Easy-to-vary failure modes

Week 1: reason · epistemology

Easy-to-vary failure modes

Spot the four classic failure modes: post-hoc, narrow, vague, and empirically equivalent.

In this lesson

  1. Read the core idea (2 min).
  2. Walk through one worked example.
  3. Take the 4-question quiz; pass with 4/4 or better.

Hook

Bad explanations don't fail randomly. They fail in a small number of recognisable ways, and once you can name those failure modes you can spot them in seconds. Most of the time the work isn't deep analysis — it's pattern-matching.

This lesson catalogues the four failure modes you will see most often in real arguments: post-hoc, narrow, vague, and empirically equivalent. Each is a distinct way an explanation can be too easy to vary while looking impressive.