Logic Ladder · Middle school · Grade 7–9
Informal Logic
Arguments in everyday words: premises and conclusions, deductive and inductive reasoning, validity and soundness, definitions, and the common fallacies, so you can weigh the reasons you hear.
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Unit 1 Arguments
9 topics
What an argument is, how to find its conclusion and premises, and how to lay it out in standard form or as a map.
Unit 2 Deductive and Inductive Reasoning
9 topics
Two ways reasons can support a claim: validity and soundness for deduction, strength for induction, and how samples, analogies and causes can mislead.
Unit 3 Language and Definitions
6 topics
Clear words make clear arguments: ambiguity and vagueness, kinds of definitions, and how to write and judge a good one.
Unit 4 Fallacies of Relevance
10 topics
Arguments whose premises have nothing to do with the conclusion, though they may stir feelings that make them seem to.
Unit 5 Fallacies of Presumption and Weak Induction
9 topics
Arguments that sneak in an unearned assumption or leap from too little evidence.
Unit 6 Fallacies of Ambiguity
4 topics
Arguments that slide between two meanings of a word, a sentence, or a whole and its parts.
Unit 7 Evaluating Real Arguments
6 topics
Putting it all together: conditional fallacies, telling look-alike fallacies apart, reading charitably, and judging an argument step by step.