Of the two great philosophers of Greece, Plato and Aristotle, the latter was the one who relied on observation. Raphael's The School of Athens shows the two great philosophers in the center of the painting, surrounded by the other great Greeks, with Plato holding his hand upright as if to indicate, "Look to the perfecti on of the heavens for truth," while Aristotle holds his arm straight out, implying "look around you at what is if you would know the truth." We shall look deeper in Aristotle's ideas below.
Aristotle was born in Stagira (in northern Greece), 384 B.C. He died in Chalcis (on the Aegean island of Euboea, now Ewoia), 322 B.C. Inland from Stagira was the semi-Greek kingdom of Macedon, with which Aristotle's family was closely connected. Aristotle's father, for instance, had been court physician to the Macedonian king Amyntas II. Aristotle lost both parents while a child and was brought up by a friend of the family. He is supposed to have spoken with a lisp and to have been something of a dandy.
At the age of seventeen Aristotle traveled to Athens for a college education and after Plato returned from Syracuse, the young man joined Plato's Academy, where he studied assiduously. Eventually he was to become by far the most renowned of all the pupils of Plato. Plato called him "the intelligence of the school."
When Plato died in 347 B.C., Aristotle left the school. The reason he gave was that he disapproved of the growing emphasis on mathematics and theory in the Academy and the continuing decline in natural philosophy. However, it is possible that he may have been displeased that Plato, on his deathbed, designated his nephew, an undistinguished person, as his successor, passing over the merits of Aristotle. It is also true that Athens and Macedon were enemies at the time and Aristotle may have felt uneasily conscious of being considered pro-Macedonian.
In any case Aristotle found it expedient to set out upon a journey that carried him to various parts of the Greek world, particularly to Asia Minor. While there he married and engaged in the study of biology and natural history, always his chief love.
In 342 B.C. he was called to Macedon. The son of Amyntas II had succeeded to the throne of Macedon as Philip II while Aristotle was at the Academy, and now the king wanted the son of his father's physician back at court. The purpose was to install him as tutor for his fourteen-year-old son, Alexander. Aristotle held this position for several years. Since Alexander was to become Alexander the Great, the conqueror of Persia, we have the spectacle of the greatest soldier of ancient times being tutored by the greatest thinker.
In 336 B.C. Philip II was assassinated and his son succeeded as Alexander III. Alexander had no further time for education so Aristotle left Macedon the next year and went back to Athens while Alexander went on to invade the Persian Empire in a great conquering campaign. Aristotle's nephew, Callisthenes, accompanied Alexander, but Aristotle's influence over his erstwhile pupil was not very great for in 327 B.C. Callisthenes was executed by the increasingly megalomaniac monarch.
Meanwhile, in Athens, Aristotle founded a school of his own, the Lyceum, so called because Aristotle lectured in a hall near the temple to Apollo Lykaios (Apollo, the Wolf-God). It was also called the "peripatetic school" (walk about) because Aristotle, at least on occasion, lectured to students while walking in the school's garden. He also built up a collection of manuscripts a very early example of a "university library." It was this which eventually served as the kernel for the great Library at Alexandria.
The school continued under Aristotle's directorship quite successfully, emphasizing natural philosophy. In 323 B.C., however, the news arrived of the death of Alexander the Great in Babylon. Since Aristotle was well known to have been Alexander's tutor, he feared that an anti Macedonian reaction in Athens might lead to trouble. And, indeed, the accusation of "impiety" was raised. Aristotle had no mind to suffer the fate of Socrates. Saying he would not allow Athens to "sin twice against philosophy" he prudently retired to Chalcis, his mother's hometown, and died there the next year.
Aristotle's lectures were collected into nearly 150 volumes and represent almost a one-man encyclopedia of the knowledge of the times, much of it representing the original thought and observation of Aristotle himself. Nor was it confined entirely to science, for Aristotle dealt with politics, literary criticism, and ethics. Altogether, of the volumes attributed to him, some fifty have survived (not all of which are certainly authentic), a survival record second only to that of Plato. This survival came about through a fortunate chance. Many of his manuscripts were found in a pit in Asia Minor about 80 B.C. by men in the army of the Roman general Sulla. They were then brought to Rome and recopied.
The one field for which Aristotle is not noted is mathematics, but even here he may be credited with a glancing blow, for he is the virtual founder of the systematic study of logic, which is allied to mathematics. He developed, in great and satisfying detail, the art of reasoning from statement to necessary conclusion and thereby demonstrating the validity of a line of thought. His system stood without major change until the nineteenth-century development of symbolic logic by Boole, which converted logic in to a branch of mathematics in form as well as spirit.
Aristotle's most successful scientific writings were those on biology. He was a careful and meticulous observer who was fascinated by the task of classifying animal species and arranging them into hierarchies. He dealt with over five hundred animal species in this way and dissected nearly fifty of them. His mode of classification was reasonable and, in some cases, strikingly modern. He was particularly interested in sea life and observed that the dolphin brought forth its young alive and nourished the fetus by means of a special organ called a placenta. No fish did this, but all mammals did, so Aristotle classed the dolphin with the beasts of the field rather than with the fish of the sea. His successors did not follow his lead, however, and it took two thousand years for biologists to catch up to Aristotle in this respect. It was J. Muller who finally confirmed Aristotle in this respect. Aristotle also studied viviparous sharks, those that bear live young -- but without a mammalian placenta. He also noted the odd ability of the torpedo fish to stun its prey though, of course, he knew nothing of the electric shock with which it managed it. He was also wrong on occasion, as when he denied sexuality in plants. Nineteen centuries were to pass before Alpini was to correct this particular error.
His formation of a hierarchy of living things led him irresistibly toward the idea that animals represented a chain of progressive change, a sort of evolution. Other Greek philosophers groped similarly in this direction. However, barring any knowledge as to the physical mechanism whereby evolutionary changes could be brought about, such theories invariably became mystical. A rational theory of evolution had to await Darwin 2200 years after the time of Aristotle.
Aristotle studied the developing embryo of the chick and the complex stomach of cattle. He decided that no animal had both tusks and horns, and that no single hoofed animal had horns. But his intuition sometimes led him astray. He believed the heart was the center of life and considered the brain merely a cooling organ for the blood.
In physics Aristotle was far less successful than in biology, perhaps because he was too Platonic. He accepted the heavenly spheres of Eudoxus and Callippus and even added further to them, reaching a total of 54. He seemed to think of the spheres as having an actual physical existence whereas Eudoxus probably thought of them as imaginary aids to calculation, as we consider the lines of latitude and longitude we draw on a map. Aristotle also accepted the four elements of Empedocles but restricted them to Earth itself. He suggested a fifth element "aether," of which all the heavens were composed. (We still use phrases such as "ethereal heights" today.)
This line of reasoning led him to agree with the Pythagoreans that Earth and heaven were subjected to two different sets of natural law. On Earth all things were changeable and corrupt, while in the heavens all was permanent and unchanging. On Earth the four elements each had its own place, and motion was an attempt to reach that place. Earth was in the center, water above it, air above that, and fire highest of all the earthly substances. Therefore an object composed largely of earth, such as a rock, would, if suspended in air, fall downward, while bubbles of air trapped under water would move upward. Again rain fell, but fire rose.
It also seemed to Aristotle that the heavier an object was, the more eagerly it would strive to achieve its proper place since the heaviness was the manifestation of its eagerness to return. Hence a heavier object would fall more rapidly than a lighter one. Nineteen centuries later, a reconsideration of this problem by Galileo was to lead to momentous consequences. The motion of heavenly objects, on the other hand, was no attempt to get anywhere. It was a steady, permanent motion, even and circular.
