primitive stove. The flesh of the quarry, wrapped with water in its
skin, was boiled by contact with heated stones. Cooking by stones was
also done in wooden vessels. Hollow gourds were protected from the fire
by coats of clay. Thus, from the burned clay accidentally originated the
enveloping pot, which rendered the gourd superfluous, although for a
long time thereafter the clay was still spread over the gourd, or
pressed into woven wicker-work before the potter's art assumed its final
independence. Even then the wicker-work ornament was retained, as a sort
of attest of its origin.
We see, thus, it is by accidental circumstances, or by such as lie
without our purpose, foresight, and power, that man is gradually led to
the acquaintance of improved means of satisfying his wants. Let the
reader picture to himself the genius of a man who could have foreseen
without the help of accident that clay handled in the ordinary manner
would produce a useful cooking utensil! The majority of the inventions
made in the early stages of civilisation, including language, writing,
money, and the rest, could not have been the product of deliberate
methodical reflexion for the simple reason that no idea of their value
and significance could have been had except from practical use. The
invention of the bridge may have been suggested by the trunk of a tree
which had fallen athwart a mountain-torrent; that of the tool by the use
of a stone accidentally taken into the hand to crack nuts. The use of
fire probably started in and was disseminated from regions where
volcanic eruptions, hot springs, and burning jets of natural gas
afforded opportunity for quietly observing and turning to practical
account the properties of fire. Only after that had been done could the
significance of the fire-drill be appreciated, an instrument which was
probably discovered from boring a hole through a piece of wood. The
suggestion of a distinguished inquirer that the invention of the
fire-drill originated on the occasion of a religious ceremony is both
fantastic and incredible. And as to the use of fire, we should no more
attempt to derive that from the invention of the fire-drill than we
should from the invention of sulphur matches. Unquestionably the
opposite course was the real one.[84]
Similar phenomena, though still largely veiled in obscurity, mark the
initial transition of nations from a hunting to a nomadic life and to
agriculture.[85] We shall not multiply examples, but content ourselves
with the remark that the same phenomena recur in historical times, in
the ages of great technical inventions, and, further, that regarding
them the most whimsical notions have been circulated--notions which
ascribe to accident an unduly exaggerated part, and one which in a
psychological respect is absolutely impossible. The observation of steam
escaping from a tea-kettle and of the clattering of the lid is supposed
to have led to the invention of the steam-engine. Just think of the gap
between this spectacle and the conception of the performance of great
mechanical work by steam, for a man totally ignorant of the
steam-engine! Let us suppose, however, that an engineer, versed in the
practical construction of pumps, should accidentally dip into water an
inverted bottle that had been filled with steam for drying and still
retained its steam. He would see the water rush violently into the
bottle, and the idea would very naturally suggest itself of founding on
this experience a convenient and useful atmospheric steam-pump, which by
imperceptible degrees, both psychologically possible and immediate,
would then undergo a natural and gradual transformation into Watt's
steam-engine.
But granting that the most important inventions are brought to man's
notice accidentally and in ways that are beyond his foresight, yet it
does not follow that accident alone is sufficient to produce an
invention. The part which man plays is by no means a passive one. Even
the first potter in the primeval forest must have felt some stirrings of
genius within him. In all such cases, the inventor is obliged _to take
note_ of the new fact, he must discover and grasp its advantageous
feature, and must have the power to turn that feature to account in the
realisation of his purpose. He must _isolate_ the new feature, impress
it upon his memory, unite and interweave it with the rest of his
thought; in short, he must possess the capacity _to profit by
experience_.
The capacity to profit by experience might well be set up as a test of
intelligence. This power varies considerably in men of the same race,
and increases enormously as we advance from the lower animals to man.
The former are limited in this regard almost entirely to the reflex
actions which they have inherited with their organism, they are almost
totally incapable of individual experience, and considering their simple
wants are scarcely in need of it. The ivory-snail (_Eburna spirata_)
never learns to avoid the carnivorous Actinia, no matter how often it
may wince under the latter's shower of needles, apparently having no
memory for pain whatever.[86] A spider can be lured forth repeatedly
from its hole by touching its web with a tuning-fork. The moth plunges
again and again into the flame which has burnt it. The humming-bird
hawk-moth[87] dashes repeatedly against the painted roses of the
wall-paper, like the unhappy and desperate thinker who never wearies of
attacking the same insoluble chimerical problem. As aimlessly almost as
Maxwell's gaseous molecules and in the same unreasoning manner common
flies in their search for light and air stream against the glass pane of
a half-opened window and remain there from sheer inability to find their
way around the narrow frame. But a pike separated from the minnows of
his aquarium by a glass partition, learns after the lapse of a few
months, though only after having butted himself half to death, that he
cannot attack these fishes with impunity. What is more, he leaves them
in peace even after the removal of the partition, though he will bolt a
strange fish at once. Considerable memory must be attributed to birds of
passage, a memory which, probably owing to the absence of disturbing
thoughts, acts with the precision of that of some idiots. Finally, the
susceptibility to training evinced by the higher vertebrates is
indisputable proof of the ability of these animals to profit by
experience.
