Aristotle’s concept of actuality and potentiality is striking for two reasons; its disarming simplicity, and following that its place as a fundamental to understanding many of his other theories. Act and potency follows logically from Aristotle’s thoughts on causation.
Act and potency are dichotomous and parasitic in nature. That is to say, if something possess the potential to be X, its potentiality to be X is reduced as it actually becomes X. In this way pure potentiality is really nothing at all (i.e. the closest thing to nothing) – until it is actualised.
In terms of Aristotle’s causality, matter (or material cause) is potentiality while form (or formal cause) is actuality. When a change occurs to produce X, X’s matter undergoes the change into X and is constant throughout the process. For example, consider bronze: the matter of bronze has the potential to be many things such as a cube or statue. When a bronze cube is changed in a statue, the matter of the bronze remains the same throughout the change.
If a bronze cube’s matter is bronze, then the cubeness is its form. In other words, bronze is always potentially a cube (among other things) and only becomes a cube when it receives the form of cubeness.
Act and potency are related to Aristotle’s empirical epistemology, whereby knowledge is formed through sensation of the forms present in the external world. These forms do not need to be only shapes, they can also be sweetness, blueness, etc. During sensation, the intellect takes on the form of the sensed object without becoming the thing of the sort of form it is sensing.
The God of Aristotle is pure form, or pure actuality. It is perfection in the sense that it has no potentiality, and thus cannot be greater in any way. Logically, there are attributes that follow from being pure actuality: immateriality (as materiality is potentiality), immutability (as change requires potentiality), eternal (as becoming would require change) and etc.
Aristotle’s ideas of act and potency are related to his discussion of goodness, which I will elaborate upon in my next post.