The Body Problem in Aristotle

Aristode, then, is committed to theses (l)-(3). In this chapter, however, I show that, far from revealing a deep contradiction in Aristotle s thought, the body problem admits of a resolution that throws considerable light on several aspects of his metaphysical system. The resolution begins with a thesis concerning Aristotle s philosophy of mathematics and its relation to the conception of science Aristode articulates in the Posterior Analytics. In order to resolve completely the body problem, though, such a thesis must be combined with theses about the relationship between substance, form, motion and quantity. 

The solution to the body problem is in some ways already at hand. Two different conceptions of body have been located—I will call them body-s and body-q for body in the category of substance and body in the category of quantity respectively. Body-s is mobile limited neyeQoq in three dimensions, while body-q is limited pdyeSoq in three dimensions. The body problem arises because Aristotle accepts that body is in both the category of substance and quantity But now, the claim that body is in the category of substance can be understood as the claim that body-s is in the category of substance, while the daim... 

Thesis I finds support in Aristotle s division of substance in book XU of die Metaphysics. Thesis II comes direedy from Aristode s discussion of the category of quantity in the Metaphysics. Thesis III comes direedy from Aristode s discussion of change in the Physics. Thesis IV comes from Aristode s claim that form is a principle of motion. Thesis V comes from Aristode s views that composite substances have forms and that bodies in the category of substance are composites. Thesis VI is, of all the theses, the most controversial In fact, I shall reject it in chapter 4. Nonetheless, as shall become apparent there, the connection between prime matter and extension is sufficiendy intimate that the above solution to the body problem can easily be altered in order to accommodate what is the correct understanding of prime matter. Finally, thesis VII emerges from an examination of Aristode s understanding of the qua locution. 

Clarke s reference to eye-beams relies on an understanding of an active eye that emits pneuma to unite with particles projected by the object. This way of seeing also resembles the neo-platonic theory of love - a concept that popular texts, such as The Problems of Aristotle, rendered in elementary form the louer sendeth co[nt]inuall beames of the eie towards that which he loueth. And those beames are like vnto arrowes, because the louer doth dart them into the bodie (sig. Lyv). The evil eye depends on the same principles -vapours are emitted from one person s eye to penetrate the victim s eyes. 

Ihe problem arises as a result of Aristotle s treatment of body in the Categories. Aristotle, it would seem, commits himself to the following three inconsistent theses. 

Before going on I would like to comment on this case briefly. First of all, I told the story in a weird way. The natural version of the story would go like this. Even before the sophisticated scientific accounts were developed, people knew some basic facts about the motion of bodies in particular, they knew that unsupported bodies fall down. These facts were not described in terms peculiar to any scientific theory. Aristotle gave a new, scientific account of these facts. Then Newton came along and gave a different scientific account. Both of them offered theoretical redescriptions of the old facts. It is because of these old facts that it is natural to judge the two scientific accounts were dealing with the same domain. Indeed, in the presence of the old facts, the intersection of the two theories is so obvious that one needs highly sophisticated philosophical views in order to raise doubts about it. I have no problem with the natural version. It is the historically correct account of what happened. 

They translated Aristotle and studied his works they cultivated astronomy, optics and the various branches of medicine and they enriched these sciences with new truths. We owe to them the spread of the use of algebra, which had been applied by the Greeks only to one class of problem. If it is true that their fanatical interest in the secrets of alchemy and the elixir of life sullied their work in chemistry, it must be remembered that it was they who revived, or rather invented, this science which had till then been confused with pharmacy or with technical skill in the arts. It was with them that chemistry appeared for the first time as the analysis of bodies into discernible elements and as the theory of their compounds and the laws of such compounds. 

Greek philosophers viewed the physical world as matter organized in the form of bodies having length, breadth, and depth that could act and be acted upon. They also believed that these bodies made up a material continuum unpunctuated by voids. Within such a universe, they speculated about the creation and destruction of bodies, their causes, the essence they consisted of, and the purpose they existed for. Surfaces did not fit easily into these ancient pictures of the world, even those painted by the atomists, who admitted to the existence of voids. The problem of defining the boundary or limit of a body or between two adjacent bodies led Aristotle (fourth century BC) and others to deny that a surface has any substance. Given Aristotle s dominance in ancient philosophy, his view of surfaces persisted for many centuries, and may have delayed serious theoretical speculation about the nature of solid surfaces [2]. 

The problem that Duhem sees with atomism is, therefore, not so much its status as a metaphysical hypothesis, but its weak explanatory power. An examination of atomic notation provides Duhem with the means to clearly pose the problem of the relationship between the sensible properties of a compoimd and the nature of its constituent elements. This critical analysis targets not only atoms but also elements in the sense of simple bodies that explain the nature of the compound. The typical reasoning of a post-Lavoisian chemist is to explain the sensible properties of a compoimd by reference to the nature and proportion of its constituent elements. Duhem takes the opposite tack and suggests that the compound should be used to explain the properties of the element. Valencies should not be considered as the invariable intrinsic properties of each atom (thus, Duhem refused to use the contemporary term atomicity ) but rather as properties of a particular compound. Using what he had learned from Aristotle s philosophy, Duhem rejects the choice between atom and element, thereby escaping the stifling to-and-fro between simple and composed. The mixt — the phenomenal compound body that the chemist has to deal with — cannot be reduced to elements or to atoms. It is this concept of irreducibility placed at the heart of chemical theory that justifies Duhem s use of the outmoded term mixt in the presentation of his philosophy of chemistry. 

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