Or, the perfect actualization, called God.
This medieval Christian term seems to descend from Aristotle's conception of God. For Aristotle, that which exists has properties which can be divided into the actual, which is a realized and existing property of the thing, and the potential, a property of the thing which does not exist now but which may come to be. The potential is converted into the actual by means of an external cause. Aristotle, reasoning backward through the chain of effects and their causes, reaches to the first cause, the first mover, which he calls God. Because this mover is the first, it must be unchanged, unmoved, unaffected, by other causes. It has no potentiality - it is pure actuality.
There is an opposite quantity, called prima materia by the alchemists: the formless base of matter, all potential, no actualization.
Aristotle makes no claims, as far as I can tell, for the actual existence of prima materia, the way he does for actus purus. All things in the world, says Aristotle, are a little of both; and God is only one.
He has more to say about it, but let's not get into that. Instead, let's look at an image we've looked at a million times before, and see if we can't see something new in it:
First, let's think about it in terms of a literal application of this actus purus/prima materia dichotomy. Naturally, in a work of art you can't have a literal interpretation of very abstract philosophical ideas. But in this image, Michelangelo gives us a God in a state of very high motion - the cloth on his robes shows him moving, and he is surrounded by fluttering forms, a frenzy of motion. He stretches forward, he reaches toward Adam. His potential for motion is actualized, and his potential for action is actualized. He is an actus purus.
Adam, on the other hand, is barely risen above prima materia. His muscles do not tense in order to act - he takes no action. God's finger reaches actively, Adam's finger droops passively. Adam's forehead is smooth, God's is furrowed. God acts out of a block of complex forms, swooping cloth and angels; Adam sits on a vague landscape, formless colors suggesting the Earth.
This is one reading of this scene. Let's take another reading. God acts; Adam does not act. Who is the more powerful, in the psychological dynamics of this interaction? Adam lets God come to him; Adam, in his passivity, drives an active God into a maelstrom of passions. It is Adam who is the superior, and moreover, he is superior in the form we traditionally ascribe to the feminine: by merely showing himself, being himself, languidly, he inspires action in the masculine party.
But perhaps it is not fair to Michelangelo to describe him from a modern perspective like this. Let's rephrase the same thing in terms of the Aristotelian concepts. Who is the unmoved mover here? Again, it is Adam. In the narrative, God's touch will cause Adam to gain motion. But in the picture actually at hand, Adam does nothing for God, and God does everything for Adam. Adam causes God to move; God does not cause Adam to move. This is a scene of first things, and in any scene of first things, we find a first cause. Adam is the first cause; God's motions are that which is caused.
So - interesting, a little: a sphinx of an image, shimmering between one interpretation and another inside of a single set of concepts. Who is the first mover here? It depends on what you're looking for.
But one ought not to read too much into it. Michelangelo surely knew something of the Aristotelian concepts and their scholastic Christian interpretation. But he was an artist. He almost certaintly did not intellectually derive this image from a logical process; he probably had this image simply pop into his head, an intuitive outcome of everything he knew, and of his inspiration.
Why think about it in these terms at all then? Because it is very difficult to look at something familiar with new eyes. The Mona Lisa, the Sistine Ceiling - we are in danger of losing them, because of their familiarity. If we experiment with analyzing them from an alien perspective, legitimate or not, we can scrape the scales from our eyes and see them again in their dazzling originality. We can restore to them the shock of the new.
Hei Oulu! On kiva nähdä taas. Toivottavasti kaikki on hyvin sinulle!