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See also:SCIENCE (See also:Lat. scientia, from scire; to learn, know) , a word which, in its broadest sense, is synonymous with learning and knowledge . Accordingly it can be used in connexion with any qualifying See also:adjective, which shows what See also:branch of learning is meant . But in See also:general usage a more restricted meaning has been adopted, which differentiates " See also:science " from other branches of accurate knowledge . For our purpose, science may be defined as ordered knowledge of natural phenomena and of the relations between them; thus it is a See also:short See also:term for " natural science," and as such is used here technically in conformity with a general See also:modern See also:convention . The beginnings of See also:physical science are to be sought in the slow and unconscious observation by See also:primitive races of men of natural occurrences, such as the apparent movements of the heavenly bodies, and in the gradually The i acquired mastery over the See also:rude implements by the of science. aid of which such men strove to increase the See also:security and comfort of their lives . Biological science similarly must have begun with observation of the See also:plants and animals useful to See also:man, and with empirical See also:medicine and See also:surgery . It was only when a considerable progress had been made with ordered knowledge that men began to ask questions about the meaning and causes of the phenomena, and to discern the connexions between them . In the earliest See also:stage of development it seems that an anthropomorphic or mythological explanation is always assigned to the phenomena of nature . With no See also:clue to trace the regularity of sequence and connexion between those phenomena, an untutored mind inevitably refers the apparently capricious events which succeed each other to the See also:direct and immediate intervention of some unseen being of a nature essentially similar to his own . The See also:sun is the flaming See also:chariot of the sun-See also:god, driven See also:day by day across the heavens; the clouds are cows from which See also:milk descends as nourishing See also:rain on the fruitful See also:earth . We may regard such myths as childlike fancies, but they were doubtless an advance on the want of all explanation which preceded them; they supplied hypotheses which, besides giving rise to themes of beauty and suggestiveness for See also:poetry and See also:art, played the first and See also:chief See also:part of a scientific See also:hypothesis in pointing the way for further inquiry . Much useful knowledge was acquired and much skill gained in logical See also:analysis before these primitive explanations were proved insufficient .
A false theory which can be compared with facts may be more useful at a given stage of development than a true one beyond the comprehension of the See also:time, and incapable of examination by observation or experiment by any means then known
.
The Newtonian theory of See also:gravitation might be useless to a See also:savage, to whose mind the animistic view of nature brought conviction and helpful ideas, which he could test by experience
.
The phenomena of the heavens are at once the most striking, the most easily observed and the most See also:regular of those which
are impressed inevitably on the minds of thinking men
.
Thus it is to See also:astronomy we must look for the first development of See also:early as- scientific ideas
.
The See also:orientation of many prehistoric tronomy. monuments shows that a certain amount of astro-
nomical observation had been acquired at a very early See also:age, and the Chaldeans seem to have gone so far as to recognize a See also:law of periodicity even in eclipses
.
From the See also:land of See also:Asia the Greeks took their earliest ideas of science, and it is to the Ionian philosophers, of whom Thales of See also:Miletus (58o B.c.) is regarded as the first, that we must turn for the earliest known example of an advance on the mythological view of nature
.
Anaximenes recognized the rotation of the heavens See also:round the See also:pole See also:star, and saw that the See also:dome overhead was but the See also:half of a See also:complete See also:sphere
.
The earth was thus deprived of the See also:base stretching to unfathomed depths imagined by the mythologists, and See also:left See also:free to See also:float as a flattened See also:cylinder at the centre of the See also:celestial sphere
.
Anaximenes, too, seems to have grasped the See also:doctrine of the uniformity of nature, teaching that all material transformations rnust have a true cause
.
