In his study on metaphysics Aristotle introduces a distinction between matter and form. This distinction is enacted in the definition of matter as potentiality or dunamis and form as actuality or energaia. Aristotle states that actuality is to potentiality as ‘someone awake is to someone asleep’ or as ‘that which has been shaped out of some matter to the matter from which it is shaped’. Something is always potentially the thing that comes after it. However, ‘if there is a first thing which is no longer called after something else, and said to be of it, this is prime matter’. For Aristotle, actuality is really real and potentiality is only half real. Aristotle also stated that actuality has a priority over potentiality because it is capable of being. His argument for this priority has two subarguments. First, is that logically the actual is not defined by the potential but the potential by the actual. For example, ‘visible’ means capable of being seen. His second temporal reason is that only an actual substance can actually physically produce something. The potential does not have the power to produce anything. For example the seed, or potential substance, must have been preceded by an adult or actual substance. For Aristotle, the potential is created by the actual therefore actuality precedes potentiality.
 Aristotle. “Metaphysics: Book Theta (IX) (extract)” in The Complete Works of Aristotle: The Revised Oxford Translation , Barnes, Jonathan; Aristotle , 1984, p.1657
 Deranty Dr. J, Lecture 9, Aristotle, in “Mind, Meaning and Metaphysics”, PHI130, Macquarie University 2011ysic
 Aristotle, Metaphysics, p.1657
 Deranty Dr. J. Lecture 9
 Deranty, Dr. J., Lecture 9
 Aristotle, Metaphysics, p.1655