Argument Analysis: Weakening

Methods in this video

Tap a time to jump to where the video teaches that method.

1. 1

   Same result, a different cause

   ▶ 0:46

   When to use it: Someone takes something they saw or a number (more people hurt at one time of day, a ball returned faster than anyone could react, a high win rate, fewer visitors) and decides what caused it; the question asks what most weakens the argument.

   • Separate what they saw from why they say it happened. The fact can be true while the cause is wrong.
   • Ask what else could cause the same result. For big numbers, check how many took part; for great performances, check opponents, chances and preparation.
   • Pick the option that keeps what they saw and gives it a different cause; one that sounds like a correction but backs them up does not weaken.
2. 2

   Test the reason with a counterexample

   ▶ 4:11

   When to use it: The key reason is a general statement (space research does nothing for life on Earth, a good gardener needs no help to name plants, pets are forced to perform, over time glass flows downwards); the question asks what most weakens the argument.

   • Shrink the key reason to one sentence and circle words like nothing, without and all.
   • Find a case of the same kind that does not fit. One real counterexample is enough; so is a missing result where his cause should show most.
   • Watch for options that help him: criticising the other side's tool, a same-direction comparison, or a benefit that lands somewhere else.