Next came the Pythagoreans, who simplified these conceptions by the See also:suggestion that instead of a rotation of the vast sphere of the heavens the earth itself might be a sphere and revolve about a central fixed point, like a See also: See also:Mythology was losing its hold of science, but mystical symbolism still held sway . When, however, in the 4th See also:century B.C. the growth of See also:geographical See also:discovery failed to disclose any trace of this central fire, the See also:idea of its existence faded away, and was replaced by the conception of the revolution of the earth on its own See also:axis . Finally, See also:Aristarchus (28o B.C.), believing that the sun was larger than the earth, thought it unlikely that it should revolve round the earth, and See also:developed a See also:heliocentric theory . But the time was not ripe; no indisputable See also:evidence could be adduced, no general conviction followed, and to mankind the earth remained the centre of creation till many centuries later . Even to See also:Lucretius, the visible universe consisted of the central earth with its attendant See also:water, See also:air and See also:aether founded by the sphere of the heavens, which formed the flaming walls of the worldfl¢mmantia moenia mundi . Simultaneously with the See also:birth of astronomy the problem of See also:matter came into being . The old Ionian nature philosophers, observing the sequence of changes from earth and The water into the structure of plants and the bodies of problem of animals, an , and through them again into the See also:original constituents, began to grasp the conception of the indestructibility of matter, and to put forward the idea that all forms of matter might ultimately consist of a single " See also:element." But the conception of a single ultimate basis of matter was far in advance of the age . It is only now becoming a fertile working hypothesis in the See also:light of all the gigantic increase in knowledge of the intervening two thousand years . At the time when it was put forward, the conception was of little use, and the immediate path of advance was found in the idea of See also:Empedocles (45o B.c.) that the See also:primary elements were four: earth, water, air and fire—a solid, a liquid, a See also:gas and the See also:flame which seemed to the ancients a type of matter of still rarer structure . This hypothesis served to interpret the phenomena of nature for many centuries, till, in modern days, the growth of See also:chemistry disclosed the seventy or eighty elements of our See also:text-books . Signs are not wanting that they too have served their turn as a conception of the ultimate nature of matter, while still maintaining their See also:place as the proximate See also:units of chemical See also:action . In the four elements of Empedocles we trace the germ of the ideas of the Atomists . Empedocles saw that, by combining his See also:separate elements in different proportions, he could The theory of atoms. explain all the endless See also:differences in matter as known to the senses . Leucippus and See also:Democritus developed the conception and gave to the See also:world the theory of atoms, described at a later date by the See also:Roman poet Lucretius . As matter is subdivided does it keep its characteristic properties throughout ? Is See also:iron always iron, however finely we See also:divide it; is water always water ? Are the properties of any See also:kind of matter ultimate facts of which no explanation—no description in simpler terms—is possible ? To avoid answering this last question in the affirmative, and resigning all See also:hope of an advance in knowledge, the atomic theory of the Greeks was framed . To recognize the significance of the doctrines of the See also:Greek Atomists, we must remove from our minds all sense of comparison with the atomic theory of to-day . The Greeks had none of the detailed physical and chemical knowledge on which that theory is founded, and which it was framed to explain . The See also:object of Leucippus and Democritus was quite different from that of See also:Dalton and See also:Avogadro . To the latter, the conception of atoms and molecules served as a means of explaining certain definite and detailed facts of chemical See also:combination and gaseous See also:volume in a more definite and exact way than any other hypothesis available at the time . To the Greek philosophers, the atomic theory was an See also:attempt to make the universe intelligible . The particular explanation offered was not of so much importance as the idea that an explanation of some kind was possible .
When we see the beliefs that held sway before their day, we realize the advance their ideas produced
.