Aristotle, apparently, was not an experimentalist for all that he was a close observer. He observed that rocks fell more quickly than feathers, but he made no attempt to arrange an observation of the falling of rocks of graded weight. Furthermore, neither he nor any other ancient scholar properly appreciated the importance of precise, quantitative measurement. This was not mere perversity on their part, for the state of instrumentation was rudimentary indeed in ancient times and there were few clear methods of making accurate measurements. In particular, they could not measure small intervals of time accurately, a deficiency that was to remain for two thousand years until the time of Huygens.
Aristotle rejected Democritus' atomism, dooming that concept through ancient and medieval times. On the other hand, he accepted the Pythagorean notion of the roundness of Earth, presenting his reasoning in a fashion that remains valid today. The most telling argument was that as one travels north, new stars appear at the northern horizon while old ones disappear at the southern. If Earth were flat, all stars would be equally visible from all points on its surface. It was Aristotle's championing of this view that kept it alive through the darkest days that were to follow.
Aristotle's system of philosophy was never as influential in ancient times as Plato's. Indeed, Aristotle's works may not have been published for some centuries after his death. After the fall of Rome, his work was largely lost to Europe (only Organon, his work on logic, was saved) while Plato's works were, for the most part, retained. However, Aristotle's books survived among the Arabs, who valued them highly.
Christian Europe regained Aristotle from the Arabs, translating his books into Latin in the twelfth and thirteenth centuries. From that time Aristotle replaced Plato as the Philosopher. His views came to be regarded as possessing an almost divine authority, so that if Aristotle said it was so, it was so. By a queer fatality, it almost seemed as though his statements were most accepted when they were most incorrect.
This cannot be blamed on Aristotle, who was himself no believer in blind obedience to authority. Nevertheless, following the era of over-adulation, he became the very symbol of wrongness, and when the Scientific Revolution took place in the sixteenth and seventeenth centuries, its first victories involved the overthrow of Aristotelian physics. In the centuries since, Aristotle has, as a consequence, too often been viewed as an enemy of science, whereas actually he was one of the truly great scientists of all time and even his wrongness was rational. No man should be blamed for the stubborn orthodoxy of those who many centuries later insist they speak in his name.
The Greeks made a decisive choice in favor of the organismic viewpoint of nature. This choice was at least as Greek in spirit as the so-called of the Ionians. Some historians of science have tried desperately to present scientific rationalism as the only genuine exhibition of the Greek spirit. These historians have tried to support their case by claiming the influence of factors, such as religious ideas penetrating Hellas from the eastern shores of the Mediterranean, which were just as foreign to the Greek mind. In fact, long before religious ideas gained significant influence, the greatest of the Greek thinkers settled on the primacy of the organismic view, mainly because they found it to provide the type of intelligibility that best satisfied the aspirations of the Greek mind.
As Greek intellectual development after Plato continued through its phases, its formers, with great unanimity, adhered to organicism. Aristotle is very typical. A resolute critic of Plato's main philosophical construct, the theory of ideas, Aristotle remained nonetheless faithful to the basic tenet of the Socratic program: nature was to be understood as something like man himself -- moving toward goals, striving toward the best possible arrangement, in short, acting like an organism. He was convinced that the universe was supremely a living being both in its entirety and in its parts.
In fact, it is in Aristotle's Physics that one finds the first simultaneous occurrence of the terms microcosmos and megacosmos (macrocosmos), terms which were to serve as the characteristic stamp on every organismic theory about the universe until the very modern times. In the eighth book of the Physics, Aristotle reviewed several objections to a fundamental doctrine of his, the eternity of motion. According to these objections, motion need not always be caused by another motion but could at times be preceded by absolute rest. For proof, one of the arguments refers to the case of living beings, to human consciousness and animal behavior in particular.
...the animal...we say, moves itself; therefore, if an animal is ever in a state of rest, we have thing in which motion can be produced from the thing itself, and not from without. We see nothing like this in the case of inaminate things, which are always set in motion by something else from without: the animal, on the other hand, we say, moves itself; therefore, if an animal es ever in a state of abosolute rest, we have a motionless thing in which motion can be produced from the thing itself, and not from without. Now if this can occur in an animal, why should not the same be true also of the universe as a whole? If it can occur in a small world [microcosmos] it could also occur in a great one [megacosmos].... [Note 1]
The conclusions of this argument were totally contrary to the foundations of Aristotle's system. Nevertheless, all Aristotle found to criticize in this argument, was the conclusion alone and not the organismic analogy on which it rested. Aristotle offers no objection and finds no fault with the general organismic principle that allows one to move without any qualification from the small world of an animal to the large world of the inanimate universe. It was a principle that had to appear to him as basically sound. As a consequence, Aristotle, in general so reluctant to praise the intelligence of his opponents, qualifies the objection based on this principle as one he saw to "present more difficulty than the others" for his doctrine of the eternity of motion. Obviously he realized that the objection had carried the battle to his own grounds.
When faced with objections based manifestly on principles diametrically opposite to his own, Aristotle's phrases betrayed hardly any hesitancy or surprise. Thus in a highly revealing passage of the second book of the Physics Aristotle drew a sharp contrast between the early physics and what physics really ought to be. According to the former, nature does not work for the sake of something or because it is better one way than another; it rather works of necessity, that is, in a regularly repeated pattern of sequences. The necessity and regularity of his predecessors' physics had, however, been dependent on chance, and Aristotle eagerly seized on this obvious inconsistency. Chance, Aristotle argued, does not repeat things in a regular fashion. Regularity can be assigned only to purposeful action, which, as he contended, always works for an end and originates from the particular nature that is acting. It was at this point that Aristotle reaffirmed the basic goal of Socrates' arguments: the restoration of unity between man and nature in an organic whole. The declaration of a perfect parallelism between the way man acts and the manner in which nature operates could not be more explicit:
As in human operations, so in natural processes; and as in processes, so in human operations (unless someting interferes). Human operations are for an end, hence natural processes are so too.". . [Note 2]
To Aristotle, the "physical method," as he referred to Democritus' approach to nature (mechanism), failed in this most essential aspect because it tried to explain things and processes by decomposing them into their parts leaving aside the aspect of their wholeness. But, as Aristotle insisted time and again, basic information about objects, living and nonliving alike, could be obtained only by a method that concentrated on the wholeness in things and processes. Whether an animal or a couch is to be explained, the investigation should take its start from a definition of the whole, a definition that will shed light on the role of organs or parts played in the whole.
