Thomistic metaphysics, what is potentiality and actuality specifically?


What exactly is actuality and potentiality?
Some people say that actuality could be almost anything. For example, actuality can reffer to blonde hair, so someone’s hair can go from potentially blonde to actually blonde. Others say that Actuality means to be in accords with your being, so for example, a maan thinking is in a state of actuality, because man is a rational being and man being rational is in accords to his being. So what exactly does it mean? Have I misunderstood it somehow?


Actuality and Potentiality have to do with existence itself. Blond hair is a composite of accident and substance. The accident is the shade of blond and the substance is the hair to which the accident of blondness is applied to. Actuality and Potentiality are spoken of two different ways whether speaking of accident or substance. As an accident, the potentiality is how blond the hair could be, all the different shades. Whereas the actuality is the actual shade of blond the hair possesses and the magnitude to which the substance (hair) participates in the perfection of the accident (pure blond-ness).

As to a substance, the hair itself, actuality and potentiality deal with its existence and how faithfully the individual strands participate in what it means to be hair. Pure actuality, pure existence is only found in God. Thus God grants us existence through creation. The potentiality of our human natures are granted existence through the actuality of God. Think of it this way. Humanity cannot exist by itself. Humanity only exists through the existence of individual men (or women). The actuality lies in the individual existing thing (man) whereas the potentiality lies in the essence (humanity). God, of course, is the exception because his essence and existence are one in the same, thus pure actuality.

Man thinking and acting rationally does not have to do with actuality and potentiality. Yes, the nature of man as a rational and thinking being does concern actuality and potentiality, but the choice of the man to think rationally is simply enacting his will to act in accordance with his nature or not. This affirmation of his nature and work to fulfill the actuality already granted to his existence is instead termed as morality by Aquinas. He makes the distinction between ‘good’ and ‘moral good’. Goodness is the degree in which actuality of a being’s nature participates in the total perfection of that nature. In man, this is how closely our individual created beings reflect Christ. Moral goodness in this sense, is if we choose to act in accordance with that goodness in which we were created. Do we choose to live a life in imitation of Christ rather than just being created like him.

Hope this helps,
Br. Ben, CRM


A simple way to think of it is that a thing is actual insofar as it presently exists. Whereas the potentiality of a thing refers to what could become actual in a thing if it underwent change.


At the most basic level, potentiality and actuality are Aristotle‘s attempts to address the problems presented by Parmenides. Parmenides argued that change was impossible (reality is One). So, any given thing having potentiality within it is just the basic way that Aristotle is trying to account for how things do change. Actuality/potentiality is a metaphysical explanation of change itself.


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