The qualities of substances were thought to be of their essence—the sweetness of See also:sugar was as much a reality as sugar itself, the See also:black See also:colour of water must survive all changes in its See also:form, so that, to one who knew this doctrine, See also:snow could never look See also: But in the See also:ancient world this was not so . To test a new theory, other phenomena were very rarely available than those which suggested it, or to explain which it was put forward . Thus thought was much more speculative, and, as is still the See also:case with See also:meta-physics, no general consensus of See also:opinion was reached . Each philosopher had a See also:system of his own in science, just as he still has in See also:metaphysics—a system which, beginning from first principles anew, raises on them a superstructure, which, even if it logically follows from them, can have no more validity than the premises on which it is based . When the premises are not accepted by other philosophers, the whole See also:scheme becomes merely the doctrine of one man, and, if it lives at all, may oppress by the dead See also:weight of authority the struggle of living thought beneath it . The See also:history of the atomic theory of Leucippus and Democritus illustrates the difficulties of a position where See also:speculation has See also:Aristotle. outstripped observation . The theory was nearer what is now accepted as truth than any other of the ancient schemes of physics . Yet the grounds on which it was based were so insecure that Aristotle (c . 340 B.c.), who started with other preconceptions, was able to bring to See also:bear such destructive See also:criticism that the theory ceased to occupy the foremost place in Greek thought . Although, with the knowledge then available, we can but admit that some of Aristotle's criticism was just, much of it consists of metaphysical arguments against the atomists, while in parts he rejects true conclusions owing to what he considers their impossibility . Democritus, for instance, had held that all things would fall with equal See also:speed in a vacuum, and that the fact that heavy bodies were observed to fall faster than very light ones was due to the resistance of the air . Democritus's belief was true, though he was of course quite unconscious of the grounds on which it can alone be demonstrated—the universal attraction of gravity, and the remarkable and curious experimental fact that the weights of bodies are proportional to their masses . Aristotle agrees that in a vacuum all bodies would fall at an equal See also:rate, but the conclusion appears to him so inconceivable that he rejects the idea of the existence of any empty space at all, and with the " void " rejects the See also:rest of the allied concepts of the atomic theory . If all bodies were composed of the same ultimate matter, he argues, they must all be heavy, and nothing would be light in itself and disposed to rise . A large See also:mass of air or fire would then necessarily be heavier than a small mass of earth or water . This result he thinks impossible, for certain bodies always tend upwards and rise faster as their bulk increases . It will be seen that Aristotle has no idea of the conceptions we now See also:call See also:density and specific gravity, though clear views about the question why some things rise through water or air might have been obtained without the aid of physical apparatus . Aristotle's doctrine that bodies are essentially heavy or light in themselves persisted all through the See also:middle ages, and did much to delay the attainment of more exact knowledge . It was not till Galileo Galilei (1564–1642) discovered by actual experiment that, in cases where the resistance of the air is negligible, heavy things fall at the same speed as light ones, that the Aristotelian See also:dogma was overthrown . Turning to the biological sciences, we may trace a somewhat similar course of development . Owing to its See also:practical importance, medicine has left many records by which its progress can be traced . Just as primitive man personified the sun and the See also:moon, the See also:wind and the See also:sea, so he regarded disease as due to the action of some See also:malignant demon or to the spells of some human enemy . Once more Greek literature enables us to trace the See also:gradual decrease in the importance assigned to charms and magic, and the growth of more rational ideas among physicians . But here, as in the physical sciences, the philosophic range of the See also:intellect of the Greeks led them astray . Assumptions as to the nature of man or the origin of organic life were too often made the starting point of a See also:train of deductive reasoning, the consequences of which were not always compared with the results of observation and experiment, even where such comparison was possible . The Greek philosophers tried to make bricks without See also:straw, usually in See also:sublime unconsciousness that straw was necessary . Many centuries of humble observation and tentative fitting together of small parts of the great See also:puzzle were needed before enough material was collected to make possible useful generalizations about the questions, answers to which the Greeks assumed as the very basis of their inquiries . Among the multitude of their guesses, a few somewhat resembled the views that are now again rising into prominence from the basis of definite and exact experiment . A See also:good example of the strength and weakness of ancient speculation is found in the See also:cosmogony of the atomists, both on its physical and on its biological side . Lucretius describes how the world was formed by the See also:conjunction of streams of atoms, which condensed into the earth, with its attendant water, air and aether, to form a self-contained whole . Unconscious of the mighty See also:gap between inorganic matter and living beings, he proceeds to tell how, in the chances of See also:infinite time, all possible forms of life appeared, while only those fittest to survive persisted and reared offspring . Here, surrounded by unsupported statements and false conclusions, we see dimly the germs of the ideas of the nebular hypothesis and the theory of natural selection, though Lucretius had the profoundest See also:ignorance of the difficulties of the problem, and the vast stretches of time necessary for cosmical and biological development . In those branches of biological science in which less ambitious theorizing and more detailed observation were forced on the Greeks, considerable progress was made . Aristotle compiled a laborious See also:account of the animals known in his day, with many accurate details of their anatomical structure . Beginning from an earlier date, steady advance was made with geographical discovery . Maps of the known world, developed from the See also:local maps invented by the Egyptians for the purposes of land-See also:surveying, gave definiteness to the knowledge thus acquired, and showed its bearing on wider problems . One of the most striking successes of Greek thought is seen in the development of See also:geometry . Geometry has a twofold importance, as being itself the study of the properties Geometry of the space known to our senses, and as teaching us methods and means of studying nature by unfolding the full logical consequences of any hypothesis: geometry is the best type of deductive reasoning . Based on axioms, the result of See also:simple experience, it traces from the ideas of solids, surfaces, lines and points the properties of other figures defined in terms of those ideas . As an example to other sciences, the deductive geometry of See also:Euclid (c . 