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.