Aristotle posited four distinct types of causes that produce changes in things. These causes are 1) the formal cause, which determines what a thing is; 2) the material cause, that out of which a thing is made; 3) the efficient cause, that by which a thing is made; and 4) the final cause, that for which a thing is made, or its purpose. Table 3.1 The Four Causes Defined Illustrated Formal cause That which determines what a thing is The sculptor’s idea or plan for a sculpture Material