A (rough) restated formulation of Saint Thomas Aquinas’s second way:
- There is at least one item X such that X is caused for its existence
- If (1), then there is at least one cause C of X’s existence
- If (2), then there is a C such that C either is uncaused, is the last member of a finite causal series, or is the last member of an infinite causal series.
- It is impossible that there is a C such that C is the last member of an infinite causal series
- Therefore there is a C such that C is either uncaused or is the last member of a finite causal series
- For every finite causal series, there is some member F which is uncaused
- Therefore there is a C such that C is either uncaused or is the last member of a finite causal series for which there is some F which is uncaused
- Therefore there is either some uncaused C or some uncaused F
- Therefore, whether C or F, there is something uncaused
Et hoc omnes Deum nominant