A powerfully developed _mechanical_ memory, which recalls vividly and
faithfully old situations, is sufficient for avoiding definite
particular dangers, or for taking advantage of definite particular
opportunities. But more is required for the development of _inventions_.
More extensive chains of images are necessary here, the excitation by
mutual contact of widely different trains of ideas, a more powerful,
more manifold, and richer connexion of the contents of memory, a more
powerful and impressionable psychical life, heightened by use. A man
stands on the bank of a mountain-torrent, which is a serious obstacle to
him. He remembers that he has crossed just such a torrent before on the
trunk of a fallen tree. Hard by trees are growing. He has often moved
the trunks of fallen trees. He has also felled trees before, and then
moved them. To fell trees he has used sharp stones. He goes in search of
such a stone, and as the old situations that crowd into his memory and
are held there in living reality by the definite powerful interest which
he has in crossing just this torrent,--as these impressions are made to
pass before his mind in the _inverse order_ in which they were here
evoked, he invents the bridge.
There can be no doubt but the higher vertebrates adapt their actions in
some moderate degree to circumstances. The fact that they give no
appreciable evidence of advance by the accumulation of inventions, is
satisfactorily explained by a difference of degree or intensity of
intelligence as compared with man; the assumption of a difference of
kind is not necessary. A person who saves a little every day, be it ever
so little, has an incalculable advantage over him who daily squanders
that amount, or is unable to keep what he has accumulated. A slight
quantitative difference in such things explains enormous differences of
advancement.
The rules which hold good in prehistoric times also hold good in
historical times, and the remarks made on invention may be applied
almost without modification to discovery; for the two are distinguished
solely by the use to which the new knowledge is put. In both cases the
investigator is concerned with some _newly observed_ relation of new or
old properties, abstract or concrete. It is observed, for example, that
a substance which gives a chemical reaction _A_ is also the cause of a
chemical reaction _B_. If this observation fulfils no purpose but that
of furthering the scientist's insight, or of removing a source of
intellectual discomfort, we have a discovery; but an invention, if in
using the substance giving the reaction _A_ to produce the desired
reaction _B_, we have a practical end in view, and seek to remove a
source of material discomfort. The phrase, _disclosure of the connexion
of reactions_, is broad enough to cover discoveries and inventions in
all departments. It embraces the Pythagorean proposition, which is a
combination of a geometrical and an arithmetical reaction, Newton's
discovery of the connexion of Kepler's motions with the law of the
inverse squares, as perfectly as it does the detection of some minute
but appropriate alteration in the construction of a tool, or of some
appropriate change in the methods of a dyeing establishment.
The disclosure of new provinces of facts before unknown can only be
brought about by accidental circumstances, under which are _remarked_
facts that commonly go unnoticed. The achievement of the discoverer here
consists in his _sharpened attention_, which detects the uncommon
features of an occurrence and their determining conditions from their
most evanescent marks,[88] and discovers means of submitting them to
exact and full observation. Under this head belong the first disclosures
of electrical and magnetic phenomena, Grimaldi's observation of
interference, Arago's discovery of the increased check suffered by a
magnetic needle vibrating in a copper envelope as compared with that
observed in a bandbox, Foucault's observation of the stability of the
plane of vibration of a rod accidentally struck while rotating in a
turning-lathe, Mayer's observation of the increased redness of venous
blood in the tropics, Kirchhoff's observation of the augmentation of the
_D_-line in the solar spectrum by the interposition of a sodium lamp,
Schönbein's discovery of ozone from the phosphoric smell emitted on the
disruption of air by electric sparks, and a host of others. All these
facts, of which unquestionably many were _seen_ numbers of times before
they were _noticed_, are examples of the inauguration of momentous
discoveries by accidental circumstances, and place the importance of
strained attention in a brilliant light.
