Logic Ladder · High school · Grade 8–10
Traditional Logic
The logic of Aristotle and the classical schools: terms, the four categorical propositions, the square of opposition, immediate inference, syllogisms tested by rules and Venn diagrams, and hypothetical and disjunctive reasoning.
0 of 48 topics passed
Unit 1 Terms and Simple Apprehension
6 topics
The first act of the mind: grasping what a thing is. Terms, extension and comprehension, genus and species, the predicables, and logical division.
Unit 2 Categorical Propositions
7 topics
The second act of the mind: judgment. The four standard forms A, E, I and O, translation into standard form, distribution, Venn diagrams and existential import.
Unit 3 The Square of Opposition
6 topics
How the four forms about the same subject and predicate constrain one another: contradictories, contraries, subcontraries and subalterns.
Unit 4 Immediate Inference
5 topics
New propositions from a single one: complements, conversion, obversion and contraposition, and chains of them.
Unit 5 Categorical Syllogisms
11 topics
The third act of the mind: reasoning. Terms, mood and figure, testing by Venn diagrams and by the rules, and the valid forms.
Unit 6 Syllogisms in Everyday Form
4 topics
Real arguments rarely arrive in standard form: reducing the number of terms, translating, filling in enthymemes, and chains called sorites.
Unit 7 Hypothetical and Disjunctive Syllogisms
9 topics
Reasoning with if, or and not both: modus ponens and tollens, their fallacies, pure hypothetical, disjunctive and conjunctive syllogisms, and dilemmas.