A central question in all of ancient thought was
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A central question in all of ancient thought was

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Introduction:

PAPER 1: ARISTOTLE ON THE MOTION OF THE HEAVENS THE CASE A central question in all of ancient thought was, "Why do things change?" It made sense why they would stay the same, but the first questions about the natural world had to do with things that changed. Among the changes that were most obvious to the ancients were the positions of objects in the sky. The sun, moon, and all the constellations of stars rise in the east and set in the west every day. While the exact point on the horizon where the sun rises, how long it is in the sky, and the path it takes are not the same day to day, they are periodic, repeating over and over again each year. The fixed stars, those in the constellations, also rise and set, and are always in the same relative places. The constellations themselves remain stable, as do the distances in the sky between them. However, like the sun, their motion varies daily in a regular fashion. This motion, however, appears to be quicker than that of the sun so that the stars that appear on the horizon at midnight the night before will be a bit higher in the sky the next night, and higher the night after that, and so on, returning to the horizon at midnight 365 days later. Charted out, these stars rotate around the North Star. These are well-established facts, and were for the ancients as well, but what accounts for the change and its periodic regularity? THE SCIENTIST Aristotle (384-322 Bc) was the son of Nicomachus, the physician of King Amyntas of Macedonia. He studied with Plato at his school,the Academy, for twenty years, until Plato's death. He was invited to return to Macedonia by Philip in order to become the personal tutor of his son Alexander, who would later conquer much of the known world. Upon Philip's death, Aristotle returned to Athens and opened his own school, called the Lyceum. Upon the death of Alexander, Aristotle was chased from Athens to Chalcis, where he died soon after. His treatises on astronomy, physics, chemistry, biology, meteorology, and many other subjects are among the first systematic works on the natural world based on observation. 

Topic:

Ancient astronomers had to explain the periodicity of the motions of heavenly bodies. Your job is to read the excerpt of Aristotle's astronomical work (beginning on p. 327) and explain his answer. Explain the deductivist approach to science. How would a deductivist understand Aristotle's work setting out a picture of the heavens? Discuss in detail how Aristotle argues from metaphysical principles that the motion of the heavens must be eternal, circular, and regular. What are the metaphysical first principles he used and what are his deductive arguments from them to his resulting claims about heavenly motion? Does Aristotle's work remain truly within the deductivist method or is there another sort of reasoning also in play?

Reading material:

Reading is Aristotle-On the Heavens From Aristotle, "De Caelo," On the Heavens, in The Oxford Translation ofAristotle, vol. 2, ed. W. D. Ross, trans. J. L. Stocks (Oxford: Oxford University Press, 1930), 283, 286, 288-89. Reprinted by permission of Oxford University Press.

 BOOK 11 

CHAPTER I 

That the heavens as a whole neither came into being nor admits of destruction, as some assert, but is one and eternal, with no end or beginning of its total duration, containing and embracing in itself the infinity of time, we may convince ourselves not only by the arguments already set forth but also by a consideration of the views of those who differ from us in providing for its generation. If our view is a possible one, and the manner of generation which they assert is impossible, this fact will have great weight in convincing us of the immortality and eternity of the world. Hence it is well to persuade oneself of the truth of the ancient and truly traditional theories, that there is some immortal and divine thing which possesses movement, but movement such as has no limit and is rather itself the limit of all other movement. 

CHAPTER III ...

 Everything which has a function exists for its function. The activity of God is immortality, i.e. eternal life. Therefore the movement of that which is divine must be eternal. But such is the heaven, viz. a divine body, and for that reason to it is given the circular body whose nature it is to move always in a circle. Why, then, is not the whole body of the heaven of the same character as that part? Because there must be something at rest at the centre of the revolving body; and of that body no part can be at rest, either elsewhere or at the centre. It could do so only if the body's natural movement were towards the centre. But the circular movement is natural, since otherwise it could not be eternal: for nothing unnatural is eternal. The unnatural is subsequent to the natural, being a derangement of the natural which occurs in the course of its generation. Earth then has to exist; for it is earth which is at rest at the centre. (At present we may take this for granted: it shall be explained later.) But if earth must exist, so must fire. For, if one of a pair of contraries naturally exists, the other, if it is really contrary, exists also naturally. In some form it must be present, since the matter of contraries is the same. Also, the positive is prior to its privation (warm, for instance, to cold), and rest and heaviness stand for the privation of lightness and movement. But further, if fire and earth exist, the intermediate bodies must exist also: each element stands in a contrary relation to every other. (This, again, we will here take for granted and try later to explain.) these four elements generation clearly is involved, since none of them can be eternal: for contraries interact with one another and destroy one another. Further, it is inconceivable that a movable body should be eternal, if its movement cannot be regarded as naturally eternal: and these bodies we know to possess movement. Thus we see that generation is necessarily involved. But if so, there must be at least one other circular motion: for a single movement ofthe whole heaven would necessitate an identical relation ofthe elements of bodies to one another. This matter also shall be cleared up in what follows: but for the present so much is clear, that the reason why there is more than one circular body is the necessity of generation, which follows on the presence of fire, which, with that of the other bodies, follows on that of earth; and earth is required because eternal movement in one body necessitates eternal rest in another. 

