more from Thomas Aquinas

Single Idea 21269

[catalogued under 28. God / B. Proving God / 3. Proofs of Evidence / a. Cosmological Proof]

Full Idea

A thing can only be reduced from potentiality to actuality by something actual. A thing can never be in actuality and potentiality in the same respect. So what is moved must be moved by another. But this cannot go on to infinity, with no first mover.

Gist of Idea

Way 1: the infinite chain of potential-to-actual movement has to have a first mover


Thomas Aquinas (Summa Theologicae [1265], Ia,Q02,Art3,Reply)

Book Reference

'The Existence of God', ed/tr. Hick,John [Macmillan 1964], p.83

A Reaction

[compressed] This relies on the Aristotelian ideas of potentiality and actuality. We might talk about things moving, but lacking the 'power' to move. This is almost identical to Plato in 'The Laws' (which I guess Aquinas knew nothing of).