A useful member of society does not merely work hard and produce much
for his own benefit; he should add to the common fund of knowledge.
In other words, he must produce new ideas, discover scientific laws,
devise new literary or artistic presentations, perfect methods of
government; in short, he must play a creative role.
What is the mechanism by which this progress is realized? Contrary to
popular belief, our knowledge does not increase by leaps and bounds,
but the development is regular and very slow. Each step forward, in
the majority of cases, comes from the simple combination of facts
previously known. It is only necessary to delve in the storehouse of
knowledge and to bring new relations to light. This correlation is a
fruit of the mental faculty, imagination, whose functioning is rather
capricious. The solution of a problem may be sought unsuccessfully for
a long time, and then suddenly it may flash into the mind at a time
when the problem is no longer being consciously considered.
The work of all great men shows the employment of imagination; it
constitutes the beginning of all great discoveries. Pascal created
hydrostatics by connecting the limitation of the height of a
barometric column with the weight of the atmosphere; Newton discovered
universal gravitation by comparing the movement of the planets with the
fall of an apple; Pasteur founded microbiology by connecting the spread
of disease with the life processes of microscopic organisms. Likewise,
in the field of letters, we find writers dealing with ideas common to
all humanity and sending them forth in new attire. La Fontaine gave
life to Aesop’s fables by endowing the animals with speech; Corneille
introduced a sense of duty magnified almost to heroism into the Spanish
dramas. Artists sometimes slightly exaggerate certain features of
their models to produce a more striking representation. Michelangelo
accentuated the muscular development of heroic figures and Raphael the
grace of women.
The same is true in industry. Sir William Siemens applied the
theoretical reasoning of Sadi-Carnot to the heating of hearths, and
the regenerative furnace resulted. He invented neither thermo-dynamics
nor industrial heating, but by uniting these two sets of facts, he
brought about a great advance, which made possible the modern processes
of making steel in open hearths and of glass in tank furnaces. All
inventors possess this mental activity, sometimes to excess. It is
interesting to read Bessemer’s autobiography from this point of view.
We see his mind always in feverish agitation, trying each day to
produce something new, usually without success.
This first type of imagination is meditative. It acts slowly, and to
a certain degree may be governed by the will. There is a second type,
rather more delicate in nature, whose action is sudden and not preceded
by reflection. It is this type which enables us to see at a glance all
the correlations and distant consequences of a chance observation. The
predisposing factors are impressionability and nervous sensibility.
This quality varies greatly from individual to individual, certain
minds respond to the slightest external suggestion, while others feel
nothing, see nothing. In general, great scholars are characterized by
a highly developed aptitude for sensing and using facts presented to
them. The accidental observation that his determinations of the density
of nitrogen were discordant led Lord Rayleigh to the discovery of
argon. Other investigators had been faced with the same phenomenon, but
were not markedly impressed. While attempting to fuse platinum, Saint
Claire Deville was struck by the difference between the calculated
temperature of the oxy-hydrogen flame and the observed melting point
of platinum. This led him to suspect the dissociation of water vapor,
while his collaborators, possessed of the same facts, thought nothing
of them. Similarly, Bessemer was led to his process of producing steel
in a converter by the fortuitous observation of the formation of
malleable steel during an attempt to harden cast iron. Or better still,
Auer von Welsbach discovered the incandescent mantle through a chance
observation of the light emitted on calcination of precipitated thoria.
Numerous analytical chemists had doubtless seen the same thing, but
their attention was not arrested.
Great artists viewing nature, great generals before a battle, great
lawyers before a trial are sensible to instantaneous impressions which
escape the notice of ordinary men. The two types of intellectual
activity seem to be predominantly natural endowments. Some children
have wide-awake minds, others are more dull and remain thus throughout
life.
This quality may, however, be developed by education, and more
attention should be paid to this phase of education, than is usually
the case. Exercises in writing composition, problems in geometry,
afford excellent material from which to build up mental habits
of using accumulated knowledge or of seeking new correlations of
known facts. This type of training is doubtless the most useful
function of secondary education. On the other hand, education cannot
develop the second type of mental activity which is not dependent on
reflection, but which functions instantly in some way not known to us.
Nevertheless, there seems to be some possibility of perfecting this
natural endowment by suitable laboratory exercises.