300 B.c.) had, perhaps, an unfortunate See also:influence in emphasizing the deductive method, and teaching men to neglect the need of verifying by experiment the theories put forward to explain the more complex phenomena of nature at the conclusion, and at each possible step, of the See also:deduction . But, in itself, the science of Euclidian geometry was brought to such a See also:state of perfection that no advance was made till modern times: no See also:change even in form attempted till quite recently . Unlike some other branches of inquiry we have mentioned, Euclid's geometry carried universal conviction, and represented a permanent step in advance which never had to be retraced . Alongside the study of individual sciences, the Greeks paid even more See also:attention to the See also:laws of thought, and to the examination of the essence of the methods by which knowledge in general is acquired . In opposition to See also:Plato's theory oTbeories that all knowledge is but the unfolding and develop- knowledge. ment of forgotten memories of a previous state of existence, Aristotle taught that we learn to reach the generalizations, which alone the Greeks regarded as knowledge, by remembering, comparing and co-ordinating numerous particular acts or judgments of sense, which are thus used as a means of gaining knowledge by the action of the innate and infallible nous or intellect . Neither Plato nor Aristotle could be satisfied without finding See also:infallibility somewhere . Aristotle, it is true, investigated the logical processes by which we pass from particular instances to general propositions, and laid stress on the importance of observing the facts before generalizing about them, but he had little appreciation of the conditions in which observation and the See also:induction based on it must be conducted in practice in See also:order to obtain results where the probability of See also:error is a minimum . Aristotle regarded induction merely as a necessary preliminary to true science of the deductive type best seen in geometry, and, in applying his principles, he never reached the " See also:positive " stage, in which metaphysical problems are evaded, if not excluded, Early See also:biology .
and a scheme of natural knowledge built up in a consistent manner, so that metaphysical ideas, though they may underlie the See also:foundation of the ultimate conceptions, do not intrude between the parts of the See also:building
.
Hence Aristotle's explanations often turn directly on metaphysical ideas such as form, cause, substance, terms which do not occur (in the Aristotelian sense) in modern scientific terminology
.
A century later than the time of Aristotle, See also:Archimedes of See also:Syracuse (287 to 212 B.c.) formulated the fundamental concep-
tions of See also:hydrostatics and took what may be regarded The as the first step in the exact science of See also:mechanics
.
origin of
mectranks
.
The use of the See also:lever must have been discovered at a
very early date, and Archimedes set to See also:work to investigate its quantitative laws by the application of principles learnt from the geometers
.
He begins by laying down two axioms: (1) Equal weights placed at equal distances from the point of support of a See also:bar will See also:balance: (2) Equal weights placed at unequal distances do not balance, but that which hangs at the greater distance descends
.
The ancient philosophers based such axioms as the first of these two on the " principle of sufficient See also:reason." No See also:motion can take place, because, from the symmetry of the system, there is no reason why the balance should descend on one side more than the other
.
Even if we See also: Nevertheless, Archimedes' proof is of use and See also:interest . On the assumptions made, it shows the connexion between the general case of the lever with unequal arms, and the See also:special and more See also:familiar case when the arms are equal . Indeed; if we also treat the principle of the centre of gravity as an axiom known by experience, Archimedes' proof is a true type of all scientific " explanations "; it reduces an unfamiliar phenomenon to others already well known to our minds, which, creatures of See also:habit as they are, regard the familiar cases as in no need of explanation . Nowadays we should treat the law of the lever of unequal arms as one that is verified by direct and familiar experiment, and use it, in its turn, as the starting point for further deduction . Thus before the intellectual activity of See also:Greece was absorbed by the See also:utilitarianism of See also:Rome, which, in its turn, was lost in the dark ages following the See also:barbarian conquests, the seeds were sown which, germinating after the See also:lapse cf centuries, developed in the more fruitful See also:soil of the age of experiment . But for a time they were buried, and only remembered by compendiums written just before the ancient light was wholly lost . During the dark ages, the contents of See also:secular learning, based on those compendiums, settled down into the elementary " See also:trivium," consisting of See also:grammar, See also:rhetoric and See also:dialectic, and the more advanced " quadrivium " See also:music, See also:arithmetic, geometry and astronomy . Music included a half-mystical doctrine of See also:numbers and the rules of plainsong; geometry consisted of a selection of the propositions of Euclid without the demonstrations; while arithmetic and astronomy were cultivated chiefly because they taught the means of finding See also:Easter . Meanwhile, the early alchemists of See also:Alexandria, by the aid of mystical analogies with the conceptions of See also:astrology, were making primitive experiments on the transformations of various substances . It was probably from them that the " sacred science" passed to the See also:Arabs, among whom See also:Geber (c . A.D . 75o) discovered many new chemical reactions and compounds .
