God as the Unmoved Mover
In his Metaphysics, Aristotle reasoned that everything that is in motion owes its movement to something else. He observed the night skies where he witnessed the movement of celestial bodies such as planets and stars. He not only came to believe that the Earth is at the center of all things (a view known as geocentrism) but also wondered what moved them. These celestial objects not only appeared to move but they also never stopped moving. Aristotle, as the empiricist he was, hypothesized that there must be something moving them but which itself did not move. He refers to this as the unmoved mover.
Aristotle further reasoned that it is impossible to have an infinite regress of moved movers, and that there must be a primary mover not moved by anything else. For instance, if A moves then it must be moved by some B, and if B is in motion then it must be moved by some C, and if C is in motion it must be moved by some D, and so on. Aristotle argued that this series cannot go on eternally, and thus must come to a stop in a cause of motion that does not move itself.
Without positing a first unmoved mover one becomes stuck in an infinite regress, where each answer only raises the same question all over again. Aristotle identified the primary, initial mover with God. He claims that God is an autonomous, self-sufficient, and complete being who does not dependent on anything else. The Medieval philosopher and theologian Thomas Aquinas (1225-1274) articulates Aristotle’s notion of the unmoved mover,
“Therefore, whatever is moved is moved by another. If that by which it is moved be itself moved then this also must needs be moved by another, and that by another again. But this cannot go on to infinity, because there would be no first mover, and consequently no other mover… Therefore it is necessary to arrive at a first mover moved by no other, and this everyone understands to be God” (Summa Theologica I, 2, 3).
God as Pure Actuality
Aristotle posited God to have no potentiality, by which he meant that there is no change in God because change implies motion. If God is to be the primary unmoved mover then he must himself be unmoved and thus lack potentiality. This raises the question concerning God, after all, if God is not moving then what is it doing? God cannot be doing anything which would suggest change, so Aristotle supposes that he must be eternally thinking, and only thinks of itself: “The divine mind, then, must think itself, and its thinking is a thinking of thinking” (Metaphysics 1074b).
But if God is only thinking of itself then how can it be the mover of other things like the stars and planets? Aristotle claimed that this was the by the power of attraction akin to a magnet. God is not pushing anything (this would require movement) but things move by the power of God’s being.
However, the God of Aristotle should not be confused with a God who is loving and caring. Aristotle did not believe that God cared nor loved human beings, “It would be ridiculous if one were to charge God with not returning love in the way he is loved, or for a subject to charge a ruler; for to be loved, not to love, characterizes a ruler — or to love in another way” (1)
God Exists Necessarily
God, the unmoved mover, must also exist necessarily. So reasoned Aristotle:
“But since there is something -X- which moves while being itself unmoved, existing actually, X cannot be otherwise in any respect… Thus X is necessarily existent; and qua necessary it is good, and in this sense is a first principle. For ‘the necessary’ has all these meanings [including] ‘that without which excellence is impossible’… Such then is the first principle upon which depend the sensible universe and the world of nature. And its life is like the best that we can temporarily enjoy. But it must be in that state always” (Metaphysics 1072b).
This is to say that God has the property of necessary existence. It is a property that God cannot lack by virtue of what it is.
The philosopher Abraham Edel (1908-2007) concludes that Aristotle’s God is a living and eternal being who is,
“Pure, necessary, fully actual, eternal, unchanging, living, self-conscious thought, embracing within itself the vibrant essence of the world, the ultimate source of physical movement and biological growth, the light that quickens human thought, the good that men unite with momentarily in contemplation, the power that alone can order the whole and given eternal structure to things and processes— such is Aristotle’s God” (2).
1. Aristotle quoted by Edel, A. 1967. Aristotle. p. 103.
2. Edel, A. 1995. Aristotle and His Philosophy. p. 132.