The First Cause and the Unmoved Mover

Aristotle Develops the Cosmological Argument

Aristotle observed that the world around him was in a state of constant flux – that everything was in motion all the time. He developed what has come to be known as the Cosmological Argument in Book 8 of Physics although elements that contribute to its understanding can be found throughout his writings especially Book 12 of Metaphysics.

In Parts 4-6 of Book 8 of Physics, Aristotle finds “surprising difficulties” in explaining even commonplace change. He therefore concluded “…the bare existence of change requires the postulation of a First Cause, an Unmoved Mover whose necessecessary existence underpins the ceaseless activity of the world…”

Aristotle further claims the concepts - insofar as they are correct - of ‘before’ and ‘after’ require a first principle. Drawing explicitly on Parmenides’ conclusion that “nothing comes from nothing”, Aristotle deduced that the postulation of a God or being with the essential attributes of the God of Islam, Christianity, and Judiasim, (eternal, unchangeable, immovable, perfectly wise, etc.) was logically necessary otherwise the cosmos would lacke an antecedent state.