nature of that activity and its relation to the stages of progress
which preceded and followed its beginning. The superficial observer,
who sees the oak but forgets the acorn, might tell us that the special
qualities which have brought out such great results are expert
scientific knowledge and rare ingenuity, directed to the application of
the powers of steam and electricity. From this point of view the great
inventors and the great captains of industry were the first agents in
bringing about the modern era. But the more careful inquirer will see
that the work of these men was possible only through a knowledge of the
laws of nature, which had been gained by men whose work took precedence
of theirs in logical order, and that success in invention has been
measured by completeness in such knowledge. While giving all due honor
to the great inventors, let us remember that the first place is that of
the great investigators, whose forceful intellects opened the way to
secrets previously hidden from men. Let it be an honor and not a
reproach to these men that they were not actuated by the love of gain,
and did not keep utilitarian ends in view in the pursuit of their
researches. If it seems that in neglecting such ends they were leaving
undone the most important part of their work, let us remember that
Nature turns a forbidding face to those who pay her court with the hope
of gain, and is responsive only to those suitors whose love for her is
pure and undefiled. Not only is the special genius required in the
investigator not that generally best adapted to applying the
discoveries which he makes, but the result of his having sordid ends in
view would be to narrow the field of his efforts, and exercise a
depressing effect upon his activities. The true man of science has no
such expression in his vocabulary as "useful knowledge." His domain is
as wide as nature itself, and he best fulfils his mission when he
leaves to others the task of applying the knowledge he gives to the
world.
We have here the explanation of the well-known fact that the functions
of the investigator of the laws of nature, and of the inventor who
applies these laws to utilitarian purposes, are rarely united in the
same person. If the one conspicuous exception which the past century
presents to this rule is not unique, we should probably have to go back
to Watt to find another.
From this view-point it is clear that the primary agent in the movement
which has elevated man to the masterful position he now occupies is the
scientific investigator. He it is whose work has deprived plague and
pestilence of their terrors, alleviated human suffering, girdled the
earth with the electric wire, bound the continent with the iron way,
and made neighbors of the most distant nations. As the first agent
which has made possible this meeting of his representatives, let his
evolution be this day our worthy theme. As we follow the evolution of
an organism by studying the stages of its growth, so we have to show
how the work of the scientific investigator is related to the
ineffectual efforts of his predecessors.
In our time we think of the process of development in nature as one
going continuously forward through the combination of the opposite
processes of evolution and dissolution. The tendency of our thought has
been in the direction of banishing cataclysms to the theological limbo,
and viewing Nature as a sleepless plodder, endowed with infinite
patience, waiting through long ages for results. I do not contest the
truth of the principle of continuity on which this view is based. But
it fails to make known to us the whole truth. The building of a ship
from the time that her keel is laid until she is making her way across
the ocean is a slow and gradual process; yet there is a cataclysmic
epoch opening up a new era in her history. It is the moment when, after
lying for months or years a dead, inert, immovable mass, she is
suddenly endowed with the power of motion, and, as if imbued with life,
glides into the stream, eager to begin the career for which she was
designed.
I think it is thus in the development of humanity. Long ages may pass
during which a race, to all external observation, appears to be making
no real progress. Additions may be made to learning, and the records of
history may constantly grow, but there is nothing in its sphere of
thought, or in the features of its life, that can be called essentially
new. Yet, Nature may have been all along slowly working in a way which
evades our scrutiny, until the result of her operations suddenly
appears in a new and revolutionary movement, carrying the race to a
higher plane of civilization.
It is not difficult to point out such epochs in human progress. The
greatest of all, because it was the first, is one of which we find no
record either in written or geological history. It was the epoch when
our progenitors first took conscious thought of the morrow, first used
the crude weapons which Nature had placed within their reach to kill
their prey, first built a fire to warm their bodies and cook their
food. I love to fancy that there was some one first man, the Adam of
evolution, who did all this, and who used the power thus acquired to
show his fellows how they might profit by his example. When the members
of the tribe or community which he gathered around him began to
conceive of life as a whole--to include yesterday, to-day, and
to-morrow in the same mental grasp--to think how they might apply the
gifts of Nature to their own uses--a movement was begun which should
ultimately lead to civilization.
