The Teleological Argument - Aquinas' Fifth Way
Religious Studies: OCR A Level, topic 1.4.1
A Posteriori Arguments: The Teleological Argument
The word teleological comes from the Greek word telos, meaning goal or purpose. The world and things in it seem to move towards certain goals or ends.
A posteriori arguments
- Arguments based on observation are called in Latin a posteriori arguments.
- These have a prominent place in the philosophy of religion.
- Aquinas’ five ways are all a posteriori as he did not believe an a priori argument (an argument based purely on logic or deduction) for God would be valid.
- This was a consequence of the epistemology (theory of knowledge) that he had inherited from Aristotle.
Efficient & final causes
- Aristotelian-Thomistic scholars (working in the tradition of Aristotle and St. Thomas Aquinas) say that efficient causality is unthinkable without final causality.
- Efficient causes change things or bring them into existence (e.g. heat is the efficient cause of the melting of ice and phosphorous in a match head is the efficient cause of the flame on a match).
- Final causes are just the outcome of these causes – the water/the flame. When we talk about telos, we mean these final causes.
The Teleological Argument: Aquinas' Fifth Way
Teleological arguments go all the way back to Plato. Plato proposed that the cosmos is directed by intelligence.
Aquinas' fifth way
- Aquinas' fifth way uses the observation that non-intelligent organic life acts in certain ordered, cyclical and purposive ways. For example:
- Given the right conditions, acorns always grow into oak trees and not wombats.
- The moon has a regular 29 and a half-day cycle.
Acting for goals & intelligence
- The fact that non-intelligent things (like acorns and plankton) always act in certain ways for certain goals implies that they were given those goals by intelligence because only intelligent beings can assign a purpose to things and move that thing towards its purpose.
Archery example
- Aquinas gives the example of arrows fired by an archer to hit a target.
- Without the archer giving the purposive direction, the arrow would remain in the quiver.
- A simplified version of the argument might say that the order and purpose we see in the universe needs an explanation in terms of a guiding intelligence.
Aquinas’ fifth way
- The argument can be put like this:
- The natural world obeys natural laws.
- Natural things flourish as they obey these laws.
- Things without intelligence can’t direct themselves.
- Therefore, things without intelligence require something with intelligence to direct them to their goals.
- This is God.
Test yourself on The Teleological Argument - Aquinas' Fifth Way
What does the ancient Greek word telos mean?