- Aristotle's theory can be defended because it is made up from his studies of the natural world, reliable.
- Strong compared to Plato's forms which are not observable in the physical world.
- The four causes can be applied to things that exist within the world as a way of explaining them.
- There are no anomalies to contradict the argument so not much opposition e.g. God or the big bang.
- Rely on experience. this is unreliable because experience changes from person to person(We cannot be sure that chairs look the same to every person)
- Has no concrete evidence that the material world is the source of knowledge.
- Perhaps things don't exist for a reason, some things happen by chance. For example, Bertrand Russell said "The universe is just here, and that's all".
- if the prime mover cannot interact with the world, it is very different from the Judaeo-Christian understanding of God.