For it is not enough to say what are the stuffs out of which an animal is formed, to state, for instance, that it is made of fire or earth -- if we were discussing a couch or the like, we should try to determine its form rather than its matter (e.g. bronze or wood), or if not, we should give the matter of the whole. ... For the formal nature is of greater importance than the material nature..[Note 3]
By stressing the priority of the whole over the parts instead of treating the whole merely as a sum of the parts, Aristotle meant, in fact, that
For the formal nature is of greater importance than the material nature..[Note 4]
Or, in other words, the study of nature is to be dominated by the idea expressing the coordination of parts in the whole, which is the principle of organism. Believing that animate and inanimate beings alike have coordinated parts, Aristotle lowered the dividing wall between the two domains to such an extent that comparisons between the living and non-living became the most naturally used device in his writings on natural science. Speaking of the merits of the study of animals, Aristotle was highly elated about the teleology displayed in the animal world and concluded:
...the true object of architecture is not bricks, mortar, or timber, but the house; and so the principal object of natural philosophy is not the material elements, but their composition, and the totality of the substance, independently of which they have no existence..[Note 5]
Although modern natural science is reluctant to speak in the same breath of bricks and animals, Aristotle saw a basic justification for doing so in the wholeness allegedly present in any object. Of this holistic approach to the study of nature Aristotle stated in the most categorical terms that it is precisely there that the "physical" method and the "true" investigation of nature part ways. When refuting the opinions of Anaximenes, Anaxagoras, and Democritus on the flatness and motion of Earth, Aristotle tells us
In general, our quarrel with those who speak of movements in this way cannot be confined to the parts; it concerns the whole universe.. [Note 4]
Once the wholeness of an object is grasped, said Aristotle, its properties and parts will readily reveal themselves. The golden key to the wholeness or nature of a thing consists in detecting its spontaneous motion. Implicit in this spontaneity is the goal of the motion, which in turn lays bare the nature of the thing in motion.
All the things mentioned [things that exist by nature] plainly differ from things which are not constituted by nature. For each of them has within itself a principle of motion and of stationariness (in respect place, or of growth and decrease, or by way of alteration).7
As opposed to products of crafts, the beings "constituted" or formed by nature, animals, plants, earth, fire, air, and water have within themselves the beginning of movement:
All natural bodies and magnitudes we hold to be, as such, capable of locomotion; for nature, we say, is their principle of movement.8
Formed by nature they move toward their respective ends, and the end of such a natural motion is identical with the purpose for which the thing exists.
...whenever there is plainly some final end, to which a motion tends should nothing stand in the way, we always say that the one is for the sake of the other....9
Motion, nature, organism, and teleology, therefore, were simply different aspects of one basic viewpoint, in which locomotion, qualitative change, the growth of the living, and the healing of the sick were treated on the same footing. Having rejected the possibility of a regress to infinity, Aristotle thought he could readily show that if there is anything at all to exist, its motion, the primordial motion, should be a natural one. On the other hand, if the first motion
was natural, careful consideration will show that there was already a world.10
This statement, directed against the notion of atoms whirling in space in every direction before the present configuration of things came to take shape, should forcefully intimate the multitude and sweep of conclusions that Aristotle derived from the concept of natural motion. After all, his universe was a "huge nature" of which all parts were moving, striving, and yearning toward their respective ends.
In fact, Aristotle needed only the distinction between the two types of natural motion, circular and straight, to be ready to tell us what it is like to be a cosmos.
Aristotle's wizardry in squeezing out a long list of conclusions from one basic proposition is astonishing but hardly convincing. He presents his argument that the primary body, or ether, cannot be infinitely extended in no less than six variations. The great effort expended was superfluous, however, for as it turned out, the "nature" of any of the four elements could provide for Aristotle a specious argument against the infinity of the universe. Characteristically, according to him, one of the reasons f or discarding the concept of an infinite number of atoms moving in infinite space was that in infinite space no natural motion can take place, because in infinite space no place or point can be assigned unambiguously as the endpoint of any object's motion.
Since the nature of a body determines the pattern or the direction of its motion, it follows that all Earth would move of itself toward the same place, which is the center of the universe, and all fire would always move upward toward the circumference of the world. The weighty problem of the multiplicity of worlds is thereby readily "solved" in a reasoning, the parts of which are as tightly interlocking as the parts of any organism:
For either we must refuse to admit the identical nature of the simple bodies in the various universes, or, admitting this, we must make the center and the extremity one as suggested. This being so, it follows that there cannot be more worlds than one.12
Aristotle took pains to emphasize that distances between worlds, however large, could change the nature of things and their natural orientations. In other words quantitative considerations cannot negate the conclusions derived from the analysis of the behavior of an organism. Now if the world is an immense but finite and unique organism, it is only natural that all matter available in the universe should be coordinated to that "one, and unique, and complete" system,13 or else nature would have produced something to no purpose, which is unacceptable. Therefore no places, nor void, nor time exist beyond the limits of the universe, for the existence of any one of these would presuppose the existence of a natural body distinct from the unique cosmos.
The concept of "nature" secures for the world not only its uniqueness and finiteness, but also a life of perfection. The highest degree of life in the cosmos resides in the sphere of the ether:
...this motion, being perfect, contains those imperfect motions which have a limit and a cessation, having itself no beginning or end, but unceasing through the infinity of time. ... Further, it is unaffected by any mortal discomfort, and, in addition, effortless....[Note 14]
... as should be with a uniform circular motion. But for life to be perfect, it must contain whatever "is present in the lowest stage of animal life." Therefore, like animals, the heavens must have front and back, left and right, above and below. The three-dimensionality of space is, in fact, just a corollary of the motion of living bodies, that is, bodies that have the principle of motion in themselves. The vertical direction is a consequence of growth that is from above, and the two horizontal directions are the results of locomotion that is from right to left (the right being the more noble side) and of the sensations that are from the front. Now since...
the heaven is animate and possesses a principle of movement, clearly the heaven must also exhibit above and below, right and left. ... We must think of the world as of something in which right differs from left in shape as well as in other respects, which subsequently is included in a sphere. [Note 15]
The direction of the revolution of the skies shows, therefore, that the celestial hemisphere seen in the northern latitudes is really the lower half of the universe, the southern pole of the skies being the top of the cosmos. Hence, those who live in the southern regions are
in the upper hemisphere and to the right, while we are in the lower and to the left.1 [Note 16]
An absolutely valid coordinate system is indeed one of the consequences of viewing the world an as organism. What is more, the three perpendicular directions, being corollaries of life and motion, are not even of the same "dignity." The vertical direction is the most important, since the growth that manifests it can be found in every living thing, whereas the horizontal directions are of lesser rank because they cannot be discerned as basic direction of motion or growth in every living thing, such as a plant.
