Thinking Things Through
 

First, Aristotle's notion of cause is different from our modern notion of cause.  In general, a cause for Aristotle is something you could use to answer a why question. [Why X? or alternatively, What makes this X?]  In effect, it is an explanation.  But Aristotle thought that there were different ways that one could explain "Why X?", and thus, there are different causes that focus on different aspects of things. 

[Notice that for Aristotle what we explain are substances, generally, not events (as we do with the modern notion of cause).]

The 4 causes are:

 Material:  the matter out of which a thing comes to be
 Formal:  the structure, plan, or essence that makes something what it is
 Efficient:  that which brought about the right changes to make this thin have its particular matter and form
 Final:  the end, purpose, or goal served by a thing having its particular matter and form

Notice that the first two causes are effectively "matter" and "form", which is how Aristotle explained static things, that is things as they are.  Efficient and Final causes were needed to explain change, that is how things came into being. 

Rather than think about Aristotle's categories in terms of the verb "causes", it can be useful to think about it in terms of the verb "makes".

 The material cause is what X is made out of.
 The formal cause is what (structure or underlying properties) makes X an X.
 The efficient cause is what makes (produces) X.
 The final cause is what X is made for.

Here are a couple examples:

1.  What is the cause of the table?
 Material:  The table is made of wood.
 Formal:  Having 4 legs and a flat top makes this a table.
 Efficient:  A carpenter made the table.
 Final:  Having a surface suitable for eating or writing makes this a table.

[Note the use of the verb "make" in each sentence.]

2. What is the cause of an acorn?
Material:  The acorn is made of organic molecules, such as cellulose, and water.
Formal:  This acorn has the structure that is shared by all acorns, resulting 
        from genetic information stored in the oak tree.  That makes it an acorn.
Efficient:  The natural biological processes of the oak tree make the acorn.
Final:  The acorn is made to produce more oak trees.
 

In the case of natural objects, Aristotle thought the purpose or end of the thing (associated with the final cause) was internal to the object.  In effect, there was a plan for the object and its development to follow.  Thus, you can see that the formal cause and the final cause (both dealing with the "plan" of the thing) were closely linked.
 

 Last Updated: 8/28/03