Aristotle – Physics and Metaphysics (Phillip Cary)
Scope: Aristotle, the second most influential philosopher in the West after Plato, was also Plato’s student. He criticized Plato’s theory of forms, because it so completely separated the essence of things and the things of this world. Aristotle modified Plato’s notion of form to create a science of nature or physics. His key idea was to explain the nature of change by reference to four different types of causes: form(“formal cause”), matter (“material cause”), goal(“final cause”), and cause of motion(“efficient cause”).
I.Who was Aristotle?
A.Aristotle was perhaps the greatest mind that ever lived. In addition to being the second most important philosopher of the Western tradition(after Plato), he also invented the sciences of logic, physics, zoology, and botany and coined the term for metaphysics.
B. He was a student in Plato’s Academy, which was the first school called an academy. Evidently, the Academy was a place of open discussion, because the evidence is that Plato had to modify his theory of forms, probably in response to criticism by someone close to him, most likely Aristotle.
C. Aristotle criticized Plato’s theory of the forms.
1.The son of a physician, Aristotle wanted a science of nature, i.e., of the world of things
that grow and change and move.
2.He argued that Plato’s theory of unchanging forms that are separated from the material world would not provide knowledge of how things change.
II.Aristotle invented the term “physics” for his science of nature.
A.It comes from the word physis, Greek for “nature”.
B.A “nature” or physis, means a kind of thing.
C.Because the root verb(phuo) means “to grow”, nature for Aristotle meant a thing that moves, changes, or (especially) grows.
D.Hence, a science of nature is about how things move, grow, and change “according to their own nature”. For example, stones fall, plants grow, animals move around, and human beings reason.
E.Because the Greek term for “science” simply means “knowledge”, the meaning of the phrase “science of physics” for Aristotle’s orginal student would be “knowledge of growing things”.
F.For Aristotle, “movement” was a general term that included growth and any process of change. (Movement in space is “loco-motion”, i.e., local motion, movement with respect to place.)
G.Given this conception of movement, we can say that physics, for Aristotle, was the science of movement, i.e., knowledge of the processes of change in the natural world.
H.”Physics” is thus precisely the kind of knowledge Aristotle wanted but that Plato’s theory of forms couldn’t give him.
III.Aristotle’s thinking addressed the issues of form and matter.
A.Embodied form.
1.Aristotle “corrected” Plato’s theory of forms by insisting that forms in nature are not separate from matter. (Form is, as it were, “embodied” in matter.)
2.Matter means “material”, the stuff out of which a thing is made (as a house is made out of wood, which is its material).
3.Hence, a natural thing, for Aristotle, was a “composite” of form and matter.
4.”House” is what it is (form” and “wood” is what it’s made of (matter).
5.For Aristotle, “form” was the essence or nature of a thing, corresponding to its definition.
B.Art and nature.
1.In Aristotle(and all classical thinkers), art is to nature as artificial is to nature – hence, a carpenter building a house is an “artist”.
2.Thus, “art” (techn in Greek) for Aristotle did not mean only “fine arts” but also the useful arts; carpentry is an art, as is any skill by which humans make something.
3.Artificial things, too, are composites of form and matter (e.g., a house made of wood).
4.Artificial things are distinguished from nature things in that they do not grow according to their own nature but according to the form in the mind of an artist (e.g., the “blueprint” of the house that the carpenter has in mind as he builds it).
C.Form as essence.
1.For Aristotle, a thing is defined by its form, not its matter; the form of a house is “house”, not “wood”.
2.Hence, the essence of a thing is its form.
3.Aristotle would also say that the essence or form is the definition of a thing, the “what it is”.
4.The essence or form of an artificial thing can exist separate from matter, in the mind of the artist.
D.Form as soul.
1.The matter of a living thing is its flesh, whereas the form or essence is its soul.
2.The soul is the nature of a living thing, its principle of life, growth, and movement.
3.In ancient biology, all living things (including plants) had soul, because “soul” was synonymous with life. (A body without soul is a corpse.)