With the intellectual revival which began in the rrth century, and the gradual recovery of some of the lost See also:works of the ancientwriters, we turn a new See also:page
.
The controversy between Plato and Aristotle upon the doctrine of ideas fascinated the minds of the middle ages, saturated as they were with the logical subtleties of dialectic
.
This controversy originated the long debate on the reality of universals, which absorbed the intellectual energies of many generations of men
.
Did reality belong only to the idea or universal—to the class rather than to the individual—to the See also:common humanity of mankind, for instance, rather than to each isolated being
?
Or were the individuals the reality, and the universals See also:mere names
?
In this question, trivial, almost meaningless, as it seems at first sight, logical analysis disclosed to the See also:medieval mind the whole theory of the universe
.
Either See also:answer contained danger to theological orthodoxy as then understood; hence the fervour with which it was debated
.
But, as communication with the See also:East was reopened early in the 13th century, Latin See also:translations of Aristotle's works gradually were recovered; the whole of Aristotle's See also:philosophy was reimported into the See also:schools of See also:Europe, and reconciled and adopted by See also:Christian See also:theology
.
For three See also:hundred years Aristotle reigned supreme in See also:European thought, and exponents of the scholastic philosophy, ignoring their See also:master's teaching on the need of experiment, settled questions of fact as well as those of opinion by an See also:appeal to his books
.
But outside the See also:academic schools of the newly founded See also:universities, experiment was kept alive by the .labours of the alchemists, who, early in the 13th century, caught their ideas from the Arabs, and began to See also:search for an See also:elixir vitae and for a means of transmuting baser metals into See also:gold
.
But See also:alchemy never quite squared its account with orthodox theology, and the " sacred science " of the Alexandrians became associated in the medieval mind with the " black art of See also:witchcraft
.
Even a man like See also:Roger See also: We now reach the See also:period in the history of the world known as the See also:Renaissance, when many converging streams of thought were given See also:room to join by the increased material The Re-prosperity and improved See also:political stability of the nalssance . 15th and 16th centuries . The Renaissance was not, as it is sometimes represented, a sudden break with medievalism and a birth of the modern world . But a number of conditions favourable to rapid development happened to coincide, and, in the course of a century, men's outlook on themselves and on nature became profoundly modified . The recovery of the Greek See also:language, the voyages of See also:Columbus, the decay of the Western and the passing of the Eastern See also:empire, the temporary diminution in See also:power of the papacy, the invention of See also:printing, all tended to produce new ideas and to prepare men's minds to accept the more human and naturalistic view of the universe which had been current among the Greeks, in place of the mystical aspect which it wore to the medieval schoolmen and ecclesiastics . At first the tendency was to substitute the authority of the ancients for the authority of the schoolmen, but gradually more See also:independence of thought was secured; men like Leonardo da See also:Vinci (1452–1519) began to experiment and to See also:record their results; Nicolaus See also:Copernicus (1473–1543) revived the heliocentric theory, and showed how the accumulated mass of astronomical observations could be interpreted by its means; and See also:anatomy began again to be studied in the schools of medicine, gradually making its way in See also:face of the See also:prejudice against mutilating the human body . The philosophy of the new experimental methods was first studied deeply by See also:Francis Bacon (1561–1626) . Sensible of the confused and disjointed See also:information which then con-Fr fta stituted the only scientific knowledge, Bacon set Bacon . Bacons himself to describe a new method by which definite knowledge might be acquired with certainty . Warned by the failure of the scholastic methods, Bacon laid exclusive stress on experimental See also:research, and it was perhaps natural that he should incline to the other extreme and ignore almost entirely the use of hypothesis and the deductive method . To arrive at the underlying causes, said Bacon, we must study the The dark ages . Medieval learning . natural history of the phenomena, collect and tabulate all observations which bear on them, See also:notice which phenomena are related in such a way as to vary together, and then, by a merely See also:mechanical See also:process of exclusion, we discover the cause of any given phenomenon . As a