Aristotle on Change

1. It is characteristic of substances (according to the Categories) to undergo change. And "natural things are some or all of them subject to change" (Phys. I. 2, 185a12-13).
   
2. We know this was a topic that puzzled Aristotle's predecessors. Parmenides denied it altogether; Plato said that real things don't change.
   
3. Aristotle gives an example of an argument against change that sounds typically Parmenidean (191a28-29):

   What is cannot come to be (since it already is), while nothing can come to be from what is not.

   The argument is basically that there are only two ways that something can come to be: either from what is, or from what is not. But neither is possible. Therefore, nothing can come to be.
   

4. Aristotle gives an analysis of change that enables him to avoid this dilemma. His account is designed to explain both how change in general is possible, and how coming into existence is possible.
   
5. Aristotle's account is contained in Phys. I, 7. He insists that there must be three basic ingredients in every case of change. (Plato's treatment only mentions two: a pair of opposites). In addition to a pair of opposites, there must be an underlying subject of change.
   
   The basic case of change involves a pair of opposed or contrary properties and a subject that loses one of them and gains the other. But Aristotle does not even insist that there be an opposed pair of properties (191a6-7):

   In another way, however, there need not be two [contraries]; for just one of the contraries is enough, by its absence or presence, to produce the thing.

   So the ingredients Aristotle insists on are: an underlying subject, a form (i.e., a positive property) and a lack (or privation) of that form.
   

6. Examples:
   
   1. A man who was unmusical becomes musical.
   2. Some bronze (which was shapeless) becomes a statue.
      
7. The subject - the man, or the bronze - persists through the change. Of the other terms involved, some (unmusical, shapelessness) cease to exist, while some (musical, the statue) come into existence.
   
8. Change is thus not, strictly speaking, coming to be from what is, since a musical man does not become a musical man. (Cf. the Parmenidean argument above.)
   
   Nor is it, strictly speaking, coming to be from what is not, since we don't have a musical man coming to be from nothing.
   
   Yet in a way it is coming to be from what is not, since the musical man comes to be from a lack (unmusical), which is something that is not (191b15).
   
   And in a way it is coming to be from what is, since the musical man comes to be from something which is a man (a man who was, of course, unmusical).
   
9. Aristotle notes (190b11) an important feature of change: that which comes to be is always composite.
   
   For example, what comes to be is the musical man. But what about Aristotle's other case? What is the statue a compound of? Aristotle's answer: matter and form.
   
10. We thus see two different kinds of change in Aristotle's account:
    
    1. Accidental change (e.g., alteration of a substance): the subject is a substance. E.g., the man becomes a musician, Socrates becomes pale.
       
    2. Substantial change (generation and destruction of a substance): the subject is matter, the form is the form of a substance. E.g., the bronze becomes a statue, a seed becomes a tiger, an acorn becomes an oak tree.

    Accidental change can be accommodated within the world of the Categories, a world in which primary substances (individual horses, trees, etc.) are the basic individuals. But what of substantial change? This seems to threaten the ontology of the Categories. For substantial change requires a subject (viz., matter) that seems more basic than the individual plants and animals of the Categories.
    

11. Problem: if the primary substances of the Categories turn out to be compounds of form and matter, how can they be the basic ingredients of the world?
    
    Example: a builder is not a basic individual, for Aristotle. A builder is a compound of a subject and a property: a substance (a human being) and a characteristic (s)he happens to have - the knowledge of building. So why then isn't a tiger not a basic individual, since it, too, is a compound of a subject and a property: matter and a form that supervenes, a form the matter happens to have?

Go to next lecture on The Four Causes.

Go to previous lecture on  Predication and Ontology: Categories

  Return to the PHIL 320 Home Page

• This page was last updated on 11/12/00.