The question (15 marks)
Explain what is meant by opposition of propositions, state the four kinds, and set out what may be inferred from the truth and from the falsity of each of A, E, I and O, giving the reason in each case. (15 marks)
MU Module III, head 3.2; pack ch. 09.
Plan your answer on paper before you look at the authorities — issue first, then the rule, then apply it to these facts.
It tests Unit 3 · Inference of Logic – I.
Authorities you will need
- Aristotle, to whom the traditional square of opposition is owed
- Keynes, Formal Logic, on the traditional schedule and on singular propositions
How an answer is marked
A full-marks answer names the issue in one line, states the rule with its section, cites the authority, applies it to these facts and concludes — in that order. The app's model answer for this question is written in exactly that shape, with a checklist to mark your own attempt against.