Long indeed must have been the ages required for the development of
this rudest primitive community into the civilization revealed to us by
the most ancient tablets of Egypt and Assyria. After spoken language
was developed, and after the rude representation of ideas by visible
marks drawn to resemble them had long been practised, some Cadmus must
have invented an alphabet. When the use of written language was thus
introduced, the word of command ceased to be confined to the range of
the human voice, and it became possible for master minds to extend
their influence as far as a written message could be carried. Then were
communities gathered into provinces; provinces into kingdoms, kingdoms
into great empires of antiquity. Then arose a stage of civilization
which we find pictured in the most ancient records--a stage in which
men were governed by laws that were perhaps as wisely adapted to their
conditions as our laws are to ours--in which the phenomena of nature
were rudely observed, and striking occurrences in the earth or in the
heavens recorded in the annals of the nation.
Vast was the progress of knowledge during the interval between these
empires and the century in which modern science began. Yet, if I am
right in making a distinction between the slow and regular steps of
progress, each growing naturally out of that which preceded it, and the
entrance of the mind at some fairly definite epoch into an entirely new
sphere of activity, it would appear that there was only one such epoch
during the entire interval. This was when abstract geometrical
reasoning commenced, and astronomical observations aiming at precision
were recorded, compared, and discussed. Closely associated with it must
have been the construction of the forms of logic. The radical
difference between the demonstration of a theorem of geometry and the
reasoning of every-day life which the masses of men must have practised
from the beginning, and which few even to-day ever get beyond, is so
evident at a glance that I need not dwell upon it. The principal
feature of this advance is that, by one of those antinomies of human
intellect of which examples are not wanting even in our own time, the
development of abstract ideas preceded the concrete knowledge of
natural phenomena. When we reflect that in the geometry of Euclid the
science of space was brought to such logical perfection that even
to-day its teachers are not agreed as to the practicability of any
great improvement upon it, we cannot avoid the feeling that a very
slight change in the direction of the intellectual activity of the
Greeks would have led to the beginning of natural science. But it would
seem that the very purity and perfection which was aimed at in their
system of geometry stood in the way of any extension or application of
its methods and spirit to the field of nature. One example of this is
worthy of attention. In modern teaching the idea of magnitude as
generated by motion is freely introduced. A line is described by a
moving point; a plane by a moving line; a solid by a moving plane. It
may, at first sight, seem singular that this conception finds no place
in the Euclidian system. But we may regard the omission as a mark of
logical purity and rigor. Had the real or supposed advantages of
introducing motion into geometrical conceptions been suggested to
Euclid, we may suppose him to have replied that the theorems of space
are independent of time; that the idea of motion necessarily implies
time, and that, in consequence, to avail ourselves of it would be to
introduce an extraneous element into geometry.
It is quite possible that the contempt of the ancient philosophers for
the practical application of their science, which has continued in some
form to our own time, and which is not altogether unwholesome, was a
powerful factor in the same direction. The result was that, in keeping
geometry pure from ideas which did not belong to it, it failed to form
what might otherwise have been the basis of physical science. Its
founders missed the discovery that methods similar to those of
geometric demonstration could be extended into other and wider fields
than that of space. Thus not only the development of applied geometry
but the reduction of other conceptions to a rigorous mathematical form
was indefinitely postponed.
There is, however, one science which admitted of the immediate
application of the theorems of geometry, and which did not require the
application of the experimental method. Astronomy is necessarily a
science of observation pure and simple, in which experiment can have no
place except as an auxiliary. The vague accounts of striking celestial
phenomena handed down by the priests and astrologers of antiquity were
followed in the time of the Greeks by observations having, in form at
least, a rude approach to precision, though nothing like the degree of
precision that the astronomer of to-day would reach with the naked eye,
aided by such instruments as he could fashion from the tools at the
command of the ancients.
