Natural theology and natural law › What the Five Ways aim to establish

Each Way begins from some feature Aquinas finds in the world and reasons toward a first principle. They are offered as demonstrations, rather than as five measurements whose results can be averaged. Assessing them requires examining their premises about change, causation, necessity, degrees of perfection, and natural ends.

Aquinas names the conclusion of each argument God. The compressed arguments do not, by themselves, establish every attribute discussed later in the Summa. The subsequent questions investigate such matters as simplicity and goodness. Treating the Five Ways as the complete argument for every Christian doctrine would erase that further work.

The opposite simplification is also misleading. Aquinas does not think reason can say nothing about God beyond an unidentified first cause. His project includes further reasoning about divine attributes, while recognizing limits to natural knowledge. The distinction concerns what particular arguments establish and how later claims are supported.