CHAPTER VI 

We have next to show that the movement of the heaven is regular and not irregular. This applies only to the first heaven and the first movement; for the lower spheres exhibit a composition of several movements into one. If the movement is uneven, clearly there will be acceleration, maximum speed, and retardation, since these appear in all irregular motions. The maximum may occur either at the starting-point or at the goal or between the two; and we expect natural motion to reach its maximum at the goal, unnatural motion at the starting-point, and missiles midway between the two. But circular movement, having no beginning or limit or middle in the direct sense of the words, has neither whence nor whither nor middle: for in time it is eternal, and in length it returns upon itselfwithout a break. Ifthen its movement has no maximum, it can have no irregularity, since irregularity is produced by retardation and acceleration. Further, since everything that is moved is moved by something, the cause of the irregularity of movement must lie either in the mover or in the moved or both. For if the mover moved not always with the same force, or if the moved were altered and did not remain the same, or if both were to change, the result might well be an irregular movement in the moved. But none of these possibilities can be conceived as actual in the case of the heavens. As to that which is moved, we have shown that it is primary and simple and ungenerated and indestructible and generally unchanging; and the mover has an even better right to these attributes. It is the primary that moves the primary, the simple the simple, the indestructible and ungenerated that which is indestructible and ungenerated. Since then that which is moved, being a body, is nevertheless unchanging, how should the mover, which is incorporeal, be changed? It follows then, further, that the motion cannot be irregular. For if irregularity occurs, there must be change either in the movement as a whole, from fast to slow and slow to fast, or in its parts. That there is no irregularity in the parts is obvious, since, if there were, some divergence of the stars would have taken place before now in the infinity of time, as one moved slower and another faster: but no alteration of their intervals is ever observed. Nor again is a change in the movement as a whole admissible. Retardation is always due to incapacity, and incapacity is unnatural. The incapacities of animals, age, decay, and the like, are all unnatural, due, it seems, to the fact that the whole animal complex is made up of materials which differ in respect of their proper places, and no single part occupies its own place. If therefore that which is primary contains nothing unnatural, being simple and unmixed and in its proper place and having no contrary, then it has no place for incapacity, nor, consequently, for retardation or (since acceleration involves retardation) for acceleration. Again, it is inconceivable that the mover should first show incapacity for an infinite time, and capacity afterwards for another infinity. For clearly nothing which, like incapacity, unnatural ever continues for an infinity of time; nor does the unnatural endure as long as the natural, or any form of incapacity as long as the capacity. But if the movement is retarded it must necessarily be retarded for an infinite time. Equally impossible is perpetual acceleration or perpetual retardation. For such movement would be infinite and indefinite, but every movement, in our view, proceeds from one point to another and is definite in character. Again, suppose one assumes a minimum time in less than which the heaven could not complete its movement. For, as a given walk or a given exercise on the harp cannot take any and every time, but every performance has its definite minimum time which is unsurpassable, so, one might suppose, the movement of the heaven could not be completed in any and every time. But in that case perpetual acceleration is impossible (and, equally, perpetual retardation: for the argument holds of both and each), if we may take acceleration to proceed by identical or increasing additions of speed and for an infinite time. The remaining alternative is to say that the movement exhibits an alternation of slower and faster: but this is a mere fiction and quite inconceivable. Further, irregularity of this kind would be particularly unlikely to pass unobserved, since contrast makes observation easy. That there is one heaven, then, only, and that it is ungenerated and eternal, and further that its movement is regular, has now been sufficiently explained.

Hint
ManagementThe solution to the challenge of heavenly bodies’ motion has been attained through combined activity of multiple observers, astronomers, mathematicians, and computers. This has prevailed form civilization’s dawn up to the 20th Century. Early races such as the Egyptians and Indians have recorded observations. ...

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