Lesson · 4 min Stretch
The Five Modes
In one line Defending a claim runs into disagreement, regress, relativity, assumption or a circle. Know which one you hit.
A later skeptic named Agrippa, known only through other writers, left five modes, or patterns, that bring a claim to suspension. Sextus records them. They are a toolkit for asking how a belief is supported.
Disagreement: thoughtful people differ on the question. Regress: each reason needs another reason, without end. Relativity: things appear one way to one observer and another way to another. Hypothesis: the chain stops at an assumption simply laid down. Circularity: the support for a claim quietly depends on the claim itself.
Agrippa’s point is that attempts to justify a belief seem to end in one of these. Philosophers still discuss the problem as Agrippa’s trilemma, built from regress, assumption and circle. The habit worth keeping is to see where your own reasons run out.
Go deeper
Modern answers to the regress take three main shapes. Foundationalists say some beliefs, such as plain perceptions, need no further reason. Coherentists say beliefs support each other in a web, so a large circle is not vicious. Infinitists accept an endless chain of reasons. Each answer has critics, which is itself a fair illustration of Agrippa’s first mode.
Why trust the map?
Jon tells a friend the trail is safe because the map says so. Why trust the map? Because the park made it. Why trust the park? Because its maps have been right. How does he know? Because the map shows no washouts.
Jon laughs when he hears himself. His reasons have looped back to the map. He calls the ranger station to get support from outside the circle.
Try this today Take one belief you hold firmly and ask for its reason three times. Note where the chain stops.
Cite or share this lesson
A plain reference you can paste into notes or an essay:
Quest2Reason. “The Five Modes.” https://quest2reason.com/learn/lesson/the-five-modes. Accessed 13 November 2026.
Sources
- Stanford Encyclopedia of Philosophy, “Ancient Skepticism” — Covers Pyrrho, the Pyrrhonist revival, the Academic skeptics and the modes of Agrippa.
- Internet Encyclopedia of Philosophy, “Ancient Greek Skepticism” — Sets out the five modes and the debate over whether a skeptic can live without beliefs.
- Sextus Empiricus, Outlines of Pyrrhonism, Book I, sections 164 to 177 — The five modes of Agrippa as Sextus records them. Paraphrased; no translation is quoted.