The Scientific Imagination
It is quite generally recognized that imagination is indispensable in
all sciences; that without it we could only copy, repeat, imitate; that
it is a stimulus driving us onward and launching us into the unknown. If
there does exist a very widespread prejudice to the contrary--if many
hold that scientific culture throttles imagination--we must look for the
explanation of this view first, in the equivocation, pointed out several
times, that makes the essence of the creative imagination consist of
images, which are here most often replaced by abstractions or extracts
of things--whence it results that the created work does not have the
living forms of religion, of art, or even of mechanical invention; and
then, in the rational requirements regulating the development of the
creative faculty--it may not wander at will. In either case its end is
determined, and in order to exist, i.e., in order to be accepted, the
invention must become subject to preestablished rules.
This variety of imagination being, after the esthetic form, the one
that psychologists have best described, we may therefore be brief. A
complete study of the subject, however, remains yet to be made. Indeed,
we may remark that there is no "scientific imagination" in general, that
its form must vary according to the nature of the science, and that,
consequently, it really resolves itself into a certain number of genera
and even of species. Whence arises the need of monographs, each one of
which should be the work of a competent man.
No one will question that mathematicians have a way of thinking all
their own; but even this is too general. The arithmetician, the
algebraist, and more generally the analyst, in whom invention obtains in
the most abstract form of discontinuous functions--symbols and their
relations--cannot imagine like the geometrician. One may well speak of
the ideal figures of geometry--the empirical origin of which is no
longer anywhere contested--but we cannot escape from representing them
as somehow in space. Does anyone think that Monge, the creator of
descriptive geometry, who by his work has aided builders, architects,
mechanics, stone cutters in their labors, could have the same type of
imagination as the mathematician who has been given up all his life to
the theory of number? Here, then, are at least two well-marked
varieties, to say nothing of mixed forms. The physicist's imagination is
necessarily more concrete; since he is incessantly obliged to refer to
the data of sense or to that totality of visual, tactile, motor,
acoustic, thermic, etc., representations that we term the "properties
of matter." Our eye, says Tyndall, cannot see sound waves contract and
dilate, but we construct them in thought--i.e., by means of visual
images. The same remarks are true of chemists. The founders of the
atomic theory certainly saw atoms, and pictured them in the mind's
eye, and their arrangement in compound bodies. The complexity of the
imagination increases still more in the geologist, the botanist, the
zoologist; it approaches more and more, with its increasing details, to
the level of perception. The physician, in whom science becomes also an
art, has need of visual representations of the exterior and interior,
microscopic and macroscopic, of the various forms of diseased
conditions; auditory representations (auscultation); tactile
representations (touch, reverberation, etc.); and let us also add that
we are not speaking merely of diagnosis of diseases, which is a matter
of reproductive imagination, but of the discovery of a new pathologic
"entity," proven and made certain from the symptoms. Lastly, if we do
not hesitate to give a very broad extension to the term "scientific,"
and apply it also to invention in social matters, we shall see that the
latter is still more exacting, for one must represent to oneself not
only the elements of the past and of the present, but in addition
construct a picture of the future according to probable inductions and
deductions.
It might be objected that the foregoing enumeration proves a great
variety in the content of creative imagination but not in the
imagination itself, and that nothing has proven that, under all these
various aspects, there does not exist a so-called scientific
imagination, that always remains identical. This position is untenable.
For we have seen above that there exists no creative instinct in
general, no one mere indeterminate "creative power," but only wants
that, in certain cases, excite novel combinations of images. The nature
of the separable materials, then, is a factor of the first importance;
it is determining, and indicates to the mind the direction in which it
is turned, and all treason in this regard is paid for by aborted
construction, by painful labor for some petty result. Invention,
separated from what gives it body and soul, is nothing but a pure
abstraction.
The monographs called for above would, then, be a not unneeded work. It
is only from them collectively that the role of the imagination in the
sciences could be completely shown, and we might by abstraction separate
out the characters common to all varieties--the essential marks of this
imaginative type.
