JUDGMENT

The combining of imagination and work, i. e., intellectual activity joined to bodily activity, does not entirely suffice for the making of a great man. Excellent examples are inventors, who almost without exception are possessed of active minds and an equal ardor for work, and yet few of them become great. In fact, many of them have difficulty in making both ends meet, and they remain mediocrities. The two qualities can only be used efficiently if joined with a third; namely, common sense. This latter, if developed to its highest degree, becomes what Pascal has called the sense of finesse. Bodily and mental activity are certainly powerful instruments, but like all aids they must be used judiciously. Common sense should guide the choice of problems to be studied.

One of the most potent reasons for the success of great men is that they were wise enough to apply their efforts to worth-while problems. Why will the names of Lavoisier, Sadi-Carnot, Ampere, Fresnel, Saint Claire Deville, Berthelot always be famous? It is because of the greatness of the topics they studied. The results of their discoveries in chemistry, thermo-dynamics, electrodynamics, physical optics, chemical mechanics, organic synthesis have echoed again and again, and the reverberations are daily multiplied.

Many years ago Taine said that the systematic study of the dominant features of his subject was the essential characteristic of the work of a true artist. The same holds true in all realms of human activity. There are dominant phenomena whose influence is felt under most manifold circumstances. A knowledge of these favoring factors is of inestimable value to the human race, and their discoveries merit suitable recognition on the part of their fellowmen.

A second form of judgment is “critical sense,” indispensable to both scholars and to those directing industries. This gift makes possible the detection of errors in measurements or leads to a premonition against erroneous interpretations of observations. It is often lacking in inventors, who are prone to persist in their notions despite self-evident failures. Lesser intellectual lights also cannot bring themselves to abandon favorite hypotheses which are not in agreement with the facts; they seek refuge in new additional hypotheses and cling fast to the original notion. Ditte, a pupil of Saint Claire Deville, furnished a striking example of this type of mental gymnastics. While trying to extend the law of fixed dissociation tensions to the decomposition of solutions of mercuric sulphate, he found that the concentration of the liquid with respect to sulphuric acid increased with increasing concentration of mercuric sulphate. Instead of abandoning his hypothesis, which was obviously inaccurate, he introduced a second, which today appears absurd, but for a time it enjoyed a certain credence among chemists. He postulated that the dissolved mercuric sulphate was present in two forms, part as neutral salt and part as basic salt, dissolved in, but not combined with, sulphuric acid. He calculated the proportion of the basic salt supposedly thus dissolved which would leave a constant concentration of sulphuric acid in solution, and he viewed the results of this arbitrary calculation as experimental verification of his hypothesis. This species of error is constantly perpetrated nowadays by those who speculate as to the constitution of matter. Savants who, like Lavoisier, Claud Bernard, Pasteur, combine an ever-watchful imagination with a critical sense severe enough to lead them to discard hypotheses found contrary to fact are extremely rare.

Finally, there is a still more refined form of common sense, namely, the sense of subtle discrimination which enables us to guide our minds directly into domains of thought which are not perfectly obvious. It is often asserted that hypotheses are free to all, an investigator may postulate what he pleases, provided he finally subjects his notions to precise, experimental test. However, it is distinctly worth-while not to set up too many inexact hypotheses, for time should be economized to the end that production may be increased. A certain instinctive discernment is necessary to set one rapidly on the best line of procedure. Rules for this cannot be laid down; it is a matter of feeling and not of reason. The remarkable productivity of Pasteur was doubtless due to his ability, from the very first, to thoroughly organize his researches. Sometimes this ability is ascribed to chance, but this is not correct, for we see here the fruit of a very shrewd form of common sense. Saint Claire Deville’s thought that there might be a possible analogy between the phenomena of decomposition and those of vaporization was an intuition of genius; it led him to the discovery of chemical equilibrium, which he termed dissociation, and a new science, chemical mechanics, has been erected on this idea.

Good common sense is often a gift of nature, but the more delicate sense of subtle discrimination is principally a result of education. It is very rarely observed among the children of the lower grades; it is a product of classical education, and, above all, it springs from that which is taught in the home. The English declare that thirty-six years of education are necessary to make a gentleman, twelve for the grandfather, twelve for the father and twelve for the son. The same holds true for this sense of finesse. Pascal, Lavoisier, scholars of the first rank, came from families of long-standing culture, and their successes were due in large measure to the prolonged efforts of their ancestors.

The study of classics and humanities aids in developing this trait. Literary or historical criticism requires a constant evaluation of opposing points of view to determine the part played by each in domains not amenable to exact measurement. On the other hand, the study of science develops the geometrical viewpoint, i. e., the use of syllogism, which is utterly useless when comparing phenomena possessing no common measure or such as are based on mere probabilities. The exclusive use of rigorous reasoning and an absolute faith in his conclusions are sometimes very dangerous to a savant. They hinder him from taking account of the real value of the hypotheses which he has made and from recognizing the possible errors in his experiments. These modes of thought are not less hazardous to the industrialist to whom they may impart an unwarranted confidence in the predictions as to the advantages of a new business venture or of a new method of manufacture.