The rude observations commenced by the Babylonians were continued with
gradually improving instruments--first by the Greeks and afterwards by
the Arabs--but the results failed to afford any insight into the true
relation of the earth to the heavens. What was most remarkable in this
failure is that, to take a first step forward which would have led on
to success, no more was necessary than a course of abstract thinking
vastly easier than that required for working out the problems of
geometry. That space is infinite is an unexpressed axiom, tacitly
assumed by Euclid and his successors. Combining this with the most
elementary consideration of the properties of the triangle, it would be
seen that a body of any given size could be placed at such a distance
in space as to appear to us like a point. Hence a body as large as our
earth, which was known to be a globe from the time that the ancient
Phoenicians navigated the Mediterranean, if placed in the heavens at a
sufficient distance, would look like a star. The obvious conclusion
that the stars might be bodies like our globe, shining either by their
own light or by that of the sun, would have been a first step to the
understanding of the true system of the world.
There is historic evidence that this deduction did not wholly escape
the Greek thinkers. It is true that the critical student will assign
little weight to the current belief that the vague theory of
Pythagoras--that fire was at the centre of all things--implies a
conception of the heliocentric theory of the solar system. But the
testimony of Archimedes, confused though it is in form, leaves no
serious doubt that Aristarchus of Samos not only propounded the view
that the earth revolves both on its own axis and around the sun, but
that he correctly removed the great stumbling-block in the way of this
theory by adding that the distance of the fixed stars was infinitely
greater than the dimensions of the earth's orbit. Even the world of
philosophy was not yet ready for this conception, and, so far from
seeing the reasonableness of the explanation, we find Ptolemy arguing
against the rotation of the earth on grounds which careful observations
of the phenomena around him would have shown to be ill-founded.
Physical science, if we can apply that term to an uncoordinated body of
facts, was successfully cultivated from the earliest times. Something
must have been known of the properties of metals, and the art of
extracting them from their ores must have been practised, from the time
that coins and medals were first stamped. The properties of the most
common compounds were discovered by alchemists in their vain search for
the philosopher's stone, but no actual progress worthy of the name
rewarded the practitioners of the black art.
Perhaps the first approach to a correct method was that of Archimedes,
who by much thinking worked out the law of the lever, reached the
conception of the centre of gravity, and demonstrated the first
principles of hydrostatics. It is remarkable that he did not extend his
researches into the phenomena of motion, whether spontaneous or
produced by force. The stationary condition of the human intellect is
most strikingly illustrated by the fact that not until the time of
Leonardo was any substantial advance made on his discovery. To sum up
in one sentence the most characteristic feature of ancient and medieval
science, we see a notable contrast between the precision of thought
implied in the construction and demonstration of geometrical theorems
and the vague indefinite character of the ideas of natural phenomena
generally, a contrast which did not disappear until the foundations of
modern science began to be laid.
We should miss the most essential point of the difference between
medieval and modern learning if we looked upon it as mainly a
difference either in the precision or the amount of knowledge. The
development of both of these qualities would, under any circumstances,
have been slow and gradual, but sure. We can hardly suppose that any
one generation, or even any one century, would have seen the complete
substitution of exact for inexact ideas. Slowness of growth is as
inevitable in the case of knowledge as in that of a growing organism.
The most essential point of difference is one of those seemingly slight
ones, the importance of which we are too apt to overlook. It was like
the drop of blood in the wrong place, which some one has told us makes
all the difference between a philosopher and a maniac. It was all the
difference between a living tree and a dead one, between an inert mass
and a growing organism. The transition of knowledge from the dead to
the living form must, in any complete review of the subject, be looked
upon as the really great event of modern times. Before this event the
intellect was bound down by a scholasticism which regarded knowledge as
a rounded whole, the parts of which were written in books and carried
in the minds of learned men. The student was taught from the beginning
of his work to look upon authority as the foundation of his beliefs.