Mathematics aside, all the sciences dealing with facts--from astronomy
to sociology--suppose three moments, namely, observation, conjecture,
verification. The first depends on external and internal sense, the
second on the creative imagination, the third on rational operations,
although the imagination is not entirely barred from it. In order to
study its influence on scientific development, we shall study it (a) in
the sciences in process of formation; (b) in the established sciences;
(c) in the processes of verification.
II
It has often been said that the perfection of a science is measured by
the amount of mathematics it requires; we might say, conversely, that
its lack of completeness is measured by the amount of imagination that
it includes. It is a psychological necessity. Where the human mind
cannot explain or prove, there it invents; preferring a semblance of
knowledge to its total absence. Imagination fulfills the function
of a substitute; it furnishes a subjective, conjectural solution in
place of an objective, rational explanation. This substitution has
degrees:
(1) The sway of the imagination is almost complete in the
pseudo-sciences (alchemy, astrology, magic, occultism, etc.), which it
would be more proper to call embryonic sciences, for they were the
beginnings of more exact disciplines and their fancies have not been
without use. In the history of science, this is the golden age of the
creative imagination, corresponding to the myth-making period already
studied.
(2) The semi-sciences, incompletely proved (certain portions of
biology, psychology, sociology, etc.), although they show a regression
of imaginative explanation repulsed by the hitherto absent or
insufficient experimentation, nevertheless abound in hypotheses, that
succeed, contradict, destroy one another. It is a commonplace truism
that does not need to be dwelt on--they furnish ad libitum examples of
what has been rightly termed scientific mythology.
Aside from the quantity of imagination expended, often without great
profit, there is another character to be noted--the nature of the belief
that accompanies imaginative creation. We have already seen repeatedly
that the intensity of the imaginary conception is in direct ratio to the
accompanying belief, or rather, that the two phenomena are really
one--merely the two aspects of one and the same state of consciousness.
But faith--i.e., the adherence of the mind to an undemonstrated
assertion--is here at its maximum.
There are in the sciences hypotheses that are not believed in, that are
preserved for their didactic usefulness, because they furnish a simple
and convenient method of explanation. Thus the "properties of matter"
(heat, electricity, magnetism, etc.), regarded by physicists as distinct
qualities even in the first half of the last century; the "two electric
fluids;" cohesion, affinity, etc., in chemistry--these are some of the
convenient and admitted expressions to which, however, we attach no
explanatory value.
There is also to be mentioned the hypothesis held as an approximation
of reality--this is the truly scientific position. It is accompanied by
a provisional and ever-revocable belief. This is admitted, in principle
at least, by all scientists, and has been put into practice by many of
them.
Lastly, there is the hypothesis regarded as the truth itself--one that
is accompanied by a complete, absolute, belief. But daily observation
and history show us that in the realm of embryonic and ill-proven
sciences this disposition is more flourishing than anywhere else. The
less proof there is, the more we believe. This attitude, however wrong
from the standpoint of the logician, seems to the psychologist natural.
The mind clings tenaciously to the hypothesis because the latter is its
own creation, or, because in adopting it, it seems to the mind that it
should have itself discovered the hypothesis, so much does the latter
harmonize with its inner states. Let us take the hypothesis of
evolution, for example: we need not mention its high philosophical
bearing, and the immense influence that it exerts on almost all forms of
human thought. Nevertheless, it still remains an hypothesis; but for
many it is an indisputable and inviolable dogma, raised far above all
controversy. They accept it with the uncompromising fervor of believers:
a new proof of the underlying connection between imagination and
belief--they increase and decrease pari passu.
III
Should we assign as belonging solely to the imagination every invention
or discovery--in a word, whatever is new--in the well-organized sciences
that form a body of solid, constantly-broadening doctrine? It is a hard
question. That which raises scientific knowledge above popular knowledge
is the use of an experimental method and rigorous reasoning processes;
but, is not induction and deduction going from the known to the unknown?
