Four causes

Aristotle held that there were four kinds of causes:

• A thing's material cause is the material of which it consists. (For a table, that might be wood; for a statue, that might be bronze or marble.)
• A thing's formal cause is its form, i.e. the arrangement of that matter.
• A thing's efficient or moving cause is "the primary source of the change or rest." An efficient cause of x can be present even if x is never actually produced and so should not be confused with a sufficient cause. (Aristotle argues that, for a table, this would be the art of table-making, which is the principle guiding its creation.)
• A thing's final cause is its aim or purpose. That for which the sake of which a thing is what it is. (For a seed, it might be an adult plant. For a sailboat, it might be sailing. For a ball at the top of a ramp, it might be coming to rest at the bottom.)