Aristotle's Physics, Book II

Philosophy 3383, Spring 1996

Dr. Cynthia Freeland

402 AH, 743-2993,

All readings are in Ancient Greek Philosophy, ed. Cohen, Curd, and Reeve

Aristotle's Theory of Causes and Natural Teleology

Physics: Highlights Book II

Chapter 1.

  • 1. Some things are natural, others due to other causes.

    Natural: animals, their parts, plants, the elements

    Other: bed, cloak, other artifacts made by a craft

    Natural = what has within itself a principle of motion and stability, growth and decay, or alteration.

  • 2. What is nature? (or: what is the nature in a thing?)

    Some say matter: the primary constituent. Example: the wood in a bed. (If you plant a bed, it might grow into a tree, not into another bed.)

    Others say form: The wood isn't the nature of the bed, only potentially so. The same holds for the matter of flesh or bone. The shape or form is nature, it belongs to a thing and is not separable, except in an account.

    Aristotle: Form is more truly nature than matter. What is it that grows? Not what it's growing from, but what it's growing into.

    Chapter 2. The student of nature (="the physicist")

    Mathematician: studies surfaces, solids, lengths, points, features separable from bodies in thought.

    Student of nature: studies bodies which have these features as coincidents. Platonists: study forms, which is like the study of mathematics.

    Aristotle: We should study nature as a form in a matter (like snubness, which is a certain shape in a certain matter, i.e. a rounded nose).

    Chapter 3. Types of causes (the four causes)

    1. material constituent: the bronze in a statue, the silver in a bowl

    2. formal pattern, account of the essence (octave=ration of 2/1)

    3. efficient source of change: the father causes the child

    4. final the end, what it is for; health causes walking

    All these can be described or modified in various ways: general/specific; coincidental; actual/potential (see summary at 195b12-16).

    Chapter 4. Luck and Chance: introduction

    A review of the opnions (endoxa).

    Some say that everything has a definite cause and there is no luck.

    Earlier philosophers didn't mention chance, but should have.

    Others say that chance causes everything; this is "amazing."

    Chapter 5. Luck defined

    Luck and chance are both things that occur "for something" or with some sort of an end, but that do so coincidentally. Luck occurs specifically among things in accord with decision (or things with thought). (Luck is chance that occurs to people.)

    Example: A man went to the market to sell olives, and by luck, met someone who owed him money, who repaid the debt. He was lucky.

    Chapter 6. Chance defined

    Chance is broader than luck; it can involve animals, children, or inanimate objects.

    It is the sort of thing that nature could have caused for a purpose, but that has a coincidental cause.

    Example: A statue of so-and-so fell onto the man who had murdered so-and-so. By chance that the murderer met his proper justice.

    Chapter 7. Summary thus far

    The student of nature must study all the causes. But some things are super-natural (beyond nature): things that initiate motion without being in motion. (Preview of Aristotle's Prime Mover or God.) To some extent, form is like this, or the final cause.

    Chapter 8. The relation between final causation and necessity

    Why should nature act for purposes, and not simply due to (material) necessity?

    Example: The rain comes in order to make the grain grow. But why could this not just occur due to necessary facts about clouds, sun, etc.? And similarly, why could it not be that teeth just grow as they do owing to various material causes?

    Aristotle's response: This is impossible. These processes are for something and they occur quite regularly. But purposive things which occur only by chance are the exception, not the rule. There must be something that explains why these purposive things come about so regularly -- this must be because they come about for a reason or for a purpose.

    Chapter 9. Is necessity in nature conditional or unqualified? (Is it hypothetical or is it absolute?)

    What is the role of the necessity of material in things' natures?

    Example of "absolute" necessity: A wall would come about because of facts about its materials--the stones go to the bottom, the wood to the top because it's lighter.

    Refutation: No: a wall comes about to provide protection.

    Things that come to be for something have a necessary nature, but do not come about because of this (material) necessity.

    Hypothetical necessity in nature: A form is hypothesized, and so a matter is necessitated. If there is to be a saw, there must be iron. The necessity belongs mainly to the material cause (necessarily iron teeth will cut something softer like wood). But it is also in a way in the form: the form of sawing implies cutting, cutting implies teeth, and teeth imply something hard like iron.

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    March 14, 1996