corrective of the medieval philosophy Bacon's work was of the greatest value in the history of thought, and, from this point of view, it is perhaps but a small See also:drawback that scientific discovery is seldom or never made by the pure Baconian method . The multitude of phenomena are too great for any subject to be attacked with success without the aid of hypothesis framed by the use of the scientific imagination . Facts are collected to prove or disprove the consequences deduced from the hypothesis, and thus the number of facts to be examined becomes manageable . Even while Bacon was philosophizing, the true method was being used by Galileo Galilei (1564–1642) to found the science Gav/eo. of See also:dynamics . We have seen how the Aristotelians held the belief that every body sought its natural place, the place of heavy bodies being below and that of light ones above . Innate qualities of heaviness and lightness were thus invoked to explain why some things See also:fell, and others, in similar circumstances, See also:rose . Galileo, rightly rejecting the whole current point of view, set himself to examine not why, but how, things fell . This change of attitude was in itself one of his great achievements . Now a falling body starts from rest and falls with a speed which is increasing constantly . Galileo sought to find the law of increase . To isolate the real law out of all possible laws he made a guess at a simple law which seemed likely to be true . He assumed that the speed acquired is proportional to the distance fallen through . But, working out the consequences of this hypothesis, he soon convinced himself that it involved a See also:contradiction . He abandoned the hypothesis and made another . He supposed that the speed was proportional to the time of fall . Again he deduced mathematically the consequences of this new hypothesis, and, finding no inconsistencies, put some of his deductions to the test of experiment, and verified their accuracy . Thus Galileo proved mathematically that, if the speed of fall is proportional to the time from the moment of starting, the space traversed by a falling body must be proportional to the square of the time of fall . To verify this result experimentally, Galileo convinced himself that a body falling down an inclined See also:plane acquired a speed which is the same as that it would have attained in falling through the same See also:vertical height . He was able therefore to use a slow fall down a plane for his experiments instead of the unmanageably rapid course of a body falling freely . Nor was this all . From this stage to the investigation another con-sequence of his results was found to See also:spring . A See also:ball after See also:running down an inclined plane of a certain height will run up another plane of the same height irrespective of its inclination—that is, if See also:friction be small . The second plane may be made very long, but still, if its final height be the same, the ball .will reach its end . Hence it is the height that matters; none of the speed of the ball is destroyed unless it rises . If the second plane be made See also:horizontal, the ball will thus run on for ever unless stopped by friction or some other applied force . This fundamental result, put into definite words by See also:Newton, is known as the first law of motion, and is the foundation of the whole science of dynamics . In Galileo's day it was an entirely new conception . It has been assumed that every motion required some cause or force to maintain it . Hence arose the need of hypothetical vortices to maintain planetary movements, and similar complications in astronomy and Mechanics . But it now became evident that it was not the continuous motion of the See also:planets which needed explanation, but the See also:constant deflection of that motion from the straight path it would hold if no applied force were in action . The way was open for Newton . See also:Sir See also:Isaac Newton (1642–1727) proved mathematically that the observed motion of the planets about the sun could be Newton. explained, and explained only, by the supposition that the sun exerted a force on each See also:planet proportional inversely to the square of its distance from the planet . But the earth, at any rate, does attract bodies on or near its See also:surface, the phenomenon being the familiar but mysterious gravity . Is this force competent to account for the motion of the moon round the earth ? On the See also:assumption of the law of inverse squares, Newton calculated what the known force of gravity would become at the distance of the moon . Owing to faulty data, his first result indicated that the force would be too great, and Newton put aside his calculations . Six years later a new determination of the size of the earth gave him a new basis foi calculation, and, in an excitement so great that he could hardly see his figures, Newton found that the fall of a stone to the earth and the sweep of the moon in her See also: |