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Logic I · Unit 2

Propositions

Unit 2 of Logic – I (syllabus: Module II — proposition, sentence, judgment and fact; constituents and the copula; the traditional classification and distribution of terms; reducing sentences to logical form; the modern classification and general propositions). Below: what the unit covers, the provisions it turns on, and the cases an examiner expects you to name.

What this unit covers

  • What is a proposition, and how does it differ from a sentence, a judgment and a fact?
  • What is the copula, and why is the traditional analysis of proposition defective?
  • How are propositions classified by quality and quantity into the fourfold scheme?
  • When is a term distributed, and what governs distribution?
  • How is a sentence reduced to its logical form?
  • How does the modern classification divide propositions, and on what test?
  • What are the truth conditions of the five kinds of compound proposition?
  • How are the four traditional forms symbolised in modern logic, and what does the symbolisation show?
  • Where do the traditional and the modern classifications genuinely disagree?

Treat that list as a self-test: recite each topic's rule from memory before you open its cases.

Provisions

  • Proposition, sentence, judgment and fact distinguished, s. Module 2, head 2.1
  • Meaning of predication with special reference to the copula, s. Module 2, head 2.10
  • Traditional classification: the fourfold classification of propositions, s. Module 2, head 2.2
  • Distribution of terms in A, E, I and O propositions, s. Module 2, head 2.4
  • Reduction of sentences to their logical forms, s. Module 2, head 2.3
  • Modern classification of propositions: kinds of simple and compound propositions, s. Module 2, head 2.6
  • Basic truth tables for compound propositions, s. Module 2, head 2.6
  • General propositions in modern logic: universal and existential propositions, s. Module 2, head 2.7
  • Comparative study of the traditional and modern classifications, s. Module 2, heads 2.8 and 2.9

Leading cases

  • Cohen and Nagel
  • Aristotle
  • Kant
  • Keynes
  • Aristotle for the traditional reading; the modern reading is the one set against it

Exam questions on this unit