In the Aristotelian system the world taken as an organism revealed its features with alarming ease once its basic striving or nature had been defined. With a tour de force almost unparalleled in the history of science Aristotle showed in a single breath-taking page of On the Heavens [Note 17] why the world should consist of different parts and why these parts should be the very same parts we actually observe in the world. His seductive, a priori account of the main features of the universe reveals in its true nature the liberties that an organismic type of physics unavoidably takes in its approach to nature. Some details are especially worth considering if one is to obtain a close-up view of the dubious procedures that physical science is forced to adopt when the universe is viewed as an organism and when motion is believed to unravel the nature of things with dazzling ease. Thus Aristotle declared that the outermost shell of the cosmos is by necessity spherical, for it is made of divine substance and whatever is divine must be circular. It must also be perfectly smooth, for otherwise there would be "places" beyond the limiting circle and that would be tantamount to a contradiction in terms. The direction of the revolution of the heavens is not haphazard either, because "... nothing which concerns the eternal can be a matter of chance or spontaneity...." [Note 18] In other words the actual direction of this revolution should be accepted as a right to left movement, for right is superior to left. But can the fact be an explanation of the fact itself? Very much so, runs Aristotle's answer, "Supposing that nature is ordered in the best way possible, this may stand as the reason of the fact mentioned." [Note 19]
The invariable speed of the heavenly revolution too is but an aspect of its eternal nature. Since a decrease of speed is a loss of power, Aristotle argued that such a loss could not take place in the heavens composed of the ether, a substance which by definition was not subject to decay of any sort. On a similar basis is decided the question of the composition of the stars too. If there is a body whose nature is to move in a circle, it is only logical to suppose, the argument runs, that the stars, which have a circular motion, are made of that substance, which again by definition is the ether. On such ground one can also readily discern, so Aristotle believed, whether the stars move round the heavens in the manner of progression observable in living beings. To resolve this question so strongly conditioned by the organismic approach, Aristotle, of course, had to resort to organismic analogies to clinch his proof. If the stars moved in such a way, he argued, nature would have provided them with organs of motion closely resembling those of the animals. But nature, which provides so generously for even the lower types of being, seems to have made the stars as different as possible from creatures that are endowed with various organs of motion. Thus the stars are spherical because a sphere, which is best suited for motion in the same place, is the least suited to progression
For while of all shapes the sphere is the most convenient for movement in one place, making possible, as it does, the swiftest and most self-contained motion, for forward movement it is the most unsuitable least of all resembling shapes which are self-moved, in that it has no dependent or projecting part, as a rectiliinear figure has, and is in fact as far as possible removed in shape from ambulatory bodies. [Note 20]
Not every motion in the heavens, however, has the apparent simplicity and uniformity of the stars. It was in fact impossible to avoid facing the question of fitting the complicated motion of planets into the divine simplicity of the heavens. In an organismic explanation of the world this gravest of all questions that ancient astronomers grappled with presents no difficulty at all. Aristotle warned:
We think of the stars as mere bodies and as units with a serial order indeed but entirely inanimate; but we should rather conceive them as enjoying life and action. On this view the facts cease to appear surprising. [Note 21]
Thus Aristotle, to explain the irregularities of planetary motions, fell back on one of his stock illustrative examples: the various phases in the progress of a sick organism toward health. The closer one is to health, goes the narrative, the fewer steps are needed to reach it. One individual may be healthy without any exercise, another may need only a little walking, a third might have to exercise strenuously, and a fourth may simply never become healthy despite tremendous exertions. Now, since the case of planets is taken without any second thought to be analogous to that of animals and plants striving for health, it is easy to see, contended Aristotle, that the farther a planet is from the sphere of the stars, the region of perfect life, the more cumbersome would be its motion. Clearly, if difficult problems could be solved with such ease, one could hardly feel doubt about the merits of the solution.
However, one must admit that Aristotle was extremely consistent in claiming that the errors of his predecessors on Earth's immobility, place, and shape were due to their ignorance of the concept of natural motion. In other words, he took them to task for not approaching the problems of geophysics from an organismic viewpoint. This was particularly true of the Pythagoreans, who preferred mathematical notions and geometrical patterns to organismic analogies. For them Earth was revolving around the central fire, the function of which was, in their belief, to protect the most noble part of the cosmos: its geometrical center. But Aristotle quickly retorted that
... it is better to conceive of the cae of the whole heaven as analogous to that of animals, in which the center [or heart] of the animal and that of the body are different. [Note 22]
Therefore he concluded on a markedly triumphant note that it is not the mathematical center of the world that should hold the place of honor, but rather its true center. Where this true center might be, however, can be established in the framework of an organismic physics only through an analysis based on the natural motion of bodies. On such grounds, an abstract geometrical point obviously could not compete with the massive body of Earth for the central position in the universe. For could an abstract point display "strivings" and "affections," those supreme signs of intelligibility?
The same attitude, emphasizing invariably the primacy of organismic concepts and their primordial intelligibility, dominated Aristotle's refutation of the geophysical views of the other pre-Socratic philosophers. Aristotle claimed that those who like Thales let Earth rest on water evidently did not understand the nature of water, which is not supposed to carry any heavier body such as Earth. Those who stated that a huge vortex keeps Earth in the middle failed to see, he remarked, that if there is a motion by constraint, there should be a prior natural motion. Those who invoked the principle of indifference to account for the immobility of Earth did not fare much better in Aristotle's eyes. They reasoned that an object situated at the center and related equally to the extremes in every direction can have no impulse to move in any specific direction. In fact, they compared the situation of such an object with that of a man violently but equally hungry and thirsty, standing at the same distance from food and drink and unable to decide in which direction to move.
Aristotle, however, rejected this apparently so "organismic" reasoning on the ground that it is not organismic enough. A consistently organismic explanation, he warned, cannot ignore the basic strivings of all types of matter. True, he admitted, a heavy body, such as stone, has such a completely natural indifference to moving toward the periphery. Such is not the case, however, with the light bodies, air and fire, which show an innate tendency to move toward the periphery of the universe, all whose parts are equidistant from Earth. Therefore, concluded Aristotle, Earth's rest at the center of the universe should be taken as a consequence of Earth's nature and not of its position there.
Aristotle could not leave this subject without making a remark that brings out vividly how the intuitive, all-embracing "intelligibility" of the organismic approach can deprive science of the best source of understanding, the benefits of judicious observation. One condition for making such an observation is clearly one's ability to concentrate his attention on the thing or phenomenon to be observed -- in other words, to isolate it from anything merely accidental or circumstantial. The organismic approach to nature has no patience with such a methodical isolation of inanimate things from their surroundings and from one another. For as long as the concept of organism reigns supreme in physical science, things in nature are viewed as organically interconnected, and the notion of an isolated part becomes basically deficient. His opponents, Aristotle claimed, kept considering only isolated aspects of an organic whole and this he found an inadmissible procedure. To quote his harsh strictures: it is
absurd to look for a reason why Earth remains at the center and not f...
Prof. Fred L. Wilson
Rochester Institute of Technology
Science and Human Values
Aristotle (2)
This was, however, a hasty recrimination that could quickly boomerang. For in the same context Aristotle by his own procedure unwittingly illustrated the disastrous consequence of the application of the organismic method to physical investigation: the role to be played by observational evidence becomes secondary in establishing scientific conclusions. In arguing the cause of geocentrism, Aristotle referred of course to the absence of any observable change in the relative position of the stars. Yet, one feels that his reference to the data of actual observation does not represent the principal part of the proof in an organismic context: observation at best underlines what has already been established on more general grounds.
No different is the case of Earth's shape as discussed by Aristotle. The keynote of his argument is again the same old organismic precept: Earth has to be spherical because only a spherical shape can result when pieces of matter have an innate tendency to move from every direction toward the same point. To some extent Aristotle along with earlier natural philosophers was willing to view this process as a sort of generation of Earth. But whereas they attributed it to external and mechanical compulsion, Aristotle was quick to stress "the true statement that this takes place because it is the nature of whatever has weight to move towards the center." [Note 24] Astronomical observations of the eclipses of the moon and of the different constellations visible from various latitudes serve as further proof of the sphericity of Earth, but not as the proof. The latter always rests on an almost introspective grasp of the alleged innate strivings of Earth as a natural body.
From the shape and general characteristics of Earth, Aristotle proceeded to a discussion of its composition, and this, like any other part of his physical system, rested on his views of motion and nature. Earth, or more precisely, the sublunary world, must be composed, according to him, of simple bodies, because there are simple motions in that region. "Nature," he said, "is a cause of movement in the thing itself," [Note 25]which means that every natural body must have its own proper motion, striving, if not volition. Now, since motions are either simple or composite and since simple motions belong to simple bodies, "it clearly follows that certain simple bodies must exist. For there are simple motions." [Note 26]The number of simple bodies or elements then is obviously determined by the number of simple motions, a number that cannot be infinite because "the directions of movement are limited to two and the places also are limited." [Note 27] Although this theory strictly speaking calls for only two elements, earth and fire, Aristotle made place for four on the ground that nature, which likes to level out excesses and prefers graduated changes, provides the other two elements, water and air, for intermediate bodies. The decisive role of organismic considerations in such a reasoning hardly needs to be pointed out.