4.For Aristotle, the soul of a living thing was both its principle of life and its principle of movement, because different things have different kinds of souls or natures, depending on the different ways they move and grow.
5.What every human has that plants and animals don’t have is a rational soul, capable of reasoning.
6.Nonrational animals (“brutes” in the ancient terminology) by nature cannot reason but can move around; hence, they have “locomotive” souls, those that are capable of local motion (what we would simply call “movement”).
7.Plants, which are incapable of local motion, have nutritive souls: the kind of “movement” nature to palnts is nutrition and growth.
IV.Aristotle’s physics, or science of moving things, was organized around four different kinds of “causes”, i.e., four different ways of answering the question “why is this so?” Only the first one is what we now would call a “cause”.
A.”Efficient cause”: the cause of being and movement.
1.The artist causes the being (and “growth”) of a house.
2.A living thing is brought into being (and, thus, caused to grow) by its parent through the process of “generation”, or begetting.
3.As the carpenter causes the house to grow according to a form in his or her mind, so does the natural thing grow according to its own form, imparted to it by its parent.
4.Thus, a parent animal imparts to its offspring a soul corresponding to its nature or species (human nature, horse nature, dog nature, and so on).
5.This form, soul, or nature makes the animal what it is (human, horse, dog) and makes it grow into that kind of thing (human, horse, dog).
6.That which gives form to something is its cause of being or cause of movement, called (not by Aristotle but by the later Aristotelian tradition) its “efficient” cause. The word “efficient” has its old meaning of “bringing about an effect”.
7.Hence, “efficient cause” means “cause that has an effect” –the sort of thing we nowadays just call a “cause”. Aristotelian philosophy has three other kinds of cause, or in Aristotle’s terms, “modes of explanation”.
B. “Final cause”: the end or goal of a process.
1.The end of a process of growth is its purpose or goal (telos in Greek).
2.The later Aristotelian tradition called this goal the “final cause”, i.e., the end of a process taken as explaining why it happened this way.
3.In Aristotle’s own terms, the end was “that for the sake of which” a process occurs.
4.Thus, the adult form of an animal is the end of its process of growth, that for the sake of which the child is growing.
C.”Material cause” is the matter “out of which” something is made.
D.”Formal cause” is the form or essence, the “what it is”.
V.For Aristotle, all movement was a process of change from potential to actual (e.g., from child to adult).
A.The actual is the end; the potential is the power of the form at work at the beginning of the process; and movement is how the form gets from one to the other.
B.All natural movement, for Aristotle, is a process by which something becomes what it is (attains its actual form), as a child becomes human by growing to adulthood.
1.Even natural locomotion (sheer physical movement) is a process aimed at an end: each element moves naturally toward its place of rest (stones gravitate downward; fire, upward).
2.In contrast to modern physics, in Aristotelian physics, all natural motion is for an end; it is teleological (from the Greek word telos).
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Aristotle: Physics, Book 2,
Aristotle: Metaphysics, Book 1, Book 12, chapters 6-10.
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上回与阿姗讨论数理科学之类的时候提到亚里斯多德，阿姗问亚里斯
多德不是哲学家吗？我一直未作答，现在抄一份提纲作答。
再说两句：
一）西方的传统，都是青出于蓝而胜于蓝的。比如亚里斯多德，就是
对老柏拉图全面的批判。再说物理学就是对柏拉图的形而上学的批判
。别的数不胜数，如叔本华对康德，贝多芬对海顿与莫扎特。
二）就是讨论的传统。这个在孔子的论语和佛经中也有，但那些弟子
们只是问答而已，没有展开辩论。在柏拉图的对话录里面就不一样了
，苏格拉底是平等对话的一员。记得有一桌关于伦理“公正”的讨论
，当时就有三种观点：Ａ）强者的逻辑，Ｂ）弱者的呼声，Ｃ）共同
的利益。。。
Justice consists of the right ordering of reason, spirit,
and desire, with reason ruling over all. –Socrates
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我也愿咖啡里会有更多平等的讨论，哪怕是强烈的辩论。。。
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