But not only is a significant part played in the beginning of an inquiry
by co-operative circumstances beyond the foresight of the investigator;
their influence is also active in its prosecution. Dufay, thus, whilst
following up the behavior of _one_ electrical state which he had
assumed, discovers the existence of _two_. Fresnel learns by accident
that the interference-bands received on ground glass are seen to better
advantage in the open air. The diffraction-phenomenon of two slits
proved to be considerably different from what Fraunhofer had
anticipated, and in following up this circumstance he was led to the
important discovery of grating-spectra. Faraday's induction-phenomenon
departed widely from the initial conception which occasioned his
experiments, and it is precisely this deviation that constitutes his
real discovery.
Every man has pondered on some subject. Every one of us can multiply the
examples cited, by less illustrious ones from his own experience. I
shall cite but one. On rounding a railway curve once, I accidentally
remarked a striking apparent inclination of the houses and trees. I
inferred that the direction of the total resultant _physical_
acceleration of the body reacts _physiologically_ as the vertical.
Afterwards, in attempting to inquire more carefully into this
phenomenon, and this only, in a large whirling machine, the collateral
phenomena conducted me to the sensation of angular acceleration,
vertigo, Flouren's experiments on the section of the semi-circular
canals etc., from which gradually resulted views relating to sensations
of direction which are also held by Breuer and Brown, which were at
first contested on all hands, but are now regarded on many sides as
correct, and which have been recently enriched by the interesting
inquiries of Breuer concerning the _macula acustica_, and Kreidel's
experiments with magnetically orientable crustacea.[89] Not disregard of
accident but a direct and purposeful employment of it advances research.
The more powerful the psychical connexion of the memory pictures
is,--and it varies with the individual and the mood,--the more apt is
the same accidental observation to be productive of results. Galileo
knows that the air has weight; he also knows of the "resistance to a
vacuum," expressed both in weight and in the height of a column of
water. But the two ideas dwelt asunder in his mind. It remained for
Torricelli to vary the specific gravity of the liquid measuring the
pressure, and not till then was the air included in the list of
pressure-exerting fluids. The reversal of the lines of the spectrum was
seen repeatedly before Kirchhoff, and had been mechanically explained.
But it was left for his penetrating vision to discern the evidence of
the connexion of this phenomenon with questions of heat, and to him
alone through persistent labor was revealed the sweeping significance of
the fact for the mobile equilibrium of heat. Supposing, then, that such
a rich organic connexion of the elements of memory exists, and is the
prime distinguishing mark of the inquirer, next in importance certainly
is that _intense interest_ in a definite object, in a definite idea,
which fashions advantageous combinations of thought from elements before
disconnected, and obtrudes that idea into every observation made, and
into every thought formed, making it enter into relationship with all
things. Thus Bradley, deeply engrossed with the subject of aberration,
is led to its solution by an exceedingly unobtrusive experience in
crossing the Thames. It is permissible, therefore, to ask whether
accident leads the discoverer, or the discoverer accident, to a
successful outcome in scientific quests.
No man should dream of solving a great problem unless he is so
thoroughly saturated with his subject that everything else sinks into
comparative insignificance. During a hurried meeting with Mayer in
Heidelberg once, Jolly remarked, with a rather dubious implication, that
if Mayer's theory were correct water could be warmed by shaking. Mayer
went away without a word of reply. Several weeks later, and now
unrecognised by Jolly, he rushed into the latter's presence exclaiming:
"Es ischt aso!" (It is so, it is so!) It was only after considerable
explanation that Jolly found out what Mayer wanted to say. The incident
needs no comment.[90]
A person deadened to sensory impressions and given up solely to the
pursuit of his own thoughts, may also light on an idea that will divert
his mental activity into totally new channels. In such cases it is a
psychical accident, an intellectual experience, as distinguished from a
physical accident, to which the person owes his discovery--a discovery
which is here made "deductively" by means of mental copies of the world,
instead of experimentally. _Purely_ experimental inquiry, moreover, does
not exist, for, as Gauss says, virtually we always experiment with our
thoughts. And it is precisely that constant, corrective interchange or
intimate union of experiment and deduction, as it was cultivated by
Galileo in his _Dialogues_ and by Newton in his _Optics_, that is the
foundation of the benign fruitfulness of modern scientific inquiry as
contrasted with that of antiquity, where observation and reflexion
ofttimes pursued their respective courses like two strangers.