The four elements can change one into another, and the place where such transformations take place -- mainly under the influence of the variations in the sun's path -- is the sublunary world, the realm of the Aristotelian meteorology. Usually dismissed as the least valuable part of Aristotle's studies in natural science, it illustrates better than anything else, however, the totally self-defeating consequences of the attempt to achieve a sound understanding of the workings of inanimate nature on the basis of an organismic concept of the universe. The part of natural science discussed by Aristotle in his Meteorologica roughly corresponds to what at present is called atmospheric physics and geophysics. It deals with the part of the physical universe immediately surrounding man, abounding in easily observable (though at times very complicated) phenomena that hardly betray the characteristics of organismic processes. Yet Aristotle remained faithful as always to his organismic viewpoint and embarked on a fanciful and highly arbitrary account of a host of phenomena that range from the Milky Way to the cavities of Earth.
What makes Aristotle's discussions in the Meteorologica so glaringly arbitrary is the resolute determination to explain the features of an inanimate part of the world in the terms and categories of life processes. To the Meteorologica pertain, Aristotle stated, "all the affections we may call common to air and water and the kinds and parts of Earth and the affections of its parts." [Note 28] Accordingly these affections are looked for in every nook and cranny of nature, in the atmospheric turbulences as well as in those occurring within Earth. This should hardly be the cause of any surprise. For if a method is devised to find affections (strivings) characteristic of living organisms, its exclusive use will succeed in causing such affections to be seen even where they are patently absent. Even when used judiciously, such a method will help one discover only affections and little else. Judiciousness is hardly the forte of those students of physics who conceive of the inanimate universe as a living organism.
On the contrary, undue preoccupation with the organismic viewpoint is apt to create a state of mind that is instinctively driven to sweeping generalizations. Of this a manifest example is the author of the Meteorologica, who does not tire of repeating the precept of an ironclad methodological unity in all branches of the study of nature: there can be no difference in the method with which comets, winds, rivers, earthquakes, plants, and animals are to be investigat ed. It is no surprise, therefore, that in comparing Aristotle's attitude in this matter with that of the pre-Socratic Ionian Philosophers, such a careful scholar as F. Solmsen could find hardly any precedent for the single-mindedness with which Aristotle organized the subject. [Note 29] The often decried rigid monism of the Ionians seems flexible indeed when contrasted to the onrush of inferences dominating the Meteorologica from beginning to end. It is not at all unreasonable to assume, as Solmsen does, that Aristotle considered it dilettantish, or beneath the calling of a philosopher, to admit more than one explanatory principle. There is, however, hardly a place for several viewpoints aiming at a balanced judgment when one attacks a topic "with a will." Therein lies the chief characteristic of all efforts, ancient and recent alike that try to discourse on inanimate nature in terms of purposeful inclinations, in strict analogy to living organisms.
Aristotle stated that the Meteorologica dealt with the material and efficient causes and named the sun's rays as the efficient cause of whatever happens between the moon and the depths of Earth. In connection with the production of rain, hail, and snow, Aristotle even described how the heating caused by the sun's rays sets in motion the circulation of huge masses of air and moisture in the atmosphere. He also spoke of the cooling and condensation of vapor at higher elevations and of the evaporation of water heated by the sun's rays. "So we get a circular process that follows the course of the sun.... We must think of it as a river, flowing up and down in a circle and made up partly of air, partly of water." [Note 30] But this great vision of atmospheric mechanism remained undeveloped. The chief efficient cause turns out to be a rather remote agent that merely releases, so to speak, the "actors" of a complex interplay. The "actors" are natures, dry and moist exhalations, produced by Earth, which is described as a huge animal that grows, digests, and produces gaseous residues. The physical factor driving this process is, as in animals, heat, and Aristotle's train of thought moved most naturally from the hot ashes and lye in Earth to the hot bellies and excreta of animals. Thus just as the nature of ether could yield all the necessary answers in the superlunary world, so do these dry and moist excreta or exhalations of Earth supply the solution to almost anything to be found above and below Earth's surface.
Among the atmospheric phenomena that are said by Aristotle to consist of dry exhalations are the "shooting stars." Speaking in the best matter-of-fact style, he stated that the motion of planets sets afire the dry exhalation present in the upper atmosphere, and the burning material, or shooting star, takes on a shape or course that differs, he added in a scientific-sounding tone, "according to the disposition and quantity of the combustible material." [Note 31] Such vague quantitative cadenzas, however, should not mislead anyone as to the true nature of the procedure. An organismic type of physics that relies so heavily on insights, intuitions, and aperçus will impart almost of necessity to the student of nature a self-assurance that hardly knows limits. The result is more often than not a flight of fancy in which the only element smacking of genuine science is the choice of words and phrases.
Thus in the Meteorologica firelike appearances in the night sky, "torches," "goats," and what not are accounted for with an ease that betrays no doubt and acknowledges no difficulties. In the same vein we are told that thunderbolts simply consisted of hot and dry exhalations of Earth, compressed by surrounding cold air masses and pressed downward with great velocity. Through their speedy motion across the atmosphere these compressed dry exhalations became fiery (lightning), and when they collided with other clouds, violent sounds (thunderclaps) were produced. The bloodred glow of the evening skies was also reduced to the behavior of dry exhalations as were the comets that Aristotle identified as slowly burning shooting stars. Thus the appearance of comets necessarily indicated for him the rise of strong winds, since the latter were made of the same "all-purpose" substance too. Many and dense comets were therefore signs of a dry and windy year.
To what unsuspecting extremes organismic physics can carry the most penetrating mind can nowhere be better seen than in Aristotle's explanation of the origin of the huge meteorite that fell at Aegosotami in 467 B. C. and that was remembered with awe and puzzlement for a long time thereafter in ancient Greece. As stones could not originate outside Earth's sphere in Aristotle's system, he flatly stated that the huge stone "had been carried up by a wind and fell down in daytime -- then too a comet happened to have appeared in the west." [Note 32] The explanation of the Milky Way rushed onward with the same confidence. For if the motion of a planet or of a star could set aglow the dry exhalations and produce shooting stars and comets, why should the great constellations in the belt of the Milky Way not be able to produce the same effect on an even larger scale?