The older the authority the greater the weight it carried. So effective
was this teaching that it seems never to have occurred to individual
men that they had all the opportunities ever enjoyed by Aristotle of
discovering truth, with the added advantage of all his knowledge to
begin with. Advanced as was the development of formal logic, that
practical logic was wanting which could see that the last of a series
of authorities, every one of which rested on those which preceded it,
could never form a surer foundation for any doctrine than that supplied
by its original propounder.
The result of this view of knowledge was that, although during the
fifteen centuries following the death of the geometer of Syracuse great
universities were founded at which generations of professors expounded
all the learning of their time, neither professor nor student ever
suspected what latent possibilities of good were concealed in the most
familiar operations of Nature. Every one felt the wind blow, saw water
boil, and heard the thunder crash, but never thought of investigating
the forces here at play. Up to the middle of the fifteenth century the
most acute observer could scarcely have seen the dawn of a new era.
In view of this state of things it must be regarded as one of the most
remarkable facts in evolutionary history that four or five men, whose
mental constitution was either typical of the new order of things, or
who were powerful agents in bringing it about, were all born during the
fifteenth century, four of them at least, at so nearly the same time as
to be contemporaries.
Leonardo da Vinci, whose artistic genius has charmed succeeding
generations, was also the first practical engineer of his time, and the
first man after Archimedes to make a substantial advance in developing
the laws of motion. That the world was not prepared to make use of his
scientific discoveries does not detract from the significance which
must attach to the period of his birth.
Shortly after him was born the great navigator whose bold spirit was to
make known a new world, thus giving to commercial enterprise that
impetus which was so powerful an agent in bringing about a revolution
in the thoughts of men.
The birth of Columbus was soon followed by that of Copernicus, the
first after Aristarchus to demonstrate the true system of the world. In
him more than in any of his contemporaries do we see the struggle
between the old forms of thought and the new. It seems almost pathetic
and is certainly most suggestive of the general view of knowledge taken
at that time that, instead of claiming credit for bringing to light
great truths before unknown, he made a labored attempt to show that,
after all, there was nothing really new in his system, which he claimed
to date from Pythagoras and Philolaus. In this connection it is curious
that he makes no mention of Aristarchus, who I think will be regarded
by conservative historians as his only demonstrated predecessor. To the
hold of the older ideas upon his mind we must attribute the fact that
in constructing his system he took great pains to make as little change
as possible in ancient conceptions.
Luther, the greatest thought-stirrer of them all, practically of the
same generation with Copernicus, Leonardo and Columbus, does not come
in as a scientific investigator, but as the great loosener of chains
which had so fettered the intellect of men that they dared not think
otherwise than as the authorities thought.
Almost coeval with the advent of these intellects was the invention of
printing with movable type. Gutenberg was born during the first decade
of the century, and his associates and others credited with the
invention not many years afterwards. If we accept the principle on
which I am basing my argument, that in bringing out the springs of our
progress we should assign the first place to the birth of those psychic
agencies which started men on new lines of thought, then surely was the
fifteenth the wonderful century.
Let us not forget that, in assigning the actors then born to their
places, we are not narrating history, but studying a special phase of
evolution. It matters not for us that no university invited Leonardo to
its halls, and that his science was valued by his contemporaries only
as an adjunct to the art of engineering. The great fact still is that
he was the first of mankind to propound laws of motion. It is not for
anything in Luther's doctrines that he finds a place in our scheme. No
matter for us whether they were sound or not. What he did towards the
evolution of the scientific investigator was to show by his example
that a man might question the best-established and most venerable
authority and still live--still preserve his intellectual
integrity--still command a hearing from nations and their rulers. It
matters not for us whether Columbus ever knew that he had discovered a
new continent. His work was to teach that neither hydra, chimera nor
abyss--neither divine injunction nor infernal machination--was in the
way of men visiting every part of the globe, and that the problem of
conquering the world reduced itself to one of sails and rigging, hull
and compass. The better part of Copernicus was to direct man to a
view-point whence he should see that the heavens were of like matter
with the earth. All this done, the acorn was planted from which the oak
of our civilization should spring. The mad quest for gold which
followed the discovery of Columbus, the questionings which absorbed the
attention of the learned, the indignation excited by the seeming
vagaries of a Paracelsus, the fear and trembling lest the strange
doctrine of Copernicus should undermine the faith of centuries, were
all helps to the germination of the seed--stimuli to thought which
urged it on to explore the new fields opened up to its occupation. This
given, all that has since followed came out in regular order of
development, and need be here considered only in those phases having a
special relation to the purpose of our present meeting.
