國立清華大學哲學研究所 專任助理教授 陳斐婷 西方思想經典：亞里斯多德《物理學》 國立清華大學哲學研究所 專任助理教授 陳斐婷

Natural Things and Artificial Things “Some existing things are natural, while others are due to other causes. Those that are natural are animals and their parts, plants, and the simple bodies, such as earth, fire, air and water… All these things evidently differ from those that are not naturally constituted, since each of them has within itself a principle of motion and stability [or translated as “a principle of change and rest”] in place, in growth and decay, or in alteration.” (Physics 2.1, 192b8-16) “In contrast to these, a bed, a cloak, or any other <artifact>--insofar as it is described as such, <i.e., as a bed, a cloak, or whatever>, and to the extent that it is a product of a craft—has no innate impulse to change.” (Physics 2.1, 192b16-20)

Natural Things and Artificial Things A natural object (e.g., animals, plants, and the simple bodies such as earth, fire, air and water) has a principle of change and rest within itself. A product of a craft (e.g., a bed, a cloak) has no principle of change and rest within itself. Nature is therefore characterized as the principle of change and rest within the object. Whatever has a nature is a substance. Question: Is nature matter or form? (Is the soul matter of form?)

Four Fashions of Explanation Material explanation: bricks and stones Formal explanation: the form of a house Efficient explanation: the housebuilder Final explanation: shelter and protection

In Its on Right vs. Coincidental Polycleitus made the statue. The baker made the statue. The sculptor made the statue. 你能辨別哪一句是「基於自身緣故」（in its own right）的描述？哪一句是「基於偶然」（coincidental）的描述？

By Purpose vs. By Luck A wants to collect a debt from B; one day A comes to the market-place for some other reason (e.g., wanting to sell his olives) and meets B who happens to be there at the same time. The end—collecting the debt—is not a cause of A’s coming to the market-place. A’s collecting the debt is said to result from luck.

End vs. Consequence In order that; for the sake of that: End (final explanation) So that; consequently; as a result of: Consequence (efficient explanation)

End in Itself vs. Instrumental End In other cases, one thing is a cause of other things by being the end and the good: Two kinds of end/good (1) instrumental end/good（工具性目的/善） (2) end/good in itself（基於自身緣故的目的/善） “Plants grow leaves for the sake of protecting fruit, and send roots down rather than up for the sake of acquiring nourishment …and since everything else is for the end, the form must be what thing are for.” (199a28-32)

Aristotle’s Teleology “We must first say why nature is among the causes that are for something, and then how necessity applies to natural things.” (Physics 2.8, 198b10-16)

Standard Objections to Teleology “Why not suppose that nature acts not for something or because it is better, but of necessity? Zeus’ rain does not fall in order to make the grain grow, but of necessity. For it is necessary that what has been drawn up is cooled, and that what has been cooled and become water comes down, and it is coincidental that this makes the grain grow.” (Physics 2.8, 198b17-21) “Why not suppose, then, that the same is true of the parts of natural organisms? On this view, it is of necessity that, for example, the front teeth grow sharp and well adapted for biting, and the back ones broad and useful for chewing food; this <useful> result was coincidental, not what they were for. The same will be true of all the other parts that seem to be for something.” (Physics 2.8, 198b23-28)

Aristotle’s Reply “This argument, then, and other like it, might puzzle someone. In fact, however, it is impossible for things to be like this. For these <teeth and other parts> and all natural things come to be as they do either always or usually, whereas no result of luck or chance comes to be either always or usually.” (Physics 2.8, 198b33-36) (1) Natural things exhibit great regularity. (2) But chance by definition involves an absence of regularity.

Aristotle’s Reply “If these seem either to be coincidental results or to be for something, and they cannot be coincidental or chance results, they are for something.” (Physics 2.8, 199a4-5) (3) Regularities are either coincidental results or for something. (4) But what happens regularly cannot be a matter of coincidence or chance. (following from 1, 2, 3)

Aristotle’s Argument (1) Natural things exhibit great regularity. (2) But chance by definition involves an absence of regularity. (3) Regularities are either coincidental results or for something. (4) But what happens regularly cannot be a matter of coincidence or chance. (following from (1), (2), (3)) (5) Therefore what happens regularly must be for something.

Further Challenges: Challenge of Agency If we notice that our neighbor always wears a suit and takes the car to work on Mondays and Wednesdays, but wears a sports jacket and cycles on every other day, we suppose there to be some reason for this. ARISTOTLE’S REPLY. Against this Aristotle argues that final explanation does not require deliberation. The absence of deliberation in nature does not prove an absence of final explanation, because (according to Aristotle) after all a craftsman need not deliberate about what the product is produced for.

Challenge of Mechanical Necessity But on other occasions we may speak of mechanical necessity, implying that what always happens in the same way—in accordance with natural laws—is precisely not designed or intended for a purpose. ARISTOTLE’S REPLY. Discovering what the organ or the activity is for is more than discovering mechanical regularity. It involves discovering the connection between this organ or activity and what other parts do, and how they all contribute to the whole life of the animal.

WHAT’S THE END OF A SQUREL? WHAT’S THE END OF AN ACORN?

First Challenge to the Purpose of Life In an animal we select from the regularities that contribute to the preservation of the animal, and say that they are for something, serve a purpose. But many other regularities seem to be simply law-governed chemical or physical processes that may serve no purpose. ARISTOTLE’S REPLY. Two kinds of non-purposive regularities: (1) purposive regularities still require some non-purposive or pre-purposive regularities. (2) some non-purposive regularities may be seen as accidental concomitants or results of purposive regularities.

Challenge Two to the Purpose of Life Granted that we can explain the function of some part or activity by reference to the preservation of the whole animal, does it make sense to speak of the function of the animal as a whole? Does it and its life serve a purpose? ARISTOTLE’S REPLY Step One: By insisting that the individual dog is a member of the species dog Aristotle provides something beyond the individual that the individual life does help to preserve. The point of a dog’s life is to maintain the species, living a canine life and bringing on a new generation. But why are dogs programmed to maintain their species? Step Two: Aristotle sees every kind of thing in the universe as imitating in its own way the changeless activity of god: the stars do so by constant circular motion, animals by maintaining themselves and their species, elements (fire, air, water, earth). Everything that happens in the universe strive toward something unchanging and eternal.

Aristotle’s Challenge to Absolute Necessity “Is what is necessary, necessary on hypothesis, or can it also be unconditionally necessary? People suppose that there is necessity in what comes to be, as a man might think that a city wall had come to be necessarily, because heavy things are by nature such as to sink down, and light things such as to rise to the surface—which is why the stones and foundations go down, the earth goes above them because it is lighter…” Unconditional necessity E.g., From bricks and stones a house necessarily follows. Hypothetical necessity (with telos) E.g., From bricks and stones a house necessarily follows if a house is to be produced. “It is necessary for a thing to be made of iron, if it is to be a saw, and do its work. So it is on some hypothesis that the necessary is necessary… For the necessity is in the matter, the final explanation is in the form.”

Next Week 10/24 斐婷老師出國開會停課乙次 10/31 Aristotle’s Physics Book 4 Chapters 1-5: on Place (I)