Without desiring to depreciate the method and its value, it must
nevertheless be admitted that it is preventive, not inventive. It
resembles, says Condillac, the parapets of a bridge, which do not help
the traveler to walk, but keep him from falling over. It is of value
especially as a habit of mind. People have wisely discoursed on the
"methods" of invention. There are none; but for which fact we could
manufacture inventors just as we make mechanics and watchmakers. It is
the imagination that invents, that provides the rational faculties with
their materials, with the position, and even the solution of their
problems. Reasoning is only a means for control and proof; it transforms
the work of the imagination into acceptable, logical results. If one has
not imagined beforehand, the logical method is aimless and useless, for
we cannot reason concerning the completely unknown. Even when a problem
seems to advance towards solution wholly through the reason, the
imagination ceaselessly intervenes in the form of a succession of
groupings, trials, guesses, and possibilities that it proposes. The
function of method is to determine its value, to accept or reject
it.
Let us show by a few examples that conjecture, the work of the combining
imagination, is at the root of the most diverse scientific
inventions.
Every mathematical invention is at first only an hypothesis that must be
demonstrated, i.e., must be brought under previously established
general principles: prior to the decisive moment of rational
verification it is only a thing imagined. "In a conversation concerning
the place of imagination in scientific work," says Liebig, "a great
French mathematician expressed the opinion to me that the greater part
of mathematical truth is acquired not through deduction, but through the
imagination. He might have said 'all the mathematical truths,' without
being wrong." We know that Pascal discovered the thirty-second
proposition of Euclid all by himself. It is true that it has been
concluded, wrongly perhaps, that he had also discovered all the earlier
ones, the order followed by the Greek geometrician not being necessary,
and not excluding other arrangements. However it be, reasoning alone was
not enough for that discovery. "Many people," says Naville, "of whom I
am one, might have thought hard all their lives without finding out the
thirty-two propositions of Euclid." This fact alone shows clearly the
difference between invention and demonstration, imagination and reason.
In the sciences dealing with facts, all the best-established
experimental truths have passed through a conjectural stage. History
permits no doubt on this point. What makes it appear otherwise is the
fact that for centuries there has gradually come to be formed a body of
solid belief, making a whole, stored away in classic treatises from
which we learn from childhood, and in which they seem to be arranged of
themselves. We are not told of the series of checks and failures through
which they have passed. Innumerable are the inventions that
remained for a long time in a state of conjecture, matters of pure
imagination, because various circumstances did not permit them to take
shape, to be demonstrated and verified. Thus, in the thirteenth century,
Roger Bacon had a very clear idea of a construction on rails similar to
our railroads; of optical instruments that would permit, as does the
telescope, to see very far, and to discover the invisible. It is even
claimed that he must have foreseen the phenomena of interferences, the
demonstration of which had to be awaited ten centuries.
On the other hand, there are guesses that have met success without much
delay, but in which the imaginative phase--that of the invention
preceding all demonstration--is easy to locate. We know that
Tycho-Brahe, lacking inventive genius but rich in capacity for exact
observation, met Kepler, an adventurous spirit: together, the two made a
complete scientist. We have seen how Kepler, guided by a preconceived
notion of the "harmony of the spheres," after many trials and
corrections, ended by discovering his laws. Copernicus recognized
expressly that his theory was suggested to him by an hypothesis of
Pythagoras--that of a revolution of the earth about a central fire,
assumed to be in a fixed position. Newton imagined his hypothesis of
gravitation from the year 1666 on, then abandoned it, the result of his
calculations disagreeing with observation; finally he took it up again
after a lapse of a few years, having obtained from Paris the new measure
of the terrestrial meridian that permitted him to prove his guess. In
relating his discoveries, Lavoisier is lavish in expressions that leave
no doubt as to their originally conjectural character. "He suspects
that the air of the atmosphere is not a simple thing, but is composed of
two very different substances." "He presumes that the permanent
alkalies (potash, soda) and the earths (lime, magnesia) should not be
considered simple substances." And he adds: "What I present here is at
the most no more than a mere conjecture." We have mentioned above the
case of Darwin. Besides, the history of scientific discoveries is full
of facts of this sort.
The passage from the imaginative to the rational phase may be slow or
sudden. "For eight months," says Kepler, "I have seen a first glimmer;
for three months, daylight; for the last week I see the sunlight of the
most wonderful contemplation." On the other hand, Hauey drops a bit of
crystallized calcium spar, and, looking at one of the broken prisms,
cries out, "All is found!" and immediately verifies his quick intuition
in regard to the true nature of crystallization. We have already
indicated the psychological reasons for these differences.
