Definition of subcontrary in English:

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Pronunciation: /sʌbˈkɒntrəri/
Logic , dated


Denoting propositions which can both be true, but cannot both be false (e.g. some X are Y and some X are not Y).
Example sentences
  • Similarly, ‘some unicorns have horns’ and ‘some unicorns do not have horns’ are both regarded as false, and so they are not subcontrary.’
  • Paradox seems to arise when conditional statements have subcontrary statements as antecedent and consequent.
  • It follows that high or low probability are contrary to necessity of opposite polarity, and subcontrary to possibility of opposite polarity.

noun (plural subcontraries)

A subcontrary proposition.
Example sentences
  • Again, I and O propositions are subcontrary, but not contrary or contradictory.
  • The case of subcontraries will be revealed to include an unjustified presupposition in the section concerning the modern square of opposition.
  • Given that traditional logicians did think the subcontraries have ‘existential import’, how do we resolve the apparent contradiction?


Late 16th century: from late Latin subcontrarius, translation of Greek hupenantios.

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