An eternal, unchanging principle that moves all things by being the object they all seek to attain, not through direct action.
Classical Greek philosophers faced a puzzle: if everything that moves must be moved by something else, what explains the source of all motion? Does it regress infinitely, or must there be a starting point? Aristotle’s answer was the “unmoved mover,” developed in the Metaphysics, Book XII (Lambda).
The Argument
Aristotle reasoned that since the cosmos exhibits eternal, regular motion, there must be an ultimate cause of that motion. This cause cannot itself be in motion, otherwise it would require yet another cause to move it, creating an infinite regress. Therefore, a first, unchanging principle must exist that causes all motion without itself being subject to change.
How It Works
The unmoved mover does not push or directly act upon things in the way a hand shoves a block. Instead, it operates as a final cause or end goal. Everything in the universe is drawn toward it the way a person is drawn toward their greatest desire. The unmoved mover is pure actuality (energeia), containing no unrealized potential within itself. It is eternal, immaterial, and absolutely simple, free from the composition of matter and form that marks all changeable things.
Reception and Development
Islamic medieval philosophers, especially Ibn Rushd (Averroes), adopted and reconciled Aristotle’s unmoved mover with monotheistic theology. They argued that God operates as the necessary, eternal first cause and unmoved mover simultaneously satisfying both philosophical reasoning and revealed truth. In Ibn Rushd’s formulation, God’s eternal nature permits no direct action on the material world, instead working through the mediation of celestial intelligences. This preserved Aristotle’s logic while adapting it to Islamic doctrine that reason and revelation, properly understood, cannot contradict each other.