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Single Idea 15879

[filed under theme 4. Formal Logic / A. Syllogistic Logic / 2. Syllogistic Logic ]

Full Idea

Square of Opposition: 'all A are B' and 'no A are B' are contraries; 'some A are B' and 'some A are not B' are sub-contraries; the pairs 'all A are B'/'some A are B' and 'no A are B'/'some A are B' are contradictories.

Gist of Idea

The Square of Opposition has two contradictory pairs, one contrary pair, and one sub-contrary pair

Source

Rom Harré (Laws of Nature [1993], 3)

Book Ref

Harré,Rom: 'Laws of Nature' [Duckworth 1993], p.62

A Reaction

[the reader may construct his own diagram from this description!] The contraries are at the extremes of contradiction, but the sub-contraries are actual compatible. You could add possible worlds to this picture.

Related Idea

Idea 9405 Square of Opposition: not both true, or not both false; one-way implication; opposite truth-values [Aristotle]

The 27 ideas from Rom Harré

15869 Reports of experiments eliminate the experimenter, and present results as the behaviour of nature [Harré]
15868 Idealisation idealises all of a thing's properties, but abstraction leaves some of them out [Harré]
15860 We take it that only necessary happenings could be laws [Harré]
15867 Laws describe abstract idealisations, not the actual mess of nature [Harré]
15864 Classification is just as important as laws in natural science [Harré]
15865 Newton's First Law cannot be demonstrated experimentally, as that needs absence of external forces [Harré]
15862 Laws can come from data, from theory, from imagination and concepts, or from procedures [Harré]
15870 Are laws of nature about events, or types and universals, or dispositions, or all three? [Harré]
15871 Are laws about what has or might happen, or do they also cover all the possibilities? [Harré]
15872 Must laws of nature be universal, or could they be local? [Harré]
15875 In counterfactuals we keep substances constant, and imagine new situations for them [Harré]
15876 Maybe laws of nature are just relations between properties? [Harré]
15874 Scientific properties are not observed qualities, but the dispositions which create them [Harré]
15879 The Square of Opposition has two contradictory pairs, one contrary pair, and one sub-contrary pair [Harré]
15881 We can save laws from counter-instances by treating the latter as analytic definitions [Harré]
15882 Since there are three different dimensions for generalising laws, no one system of logic can cover them [Harré]
15878 Some quantifiers, such as 'any', rule out any notion of order within their range [Harré]
15880 In physical sciences particular observations are ordered, but in biology only the classes are ordered [Harré]
15885 The necessity of Newton's First Law derives from the nature of material things, not from a mechanism [Harré]
15884 Laws of nature remain the same through any conditions, if the underlying mechanisms are unchanged [Harré]
15886 Science rests on the principle that nature is a hierarchy of natural kinds [Harré]
15889 It is because ravens are birds that their species and their colour might be connected [Harré]
15890 Non-black non-ravens just aren't part of the presuppositions of 'all ravens are black' [Harré]
15887 'Grue' introduces a new causal hypothesis - that emeralds can change colour [Harré]
15891 Traditional quantifiers combine ordinary language generality and ontology assumptions [Harré]
15888 The grue problem shows that natural kinds are central to science [Harré]
15892 Laws of nature state necessary connections of things, events and properties, based on models of mechanisms [Harré]