Next to the dry and moist exhalations the cold and the hot as distinct natures played a similarly important part in Aristotle's Meteorologica and again involved him in a long series of gratuitous statements. The cold and hot, being contraries, should, according to Aristotle's general explanation of the behavior of contraries, have speeded up reactions depending on their presence. Thus Aristotle was impelled to state that "the fact that the water has previously been warmed contributes to its freezing quickly: for so it cools sooner." Unlikely as such a "fact" is, Aristotle found nothing strange in it. What is more he reported in all seriousness that many people "when they want to cool hot water quickly begin by putting it in the sun." Apparently he found this "law" of physics so important that he even mentioned the custom of the people of Pontus who when fishing in wintertime poured hot water around their reeds "that it may freeze the quicker, for they use the ice like lead to fix the reeds." [Note 33]
Since the main goal of organismic physics is to find out the "volitions" of bodies and objects, it is only natural that what Aristotle wanted to know about winds, windy vapors, rivers, and sea was their nature or "strivings." He thus engaged in a relentless search for distinct natures in the physical world (inanimate "individuals," one might almost say) and ended up regarding air as something essentially different from wind. He did this in the most categorical manner. "It is absurd," he said, "that this air that surrounds us should become wind when in motion, whatever be the source of its motion." [Note 34] It was rather "wind that sets the air in motion." [Note 35] To crown the comedy Aristotle was not loath to heap sarcasm on those who, like Hippocrates, "define wind as a motion of the air." The rest of Aristotle's comment on such a position deserves to be quoted in full:
Hence some, wishing to say a clever thing, assert that all the winds are one wind, because the air that moves is in fact all of it one and the same; they maintain that the winds appear to differ owing to the region from which the air may happen to flow on each occasion, but really do not differ at all. This is just like thinking that all rivers are one and the same river, and the ordinary unscientific view is better than a scientific theory like this. [Note 36]At any rate, this was not the only time that organismic physics had to side with popular beliefs and reject reasonable views. Aristotle, caught in the vicious circle of his organismic physics, at times had to ignore the obvious and state for instance that the dry exhalation from Earth "is the source and origin of all winds." [Note 37] In the organismic framework a motion like that of the winds must proceed from a specific entity or nature. Therefore Aristotle had no alternative but to conclude: "In its generation and origin wind plainly derives from Earth" [Note 38] . To solve difficulties arising from such definition of the wind's substance, Aristotle fell back on analogy, a procedure particularly suited to an organismic type of explanation. That small, almost imperceptible volumes of dry exhalations escaping from the ground could produce violent winds was as natural for Aristotle as was the case of many small creeks uniting to form a mighty river. "The case of winds," he stated, "is like that of rivers." [Note 39] This analogy "explained" for him why winds were allegedly far removed from marshy regions that were abundant sources of exhalation: springs too grew into rivers only after flowing a considerable distance. On the strength of such analogies Aristotle concluded that just as the various rivers were not the same but each had its own distinct nature, so regional winds too had distinct individualities.
In a similar fashion Aristotle raised the differences between seawater and freshwater into distinctions between substances. He assigned sweetness to the nature of water originating from springs, and from this he concluded that the sea could neither be the origin nor form the main bulk of water on Earth. Were it otherwise, rivers too would be salty. In Aristotle's eyes there was, however, an even more basic reason for stating a sharp qualitative difference between seawater and freshwater. The waters on Earth, he observed, either flow or are stationary. The stationary waters are in turn either mere collections of waters left standing or come from artificial sources such as wells. This specious classification, moreover, became firm ground upon which to base the statement that since natural standing water from springs was never found on a scale comparable to the large bulk of seawater, the seawater must therefore be essentially different from ordinary water. [Note 40]
Concerning the origin of the sea, the dry exhalation again came to the rescue. This time it was described as an "undigested residue" of that giant, growing entity, Earth. Mixing with water, this undigested residue or "earthy stuff" produced the salinity of seawater. Such mixture revealed to Aristotle, however, an organismic interplay or tension between heavy saltwater and fresh drinking water. The latter, said Aristotle, when carried by rivers into the sea spread thin on the surface of the sea and quickly evaporated, whereas the heavy saltwater filled the whole seabed, which in reality would be the natural place of the true (non-salty) water. For Aristotle all this was strictly equivalent to an organismic process, and he identified it with the combustion of food in animal bodies. [Note 41]
The role played in Aristotelian physics by the various dry and moist exhalations came to a climax in the production of earthquakes. That exhalations (winds) could cause great upheavals in the crust of Earth was argued from the fact that winds were swift, could move through bodies, and thereby had properties of a physical agent capable of exerting a major motive force. The way these exhalations touched off earthquakes was explained by rather crude organismic analogies. "We must think of an earthquake," warned Aristotle, "as something like the tremor that often runs through the body after passing water as the wind returns inwards from without in one volume." [Note 42] Their violence was illustrated for Aristotle by a simile that could not be more biological. Tetanus and spasm, he said, were caused by "winds" within the body; yet they were at times so violent that even the united efforts of many men were often not enough to subdue some patients. "We must suppose," went the stereotype conclusion of organismic physics, "that (to compare great things with small) what happens in Earth is just like that." [Note 43] That earthquakes did not die out suddenly was also explained by Aristotle in the same vein: the throbbing in the human body do "not cease suddenly or quickly, but by degrees according as the affection passes off." [Note 44]
Whatever observations Aristotle could have gathered of earthquakes, they are rendered completely useless by his arbitrary ideas on how these exhalations should act. In a bewildering set of statements Aristotle connected earthquakes with eclipses, with midnight and noon, with spring and fall, and even with long, drawn-out clouds. He was fully confident that a special calm preceded every earthquake, that earthquakes were always local, that they did not occur in the middle of the ocean but only close to the shores. Such conclusions, he stated, followed from the theory that "has been verified by actual observation in many places." [Note 45] This statement, needless to say, has little to commend itself. It was mainly luck that the organismic approach and biological comparisons on occasion came reasonably near to the actual course of events.
One such fortunate remark concerned the changes in the respective positions of dry land, rivers, and oceans. Thus from the slow rate of transformation in animal bodies, Aristotle concluded that the processes causing the shifts of the Nile valley were of an almost imperceptible slowness. Yet, he was only too eager to recall twice in the same context the allegedly vitalistic roots of such processes. Changes on the surface of Earth were due to the fact, he stated, that "the interior of Earth grows and decays like the bodies of animals and plants," although "the whole vital process of Earth" took place at such a slow rate that a lifetime was not enough to observe the effects of this continuous transformation of Earth. [Note 46]
Discussions that are free of preoccupations with the nature and affections of organic bodies, or which are not amplified by references to animal behavior, are the exception in Aristotle's organismic synthesis of the physical world. One of these few exceptions is his account of atmospheric phenomena connected with the reflection and refraction of light rays, such as rainbows, halos. Consequently, the related observations are less colored and distorted by references to preconceived patterns of organismic behavior. As a rule, observations are allowed to play but a rather subordinate role in a physical study that views the world as an organism. Furthermore, the principle that every spontaneous and regularly recurring motion implies the existence of a specific nature or substance, multiplies the number of essentially distinct natures. This in turn unavoidably hampers efforts to recognize basic features common to them. Phenomena that are only gradations on the same scale, hot and cold, for example, will therefore be taken as distinct entities. For the same reason standing and flowing waters will be put in basically different categories, just as standing and moving air (wind), circle and straight line, flesh and bone are classed in the Aristotelian science as basically different entities.
It was also Aristotle's preoccupation with primary principles harking back to organismic considerations that led him to conclude that stars and the sun were not hot and that their white glow had nothing to do with fire. Yet, as Theophrastus remarked, Aristotle could easily have observed what had already been noted long before him, namely, that objects which glow white are hotter than those which glow red. [Note 47] Had Aristotle been less engrossed with general organismic principles, he could have anticipated the sagacious remark of his successor at the Academy, Theophrastus, who certainly did not refer to a new fact in arguing that fire, because of its invariable need of some combustible substance, could not be a primary element. [Note 48] Nor had the author of Pneumatics, Hero of Alexandria, to resort four centuries later to novel discoveries to restate the obvious, the identity of wind and air. All he needed was a sober reverence for facts and some measure of freedom from preconceived tenets.