We have to wait for the appearance of a favorable physical accident. The
movement of our thoughts obeys the law of association. In the case of
meagre experience the result of this law is simply the mechanical
reproduction of definite sensory experiences. On the other hand, if the
psychical life is subjected to the incessant influences of a powerful
and rich experience, then every representative element in the mind is
connected with so many others that the actual and natural course of the
thoughts is easily influenced and determined by insignificant
circumstances, which accidentally are decisive. Hereupon, the process
termed imagination produces its protean and infinitely diversified
forms. Now what can we do to guide this process, seeing that the
combinatory law of the images is without our reach? Rather let us ask,
what influence can a powerful and constantly recurring idea exert on the
movement of our thoughts? According to what has preceded, the answer is
involved in the question itself. The _idea_ dominates the thought of the
inquirer, not the latter the former.
Let us see, now, if we can acquire a profounder insight into the process
of discovery. The condition of the discoverer is, as James has aptly
remarked, not unlike the situation of a person who is trying to remember
something that he has forgotten. Both are sensible of a gap, and have
only a remote presentiment of what is missing. Suppose I meet in a
company a well-known and affable gentleman whose name I have forgotten,
and who to my horror asks to be introduced to some one. I set to work
according to Lichtenberg's rule, and run down the alphabet in search of
the initial letter of his name. A vague sympathy holds me at the letter
_G_. Tentatively I add the second letter and am arrested at _e_, and
long before I have tried the third letter _r_, the name "Gerson" sounds
sonorously upon my ear, and my anguish is gone. While taking a walk I
meet a gentleman from whom I receive a communication. On returning home,
and in attending to weightier affairs, the matter slips my mind.
Moodily, but in vain, I ransack my memory. Finally I observe that I am
going over my walk again in thought. On the street corner in question
the self-same gentleman stands before me and repeats his communication.
In this process are successively recalled to consciousness all the
percepts which were connected with the percept that was lost, and with
them, finally, that, too, is brought to light. In the first case--where
the experience had already been made and is permanently impressed on our
thought--a _systematic_ procedure is both possible and easy, for we know
that a name must be composed of a limited number of sounds. But at the
same time it should be observed that the labor involved in such a
combinatorial task would be enormous if the name were long and the
responsiveness of the mind weaker.
It is often said, and not wholly without justification, that the
scientist has solved a _riddle_. Every problem in geometry may be
clothed in the garb of a _riddle_. Thus: "What thing is that _M_ which
has the properties _A_, _B_, _C_?" "What circle is that which touches
the straight lines _A_, _B_, but touches _B_ in the point _C_?" The
first two conditions marshal before the imagination the group of circles
whose centres lie in the line of symmetry of _A_, _B_. The third
condition reminds us of all the circles having centres in the straight
line that stands at right angles to _B_ in _C_. The _common_ term, or
common terms, of the two groups of images solves the riddle--satisfies
the problem. Puzzles dealing with things or words induce similar
processes, but the memory in such cases is exerted in many directions
and more varied and less clearly ordered provinces of ideas are
surveyed. The difference between the situation of a geometer who has a
construction to make, and that of an engineer, or a scientist,
confronted with a problem, is simply this, that the first moves in a
field with which he is thoroughly acquainted, whereas the two latter are
obliged to familiarise themselves with this field subsequently, and in a
measure far transcending what is commonly required. In this process the
mechanical engineer has at least always a definite goal before him and
definite means to accomplish his aim, whilst in the case of the
scientist that aim is in many instances presented only in vague and
general outlines. Often the very formulation of the riddle devolves on
him. Frequently it is not until the aim has been reached that the
broader outlook requisite for systematic procedure is obtained. By far
the larger portion of his success, therefore, is contingent on luck and
instinct. It is immaterial, so far as its character is concerned,
whether the process in question is brought rapidly to a conclusion in
the brain of one man, or whether it is spun out for centuries in the
minds of a long succession of thinkers. The same relation that a word
solving a riddle bears to that riddle is borne by the modern conception
of light to the facts discovered by Grimaldi, Römer, Huygens, Newton,
Young, Malus, and Fresnel, and only by the help of this slowly developed
conception is our mental vision enabled to embrace the broad domain of
facts in question.
A welcome complement to the discoveries which the history of
civilisation and comparative psychology have furnished, is to be found
in the confessions of great scientists and artists. Scientists _and_
artists, we might say, for Liebig boldly declared there was no essential
difference between the two. Are we to regard Leonardo da Vinci as a
scientist or as an artist? If the artist builds up his work from a few
motives, the scientist discovers the motives which permeate reality. If
scientists like Lagrange or Fourier are in a certain measure artists in
the presentation of their results, on the other hand, artists like
Shakespeare or Ruysdael are scientists in the insight which must have
preceded their creations.