The Five Modes of Agrippa

Agrippa, who was one of the last major Pyrrhonist thinkers in antiquity, developed an elegent set of five modes to supplement the existing Ten Modes of Aensidemus, providing an additional set of methods of examining any belief to identify whether it was unfounded.

1. Dissent – The uncertainty demonstrated by the differences of opinions among philosophers and people in general.
2. Progress ad infinitum – All proof rests on matters themselves in need of proof, and so on to infinity.
3. Relation – All things are changed as their relations become changed, or, as we look upon them from different points of view.
4. Assumption – The truth asserted is based on an unsupported assumption.
5. Circularity – The truth asserted involves a circularity of proofs.