Since an example of organismic behavior easily lends itself to a quick, intuitive grasp by the human observer, organismic physics such as Aristotle's is likely to be given to hasty generalizations. Time and again one encounters the almost stereotyped phrase when Aristotle takes up a new topic: "Let us recall our fundamental principle and then explain our views." [Note 49] The result is that observations that do not fit in the hastily erected framework are brushed aside or not weighed in their true significance. It was mere capriciousness on Aristotle's part to write that "it is actually observable that winds originate in marshy districts of Earth and they do not seem to blow above the level of the highest mountains." [Note 50] As a matter of fact, Aristotle, in his systematization of the physical world, lives up rather poorly to his definition of the good investigator who, as he said, "must be alive to the objections inherent in the genus of his subject, an awareness which is the result of having studied all its differentiae." [Note 51] Ironically enough his speedy generalizations led him into the very pitfall against which he warned so eloquently: "A small initial deviation from the truth multiplies itself ten-thousandfold as the argument proceeds." [Note 52]
The organismic method, apparently secure in its basic assertions, easily produces in the investigator an attitude that Aristotle so severely deplored in others and that he characterized as "excessive simplemindedness or excessive zeal." [Note 53] Aristotle was quick to observe "the great difference which exists between those whose researches are based on the phenomenon of nature and those who inquire by a dialectical method." In the same breath he chastized "as men of narrow views" all those who indulged "in long discussion without taking the facts into account." [Note 54] Yet, it escaped him that it was the organismic method that made him commit the same error in physics. For only the uncritical reliance on an intuitive grasp of things and processes can acquiesce in the Aristotelian advice about phenomena that are not observable: "We consider a satisfactory explanation of phenomena inaccessible to observation to have been given when our account of them is free from impossibilities." [Note 55] Thus, believing himself to be in the possession of the only true method for handling any eventuality, observable or non-observable, that might arise in scientific investigation, Aristotle was daring enough to state quite a few things about admittedly unobservable phenomena as the following passage shows: "The winter in the north is windless and calm; that is in the north itself; but the breeze, that blows from there so gently as to escape observation, becomes a great wind as it passes on." [Note 56]
In Aristotle's On the Heavens and Meteorologica there is hardly a word about phenomena defying solution, and when he voiced puzzlement or caution it was mainly lip service. True, we hear him state in the opening pages of the Meteorologica that of the phenomena to be discussed "some puzzle us, while others admit of explanation in some degree." [Note 57] But in the tortuous mental labyrinths of this work there is hardly a conclusion striking a note of reservation. Aristotle did not even flinch when he flatly told his readers that no one could live beyond the tropics, that the shape of the polar regions resembled a tambourine, and that imaginary lines connecting those regions to the center of Earth cut out a drum-shaped figure.
Facts obviously contrary to his conclusions were grandly talked away, as, for instance the case of winds that happen to blow while an earthquake is taking place. "It is true that some [earthquakes] take place when a wind is blowing, but this presents no difficulty.... Only these earthquakes are less severe because their source and cause is divided." [Note 58] Clearly the escape was sought in a quick distinction for which neither the theory nor the facts provide any basis. The criticism Aristotle leveled at his opponents applied, therefore, wholly to his organismic physics: "They have a wrong conception of primary principles and try to bring everything into line with hard and fast theories." [Note 59] For all too often in handling facts, or rather, in not handling them, Aristotle became guilty of the weakness he found in earlier physicists: "Out of affection for their fixed ideas these men behave like speakers defending a thesis in debate: they stand on the truth of their premises against all the facts, not admitting that there are premises which ought to be criticized in the light of their consequences, and in particular of the final result of all." [Note 60]
The final result proved indeed to be wide of the mark. This was all the more regrettable because even in the field of physics Aristotle at times played the keen observer that prompted Darwin's famous comment on Aristotle, the biologist: "I had not the most remote notion what a wonderful man he was. Linnaeus and Cuvier have been my two gods, though in very different ways, but they were mere schoolboys to old Aristotle." [Note 61] Thus Aristotle, referring to his experiments, stated correctly that not only saltwater but wine and other fluids too, when condensed after evaporation, yield pure water. With regard to the respective weights of saltwater and freshwater he recalled the fate of heavily loaded ships that sank when moved from the sea into the river's estuary. He also noticed that the star in the thigh of the Dog shows a tail when one glances at it, a remark that is explained only in the light of the not-so-old knowledge that the peripheral parts of the retina are more sensitive to illumination.
In spite of such bright details Aristotle's organismic physics was to prove "worthless and misleading from beginning to end." Yet, E. I. Whittaker, the author of this devastating phrase, [Note 62] was neither an anti-Aristotelian nor was he surpassed by many in his understanding of present and past physics. For his statement Whittaker did not claim originality. Many before him took a similar stance and voiced at the same time their appreciation for what was lasting in Aristotle's thought. What then did Aristotle's physics lack that could have prevented it from becoming a world-picture that steadily moved away from reality with every step and resulted ultimately in an exercise in names and words? It is only highly ironical that a philosophical system stressing so much the world of perceptions as the source of ordered knowledge was to produce a physics where the facts were to fit into a preconceived pattern which could not permit a detached look at the nuances of facts without crumbling as a whole. Being a projection of man's nature into the external world, the organismic physics as developed by Aristotle's physics is not a depersonalized analysis of the world but rather a subjective penetration of nature. Its parameters are those of the realm of human volition: natural, unnatural, violent, or restful. Its scope is not to find the correlation of things, but to achieve an intuitive insight into the nature of things, into their alleged strivings and affections. This is why in an organismic physics there is no proper place for mathematics, measurement, or experiments; and quantitative results can never negate the qualitative conclusions. Not that the real, movable, and moving bodies could not be, according to Aristotle, the objects of mathematics, but mathematics is supposed to study them only in abstraction from movement. For to quantize and measure a movement -- this fundamental expression of the nature of things -- would have amounted in Aristotle's view to dissecting both movement and the nature underlying it. Could a "nature," however, be cut to pieces in any meaningful way when it stood by definition for an indivisible whole?
Just as mathematics, according to the Peripatetic dictum, cannot study the nature of movement but only abstractions, conversely, "no abstraction can be studied by Natural Science because whatever nature makes, she makes to serve some purpose." [Note 63] This is why a quantitative study of the elements is rejected. [Note 64] This is why Aristotle could oppose the true center of the universe to its mathematical center. [Note 65] It was for the same reason that his few arguments taken from geometry were exploited in support of his organismic views, as, for instance, when the sphericity of the heavens and stars and their motion was discussed and contrasted to the shape of animals. It was on the same account that Aristotle erected a rigid distinction between mathematicians and natural scientists, or between astronomy and physics. This is why Aristotelian physics, in contrast to geometry, which tries to limit the number of its axioms, results in defining natures without end in order to explain all nuances of motions.
It is because of this that in organismic physics not all movements are comparable and that "a circle and a straight line are not comparable, so that the motions which correspond to them will not be comparable either." [Note 66] This is why weight for Aristotle is absolute, not relative, and the speed of the motion of a natural body stands in direct proportion to the "ampleness" of its nature. The more there is of fire Aristotle claimed, "the faster it performs its proper motion upward..." and "in fact there are many things which move faster downward the more there is of them." [Note 67] This is why Aristotle said that a chunk of earth after being raised to a given height, "will begin to travel the quicker the bigger it is." [Note 68] Consequently, the distances traversed by falling bodies in equal times must be stated to be proportional to their weight (ampleness of their natures, that is). [Note 69] And this law holds true of motion in any direction, provided the motion is natural: "Any chance portion of fire moves upwards and of earth downwards if nothing else gets in the way and a larger portion moves more quickly with the same motion." [Note 70]
The legend spun around the Tower of Pisa was certainly not needed to recognize that such was not the case. The scaffoldings that had to be erected whenever a new temple or monument was constructed in fourth-century Athens must have provided enough cases of falling tools and stones of every size to show that the time of fall from the same height was much the same for the great majority of objects, whatever their size, shape, or weight. Almost a thousand years after Aristotle, yet still living in the same antique world, Philoponus could state without the slightest exaggeration that in Aristotle's law about the fall of bodies there was "something absolutely false." [Note 71] Judging by the sources Philoponus used, it is very likely that this criticism merely echoed those already voiced within the Peripatetic school itself.
