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Card 4.2 · Root IV — Logic

Informal Logic

Why does formal logic tell you so little about whether an argument is any good?

Informal logic studies reasoning as it occurs in ordinary language, where arguments are incomplete, premises are unstated, and conclusions are supported rather than guaranteed.

From The Coordinates of Thought by Syed Raheel Shahzad, card 4.2, page 189

On this card
  1. Where it sits
  2. The core distinctions
  3. Key figures
  4. Connections
  5. On Coordinates of Thought

Where it sits

Under IV. Logic. Contains 4.2.1 Fallacies, 4.2.2 Argumentation theory, 4.2.3 Rhetoric. Borders 2.6 Rationality, 2.8 Formal epistemology.

Narrower questions under this one:

The core distinctions

DistinctionWhat it separates
Deductive vs defeasibleConclusion guaranteed, against conclusion defeasible by new information
Argument vs explanationEstablishing that something is so, against saying why it is so
EnthymemeAn argument with a premise left unstated because it is assumed
Burden of proofWho must argue, and what the default is if they fail
CharityReading an argument in its strongest available form

Key figures

FigureDatesTraditionContribution
Aristotle384–322 BCEGreekTopics and Sophistical Refutations; dialectical reasoning
The Nyaya schoolc. 2nd c. CE onwardIndianFormal rules of debate; categories of illegitimate move
Stephen Toulmin1922–2009AnalyticA model of argument structure fitting actual practice
Douglas Walton1942–2020AnalyticArgumentation schemes and critical questions

Connections

→ 4.1 · ↔ 4.2.1, 4.2.2, 2.6, 2.7.1 · ◇ informal logic, argumentation theory · ○ Axial Age; Classical; Modern; Table 3

→ narrower questions · ↔ questions it borders · ◇ the positions, mapped in Part III of the book · ○ the eras and comparison tables (Parts IV and V)

The full card is in the book

In The Coordinates of Thought this card goes on to a worked example that sets the answers against one case, and to where the question touches daily life — page 189.

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