So slow was the growth at first that the sixteenth century may scarcely
have recognized the inauguration of a new era. Torricelli and Benedetti
were of the third generation after Leonardo, and Galileo, the first to
make a substantial advance upon his theory, was born more than a
century after him. Only two or three men appeared in a generation who,
working alone, could make real progress in discovery, and even these
could do little in leavening the minds of their fellowmen with the new
ideas.
Up to the middle of the seventeenth century an agent which all
experience since that time shows to be necessary to the most productive
intellectual activity was wanting. This was the attrition of like
minds, making suggestions to one another, criticising, comparing, and
reasoning. This element was introduced by the organization of the Royal
Society of London and the Academy of Sciences of Paris.
The members of these two bodies seem like ingenious youth suddenly
thrown into a new world of interesting objects, the purposes and
relations of which they had to discover. The novelty of the situation
is strikingly shown in the questions which occupied the minds of the
incipient investigators. One natural result of British maritime
enterprise was that the aspirations of the Fellows of the Royal Society
were not confined to any continent or hemisphere. Inquiries were sent
all the way to Batavia to know "whether there be a hill in Sumatra
which burneth continually, and a fountain which runneth pure balsam."
The astronomical precision with which it seemed possible that
physiological operations might go on was evinced by the inquiry whether
the Indians can so prepare that stupefying herb Datura that "they make
it lie several days, months, years, according as they will, in a man's
body without doing him any harm, and at the end kill him without
missing an hour's time." Of this continent one of the inquiries was
whether there be a tree in Mexico that yields water, wine, vinegar,
milk, honey, wax, thread and needles.
Among the problems before the Paris Academy of Sciences those of
physiology and biology took a prominent place. The distillation of
compounds had long been practised, and the fact that the more
spirituous elements of certain substances were thus separated naturally
led to the question whether the essential essences of life might not be
discoverable in the same way. In order that all might participate in
the experiments, they were conducted in open session of the academy,
thus guarding against the danger of any one member obtaining for his
exclusive personal use a possible elixir of life. A wide range of the
animal and vegetable kingdom, including cats, dogs and birds of various
species, were thus analyzed. The practice of dissection was introduced
on a large scale. That of the cadaver of an elephant occupied several
sessions, and was of such interest that the monarch himself was a
spectator.
To the same epoch with the formation and first work of these two bodies
belongs the invention of a mathematical method which in its importance
to the advance of exact science may be classed with the invention of
the alphabet in its relation to the progress of society at large. The
use of algebraic symbols to represent quantities had its origin before
the commencement of the new era, and gradually grew into a highly
developed form during the first two centuries of that era. But this
method could represent quantities only as fixed. It is true that the
elasticity inherent in the use of such symbols permitted of their being
applied to any and every quantity; yet, in any one application, the
quantity was considered as fixed and definite. But most of the
magnitudes of nature are in a state of continual variation; indeed,
since all motion is variation, the latter is a universal characteristic
of all phenomena. No serious advance could be made in the application
of algebraic language to the expression of physical phenomena until it
could be so extended as to express variation in quantities, as well as
the quantities themselves. This extension, worked out independently by
Newton and Leibnitz, may be classed as the most fruitful of conceptions
in exact science. With it the way was opened for the unimpeded and
continually accelerated progress of the last two centuries.