One would seek in vain in Aristotle's works traces of even so slight a misgiving about his own conclusions on the laws of physics. This was particularly evident when he discussed the relation of resistance to the moving force. Taken aback by the logical consequences of his premises, Aristotle admitted that a force must be of a certain minimum magnitude to move a given body. It was manifestly impossible to move an oxcart however slowly with one's little finger. But unfortunately even such contradictions could not move him to make even a conditional reappraisal of the validity of his basic assumptions.
The organismic, teleological framework through which he saw nature permitted him no other approach to the phenomena and caused him to take lightly what proved to be all too momentous. As a further consequence, the elements of technical skill, or the more general mechanistic considerations, had to remain severed from the study of nature, and not even a faltering step could be made toward what we call kinematics and dynamics. True, a book called Mechanics in which the problem of the lever and related questions were discussed was compiled in Aristotle's school. But that was in the time of Theophrastus, who found enough reason to oppose his master in not a few points: "With regard to the view that all things are for the sake of an end and nothing is in vain, the assignation of ends is in general not easy, as it is usually stated to be." [Note 72]
In fact, study of the circumstances surrounding the birth and feeding of animals revealed to Theophrastus so many irregularities that he found it impossible to assume in such cases a purposeful action by nature. He could only do what was contrary to the very soul of organismic physics; he called for a program that would "find a certain limit...to the final causation and to the impulse to the better." What he hoped to achieve was a better determination of the "conditions on which real things depend and the relation in which they stand to one another." [Note 73]
In the light of Theophrastus' wholesome advice, it is particularly painful to read certain passages of Aristotle that illustrate in a truly dramatic way how wrong was the direction taken by physical studies when nature was identified as an organism. Aristotle had no choice but to reject the mutual attraction of bodies: "If one removed the earth from the path of one of its particles before it had fallen, it would travel downwards so long as there was nothing to oppose it." [Note 74] He had no patience with "the old saying that like moves to like" and even illustrated his position by a far-reaching hypothetical case: "If the earth were removed to where the moon is now, separate parts of it would not move towards the whole, but towards the place where the whole is now.'' [Note 75] And he could hardly have realized how right he had been when after rejecting the idea of minimum magnitude he added the words that revealed their deepest meaning only after Planck gave his explanation of the black-body radiation: "Suppose for instance someone maintained that there is a minimum magnitude; that man with his minimum would shake the foundations of mathematics." [Note 76] The basic assumptions of Aristotle permitted no distant galaxies or island universes, for the universe as an organism could not exist of apparently independent parts. Similarly the stars and the sun could not be hot, and the Milky Way, the meteors, and comets had to be located below the path of the moon. It was also his infatuation with the concept of organism that led him in a direction diametrically opposed to the concept of inertia. And it is no less ironical that he could assume only as absurd the case of bodies falling with equal (though infinite) speed in a vacuum.
That Aristotle's views on what physics should be could dominate the Hellenistic Age so thoroughly is mainly due to the fact that he was truly Greek in his attitude toward nature. One may admire the intellectual boldness of the Ionian physicists and their bent for mechanistic rationalism; one may even class them as the first representatives of the much admired Hellenic clarity of mind. It nevertheless remains true that the strong reaction that set in with Socrates was no less Greek in character and probably even more so. The post-Aristotelian phase of Greek science was simply unwilling to part with this aspect of the Greek vision of the cosmos. Thus the physics of the Stoics, though putting considerable emphasis on the mechanistic aspects of the vibrations of pneuma, regarded it, however, as the basic, organic stuff of the universe, constituting and pervading everything: ordinary matter, living bodies, and the soul itself. Similarly the great Greek mathematicians and astronomers continued to accept the dictum that physics and astronomy were two separate fields of investigation and that the world, being an organism, was not to be dissected by mathematical analysis. In perfect tune with this did Archimedes restrict himself to statics, turning away from problems that might perhaps have opened to him the realm of infinitesimal calculus. Ptolemy, too, though unable to find use for the concentric spheres of Aristotle, firmly upheld the vitalistic principle when it came to explaining the motion of celestial bodies.
Return to Aristotle - Part 1
Contents
Notes:
- Aristotle, On The Heavens, 297a.
- Aristotle, On The Heavens, 301b.
- Aristotle, On The Heavens, 302b.
- Aristotle, On The Heavens, 303b.
- Aristotle, Meteorologica, 338b.
- F. Solmsen, Aristotle's System of the Physical World. Ithaca, NY: Cornell University Press, 1960, pp. 400-405.
- Aristotle, Meteorologica, 346b.
- Aristotle, Meteorologica, 341b.
- Aristotle, Meteorologica, 344b.
- Aristotle, Meteorologica, 348b.
- Aristotle, Meteorologica, 360a.
- Aristotle, Meteorologica, 367b.
- Aristotle, Meteorologica, 349a.
- Aristotle, Meteorologica, 360a.
- Aristotle, Meteorologica, 361a.
- Aristotle, Meteorologica, 360a.
- Aristotle, Meteorologica, 353a.
- Aristotle, Meteorologica, 355b.
- Aristotle, Meteorologica, 366b.
- Aristotle, Meteorologica, 366b.
- Aristotle, Meteorologica, 368a.
- Aristotle, Meteorologica, 366b.
- Aristotle, Meteorologica, 351a-b.
- Theophrastus, On Fire, pp. 50-73.
- Theophrastus, On Fire, p. 51.
- Aristotle, Meteorologica, 345b.
- Aristotle, Meteorologica, 340b.
- Aristotle, On The Heavens, 249b.
- Aristotle, On The Heavens, 271b.
- Aristotle, On The Heavens, 287b.
- Aristotle. De generatione et corruptione, 316a
- Aristotle, Meteorologica, 344a.
- Aristotle, Meteorologica, 361b.
- Aristotle, Meteorologica, 339a.
- Aristotle, Meteorologica, 366a.
- Aristotle, On The Heavens, 306a.
- Aristotle, On The Heavens, 306a.
- Darwin's comment on reading William Ogle's translation of The Parts of Animals. See Darwin, F., The Life and Letters of Charles Darwin, III. London:1888, p. 252.
- Whittaker, E. T. From Euclid to Eddington: A Study of Conceptions of the External World. Cambridge: Cambridge Universityi Press,1949, p. 46.
- Aristotle, On the Parts of Animals, 641b.
- Aristotle, On The Heavens, 306a.
- Aristotle, On The Heavens, 293b.
- Aristotle,Physics, 248b.
- Aristotle, On The Heavens, 304b.
- Aristotle, On The Heavens, 294a.
- Aristotle, On The Heavens, 301a.
- Aristotle, On The Heavens, 311a.
- Philoponus. "Corollarium de Inani,"in Philoponi in physicorum octo libros commentaria, edited by H. Vitelli. Berlin, 1888, p. 683, 10-17.
- Theophrastus, MetaPhysics, p. 31.
- Theophrastus, MetaPhysics, p. 39.
- Aristotle, On The Heavens, 294a.
- Aristotle, On The Heavens, 310b.
- Aristotle, On The Heavens, 271b.
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