Underneath all the reasoning, inductions, deductions, calculations,
demonstrations, methods, and logical apparatus of every sort, there is
something animating them that is not understood, that is the work of
that complex operation--the constructive imagination.
To conclude: The hypothesis is a creation of the mind, invested with a
provisional reality that may, after verification, become permanent.
False hypotheses are characterized as imaginary, by which designation is
meant that they have not become freed from the first state. But for
psychology they are different neither in their origin nor in their
nature from those scientific hypotheses that, subjected to the power of
reason or of experiment, have come out victorious. Besides, in addition
to abortive hypotheses, there are dethroned ones. What theory was more
clinging, more fascinating in its applications, than that of phlogiston?
Kant praised it as one of the greatest discoveries of the
eighteenth century. The development of the sciences is replete with
these downfalls. They are psychological regressions: the invention,
considered for a time as adequate to reality, decays, returns to the
imaginative phase whence it seems to have emerged, and remains pure
imagination.
IV
Imagination is not absent from the third stage of scientific research,
in demonstration and experimentation, but here we must be brief, (1)
because it passes to a minor place, yielding its rank to other modes of
investigation, and (2) because this study would have to become doubly
employed with the practical and mechanical imagination, which will
occupy our attention later. The imagination is here only an auxiliary, a
useful instrument, serving:
(1) In the sciences of reasoning, to discover ingenious methods of
demonstration, stratagems for avoiding or overcoming difficulties.
(2) In the experimental sciences for inventing methods of research or of
control--whence its analogy, above mentioned, to the practical
imagination. Furthermore, the reciprocal influence of these two forms of
imagination is a matter of common observation: a scientific discovery
permits the invention of new instruments; the invention of new
instruments makes possible experiments that are increasingly more
complicated and delicate.
One remark further: This constructive imagination at the third stage is
the only one met with in many scientists. They lack genius for
invention, but discover details, additions, corrections, improvements. A
recent author distinguishes (a) those who have created the hypothesis,
prepared the experiments, and imagined the appropriate apparatus; (b)
those who have imagined the hypothesis and the experiment, but use means
already invented; and (c) those who, having found the hypothesis made
and demonstrated, have thought out a new method of verification.
The scientific imagination becomes poorer as we follow it down this
scale, which, however, bears no relation to exactness of reasoning and
firmness of method.
Neglecting species and varieties, we may reduce the fundamental
characters of the scientific imagination to the following:
For its material, it has concepts, the degree of abstraction of which
varies with the nature of the science.
It employs only those associational forms that have an objective basis,
although its mission is to form new combinations, "the discoveries
consisting of the relation of ideas, capable of being united, which
hitherto have been isolated." (Laplace.) All association with an
affective basis is strictly excluded.
It aims toward objectivity: in its conjectural construction it attempts
to reproduce the order and connection of things. Whence its natural
affinity for realistic art, which is midway between fiction and reality.
It is unifying, and so just the opposite of the esthetic imagination,
which is rather developmental. It puts forward the master idea (Claude
Bernard's idee directrice), a center of attraction and impulse that
enlivens the entire work. The principle of unity, without which no
creation succeeds, is nowhere more visible than in the scientific
imagination. Even when illusory, it is useful. Pasteur, scrupulous
scientist that he was, did not hesitate to say: "The experimenter's
illusions are a part of his power: they are the preconceived ideas
serving as guides for him."
V
It does not seem to me wrong to regard the imagination of the
metaphysician as a variety of the scientific imagination. Both arise
from one and the same requirement. Several times before this we have
emphasized this point--that the various forms of imagination are not the
work of an alleged "creative instinct," but that each particular one has
arisen from a special need. The scientific imagination has for its prime
motive the need of partial knowledge or explanation; the metaphysical
imagination has for its prime motive the need of a total or complete
explanation. The latter is no longer an endeavor on a restricted group
of phenomena, but a conjecture as to the totality of things, as
aspiration toward completely unified knowledge, a need of final
explanation that, for certain minds, is just as imperious as any other
need.
