The Physics: On Nature
(Book II) On Change and Causation
- Chapter 1: "Nature vs. Art"
- Two kinds of existing things -
- Natural (that which is "by nature") - things which have within themselves a principle of change
Note: According to Aristotle, natural bodies are composed of both compound bodies (e.g., plants and animals) and simple bodies (e.g., the four elements: earth, water, air, and fire).
- Artificial (that which is "by art") - things which require a cause outside themselves to change
Note: We should be careful to note that for Aristotle the "principle of change" INCLUDES the ability to remain at rest.
- "According to Nature" - a phrase used to refer to things as well as their attributes which are an essential part of the thing itself
- Two accounts of "nature" -
- Reductivism - "nature" is determined by the stuff out of which a thing is made
- Water (Thales)
- Air (Anaximenes)
- Apiron (Anaximander)
- Fire (Heraclitus)
- A combination of elements (Empedocles, Anaxagoras)
- Formalism - "nature" is determined by the definition (i.e., form) of a thing
Note: It is important to note that Aristotle distinguishes his account from Platonism by arguing that the form of a thing is not separate from the primary substance as it is in Plato (193b5).
- Chapter 2: "What the 'student of nature' Studies"
The "student of nature" must know both form and substance, but is most interested in the form (though it does not exist apart from substance).
- Chapter 3: "What is Causation?"
- The Four Causes -
- Material Cause - that out of which something is made
- Formal Cause - the form or paradigm from which something is made
- Efficient Cause - the antecedent condition which brings about the event
- Final Cause - that "for the sake of which" something is done
- The Six Modes of Causation -
- Particular or Universal
- Contingent or Necessary (either singular or plural)
- Actual or Potential
- Chapter 4: "Determinism?"
Spontaneity exists in some sense in nature.
Note: Aristotle gives a two-fold reductio to show that spontaneity and chance must be part of the causal structure of the world. First he argues that the account of causation offered by determinists is uncompelling (and undocumented by the "ancients," i.e., the presocratics. Second, he argues that there is no coherent account of chance offered by the ancient nature philosophers. (How this is supposed to be an argument against Determinism is not clear.)
- Chapter 5: "The Nature of Chance"
- Three ways of "coming to be" -
- That which always comes to be in the same way (i.e., necessity)
- That which usually comes to be in the same way
- That which comes to be randomly
- Chance is an internally caused accidental event (197a5)
- Chapter 6: "The Nature of Spontaneity"
Spontaneity is an externally caused accidental event (197b20)
Note: The difference between 'chance' and 'spontaneity' is that while both are accidental (i.e., "unintended"), the former occur in the realm of deliberation while the latter do not. Chance is an event that happens to an intentional agent, while spontaneity occurs only among those incapable of deliberation.
- Chapter 7: "The Subject of Science"
Note: According to Aristotle there are three subjects of investigation:
- The study of what is, but cannot change (i.e., the divine)
- The study of what is, that can change, but not be destroyed (i.e., astronomy)
- The study of what is, that can chance, and that can be destroyed (i.e., everything else) 198a30
- What is a thing? (material cause)
- What caused it to be what it is? (efficient cause)
- Why is it like what it is? (formal cause)
- Why is it better as it is [than other ways it could be]? (final cause)
Chapter 8: "The Teleology of Nature"
- All things come into being in one of three ways:
- Of necessity (they cannot be other than they are)
- Accidentally (either by spontaneity or chance)
- Teleologically (for the sake of something)
- The reductio for natural teleology (198b35ff)
Chapter 9: "Necessity in Nature"
- Two types of Necessity -
- That which is necessary in itself
- That which is necessary "for the sake of" (the "hypothetical)
- The material cause is that which is (hypothetically) necessary
Note: the purpose of a thing is in the form not the matter.
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