Reasoning Lab — Argument Editor

Natural-deduction proofs, one checked step at a time — propositional and first-order.

Any propositional formula, every row, with tautology and contradiction flagged.

Mood, figure, and validity for a categorical syllogism, on both readings.

Two- and three-circle diagrams for categorical claims and set relations.

Which terms an A, E, I, or O statement distributes, and why.

Paste a passage; name its conclusion and premises with indicator-word help.

Numbered premises above a line, conclusion below — the form every evaluation starts from.

A visual map of premises, sub-conclusions, and the support between them.

Diagnose a weak argument and rebuild it stage by stage.

Do the reasons bear on the conclusion, and are they enough?

Fourteen informal-fallacy checks, then a guided repair.

Genus, differentia, and boundary cases — with the classic definition faults checked.

Eight tests against examples, non-examples, and borderline cases.

Score rival hypotheses on the explanatory virtues.

Mill's methods over a table of cases.

Rate a generalization or analogy on the criteria that decide its strength.

Prior, likelihoods, posterior — with the base-rate trap made visible.

Twelve short animated walkthroughs of central concepts, from deduction to decision theory.