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WillowOne's Positions

Prime Mover Argument

Form

  1. Some things are in motion (that is, changing: moving from potentiality to actuality).
  2. Whatever is in motion is put in motion by something else.
  3. There cannot be an infinite regress of movers.
  4. Therefore there must be a first mover, itself unmoved.
  5. (Usually added) This unmoved mover is God.

This is the first of Thomas Aquinas's Five Ways (Summa Theologica, I, q.2, a.3), derived from Aristotle's Physics (Book VIII) and Metaphysics (Book XII). It is a close relative of the First Cause Argument, framed in terms of change rather than causation.

My Positions

  1. My objections to the First Cause Argument apply here in full: the premises are contradicted by the conclusion, infinite regress is not shown to be impossible, and nothing about an unmoved mover implies a personal god.
  2. The argument depends on Aristotelian physics, in which rest is the natural state and motion requires continuous explanation. Since Newton's first law, we know that uniform motion requires no mover at all. Only changes in motion require a force, and the forces are themselves physical.
  3. Aristotle's own unmoved mover was not a creator, did not know the world existed, and did not intervene in it. It moved things only by being an object of desire. The apologist who borrows the argument quietly swaps in a very different god at the end.
  4. An "unmoved mover" that is changeless cannot act, since acting is a change. See Kalam Cosmological Argument and God on the incoherence of a timeless, changeless agent.

Also see