Method?

The reasoning check.

The method ladder grades the evidence. The reasoning check looks at the step from evidence to conclusion, and names the logical fallacies it finds there. Wherever you see the red query mark, a fallacy has been diagnosed. Click it for the definition.

Clear case. The inference, as made, depends on it. Possible. At risk, depending on how the argument is read or completed.

How we diagnose

  • Both readings, the same testsEvery claim card checks the claim as taught and the alternative reading the site offers. Each fallacy page gives one example from each side.
  • The strongest version firstA fallacy is diagnosed only when the argument still depends on it after it has been read as charitably as possible.
  • A fallacy is not a refutationA conclusion can be true even when an argument for it is bad. The check says whether this argument, as made, supports its conclusion. Treating a named fallacy as proof that the conclusion is false is itself a fallacy.
  • Every label says when it isn't oneMost of these moves are legitimate in some form. Each page says where the line falls, so you can check our judgment.

The catalogue

Ambiguity  · A word or idea shifts meaning partway through the argument.
  • EquivocationOne word carries two meanings, and the argument slides from one to the other.Diagnosed 6× on this site
  • ReificationAn abstraction is spoken of as if it were an agent that can choose, design or invent.Not yet diagnosed
Form  · The argument's structure does not deliver its conclusion, even if every premise is true.
  • Affirming the consequentIf H, then we'd see E. We see E. So H. This only works if no rival explanation also predicts E.Diagnosed 10× on this site
Presumption  · The argument assumes something it has not shown, sometimes the very thing in question.
  • Begging the questionThe conclusion is already built into one of the premises.Diagnosed 2× on this site
  • False dilemmaOnly two options are offered when others exist.Not yet diagnosed
  • Hidden theological premiseA scientific-sounding argument depends on an unstated claim about what God would or would not do.Not yet diagnosed
Induction  · The evidence is real, but too narrow or too selected to carry the general conclusion.
  • Unwarranted extrapolationA process seen working on a small scale is assumed to work on a far larger one, without evidence that it can.Diagnosed 7× on this site
  • Cherry-pickingThe evidence that fits is shown, and the evidence that doesn't is left out.Diagnosed 4× on this site
Testability  · The explanation is shielded from any result that could count against it.
  • Just-so storyA plausible story of how something came about is offered as the explanation, without independent tests.Diagnosed 1× on this site
  • Ad hoc rescueWhen a prediction fails, an extra assumption is added whose only job is to save the theory.Diagnosed 6× on this site
Ignorance  · What we don't know, or can't imagine, is treated as evidence.
Relevance  · Something other than the evidence is doing the persuading.
  • Appeal to consensusA claim is presented as settled because most experts accept it, in place of the evidence.Not yet diagnosed
  • Genetic fallacyAn argument is judged by who makes it, or where it comes from, rather than by its merits.Not yet diagnosed
  • Straw manThe other side's position is restated in a weaker form, and the weaker form is refuted.Not yet diagnosed

The Evidence Evaluator will apply the same catalogue to any paper, article or video you bring it.