with that of more ordinary individuals? The answer is given by the expectation of life at thirty-seven years, which is twenty-nine years, making the average age at death sixty-six years. And this is precisely the age at death of these sixty great men; showing that, as a class (for these sixty may be considered a fair sample) great men are not distinguished by longevity from other men."

It will thus be seen that my own conclusion is entirely opposed to that I of Mr. Thayer. But this opposition