Glenn, Dialectics, 1940
Logic
The art of correct reasoning. Terms, propositions, syllogisms, and the laws of valid argument. The instrument that the other branches use.
Glenn, Dialectics
19 chapters Ch. 0 Ch. 1 Ch. 1 Ch. 1 Ch. 2 Ch. 2 Ch. 3 Ch. 3 Ch. 1 Ch. 2 Ch. 2 Ch. 2 Ch. 1 Ch. 2 Ch. 2 Ch. 2 Ch. 2 Ch. 3 Ch. 0
Introduction to Dialectics
What is Dialectics? Its definition as the science of correct thinking, its formal and material objects, its importance, and its three-part division.
Description and Definition of the Idea
What is an idea? Its description as the mind's grasp of an essence, its formation through abstraction, its constituents (Comprehension and Extension), and its formal definition.
Classification of the Idea
Ideas classified by five aspects: their origin (intuitive or derivative), perfection (clear, distinct, complete), comprehension (simple/compound, concrete/abstract), extension (singular, universal, particular, transcendental), and mutual relations.
The Universal Idea
The Universal idea examined in two aspects: as Reflex Universal (the five Predicables — Species, Genus, Specific Difference, Property, Accident), and as Direct Universal (the ten Categories or Predicamentals).
Definition and Classification of the Term
What is a term? Its definition as a sensible, arbitrary sign that manifests an idea, and its classification by exactness (univocal, equivocal, analogous), by Comprehension, and by Extension.
The Use of the Term
How a term is actually used in context: Supposition (the term taken in a definite sense — material or formal) and Appellation (the application of one term to the reality expressed in another).
Definition
How ideas are explained by defining them: the types of definition (nominal, real essential, descriptive) and the four rules every valid definition must satisfy.
Logical Division
How ideas are explained by dividing them: the doctrine of Logical Division (its three elements — Principle, Totality, Dividing Members) and the four rules that govern a correct division.
The Judgment Itself
The second mental operation: what the Judgment is, how it is defined as the mind's pronouncement on the agreement or disagreement of two ideas, and what its constituent elements are.
Definition of the Proposition
Just as the idea is expressed in the term, the judgment is expressed in the proposition. Its definition, three elements (subject, predicate, copula), logical form, and the properties of quality and quantity.
Classification of the Proposition
The full taxonomy of propositions: simple (A, E, I, O) with the two distribution principles, and compound (modal, categorical, hypothetical, complex, multiple) in all their varieties.
Relative Properties of Propositions
Propositions considered in relation to one another: Opposition (contradiction, contrariety, subcontrariety, subalternity) displayed in the Logical Square; Equipollence; and Conversion — all as means of immediate inference.
Reasoning Itself
The third mental operation: reasoning described as mediate inference, defined in terms of both ideas and judgments, and divided into its two methods — induction (from particular to universal) and deduction (from universal to particular).
The Syllogism and Its Kinds
The syllogism defined, its terms and propositions named, correctness distinguished from truth, and the kinds of syllogism (categorical and hypothetical) enumerated and illustrated.
Laws of the Syllogism
The eight general laws of the categorical syllogism (four laws of terms, four laws of propositions) with reasons and examples; followed by the special laws governing conditional, conjunctive, and disjunctive hypothetical syllogisms.
Figures and Moods of the Syllogism
The four Figures of the syllogism (determined by the position of the middle term), the special laws governing each Figure, and the valid Moods — the 19 combinations of A, E, I, O propositions that survive the laws of syllogism.
Imperfect Syllogisms
Shortened and lengthened forms of the syllogism: the Enthymeme, Epichirema, Polysyllogism, Sorites, and Dilemma; followed by a note on Argument from Analogy and Argument from Hypothesis.
Fallacies to Avoid
The five principal fallacies: Equivocation, Composition and Division, Evading the Point, Begging the Question, and False Cause — with examples and principles for detecting each.
Appendix: On the Reduction of Syllogisms
The complete method for reducing syllogisms of the Second, Third, and Fourth Figures to the First Figure, using the mnemonic Latin names (Barbara, Celarent, etc.) and the reduction consonants s, p, m, c.