This necessity is expressed by the creation of a cosmic or human
hypothesis constructed after the type and methods of scientific
hypotheses, but radically subjective in its origin--only apparently
objective. It is a rationalized myth.
The three moments requisite for the constitution of a science are found
here, but in a modified form: reflection replaces observation, the
choice of the hypothesis becomes all-important, and its application to
everything corresponds to scientific proof.
(1) The first moment or preparatory stage, does not belong to our
subject. It requires, however, a word in passing. In all science,
whether well or ill established, firm or weak, we start from facts
derived from observation or experiment. Here, facts are replaced by
general ideas. The terminus of every science is, then, the
starting-point of philosophical speculation:--metaphysics begins where
each separate science ends; and the limits of the latter are theories,
hypotheses. These hypotheses become working material for metaphysics
which, consequently, is an hypothesis built on hypotheses, a conjecture
grafted on conjecture, a work of imagination superimposed on works of
imagination. Its principal source, then, is imagination, to which
reflection applies itself.
Metaphysicians, indeed, hold that the object of their researches, far
from being symbolic and abstract, as in science, or fictitious and
imaginary, as in art, is the very essence of things,--absolute reality.
Unfortunately, they have never proven that it suffices to seek in order
to find, and to wish in order to get.
(2) The second stage is critical. It is concerned with finding the
principle that rules and explains everything. In the invention of his
theory the metaphysician gives his measure, and permits us to value his
imaginative power. But the hypothesis, which in science is always
provisional and revocable, is here the supreme reality, the fixed
position, the inconcussum quid.
The choice of the principle depends on several causes: The chief of
these is the creator's individuality. Every metaphysician has a point of
view, a personal way of contemplating and interpreting the totality of
things, a belief that tends to recruit adherents.
Secondary causes are: the influence of earlier systems, the sum of
acquired knowledge, the social milieu, the variable predominance of
religions, sciences, morality, esthetic culture.
Without troubling ourselves with classifications, otherwise very
numerous, into which we may group systems (idealism, materialism,
monism, etc.) we shall, for our purpose, divide metaphysicians into the
imaginative and rational, according as the imagination is superior to
the reason or the reason rules the imagination. The differences between
these two types of mind, already clearly shown in the choice of the
hypothesis, are proven in its development.
(3) The fundamental principle, indeed, must come out of its state of
involution and justify its universal validity by explaining everything.
This is the third moment, when the scientific process of verification is
replaced by a process of construction.
All imaginative metaphysics have a dynamic basis, e.g., the Platonic
Ideas, Leibniz' Monadology, the Nature-philosophy of Schelling,
Schopenhauer's Will, and Hartmann's Unconscious, the mystics, the
systems that assume a world-soul, etc. Semi-abstract, semi-poetic
constructions, they are permeated with imagination not only in the
general conception, but also in the numberless details of its
application. Such are the "fulgurations" of Leibniz, those very rich
digressions of Schopenhauer, etc. They have the fascination of a work of
art as much as that of science, and this is no longer questioned by
metaphysicians themselves; they are living things.
Rational metaphysics, on the other hand, have a chilly aspect, which
brings them nearer the abstract sciences. Such are most of the
mechanical conceptions, the Hegelian Dialectic, Spinoza's construction
more geometrico, the Summa of the Middle Ages. These are buildings
of concepts solidly cemented together with logical relations. But art is
not wholly absent; it is seen in the systematic concatenation, in the
beautiful ordering, in the symmetry of division, in the skill with which
the generative principle is constantly brought in, in showing it
ever-present, explaining everything. It has been possible to compare
these systems with the architecture of the Gothic cathedrals, in which
the dominant idea is incessantly repeated in the numberless details of
the construction, and in the branching multiplicity of ornamentation.
Further, whatever view we adopt as to its ultimate value, it must be
recognized that the imagination of the great metaphysicians, by the
originality and fearlessness of its conceptions, by its skill in
perfecting all parts of its work, is inferior to no other form. It is
equal to the highest, if it does not indeed surpass them.