Four Causes - Material Cause

The material cause of an object is equivalent to the nature of the raw material out of which the object is composed. (The word "nature" for Aristotle applies to both its potential in the raw material, and its ultimate finished form. In a sense this form already existed in the material. See Potentiality and actuality.)

Whereas modern physics looks to simple bodies, Aristotle's physics instead treated living things as exemplary. However he also felt that simple natural bodies such as earth, fire, air and water also showed signs of having their own innate sources of motion and change and rest. Fire for example, carries things upwards, unless stopped from doing so. Things like beds and cloaks, formed by human artifice, have no innate tendency to become beds or cloaks for example.

In Aristotelian terminology, material is not the same as substance. Matter has parallels with substance in so far as primary matter serves as the substratum for simple bodies which are not substance: sand and rock (mostly earth), rivers and seas (mostly water), atmosphere and wind (mostly air below and then mostly fire below the moon). Only individuals are said to be substance (subjects) in the primary sense. In a secondary sense, one can also speak of a genus like fig trees. Finally, secondary substance, in a different sense, also applies to man-made artifacts.