Deontic reasoning reviewed: psychological questions, empirical findings, and current theories (2010), p. 124
by Beller, Sieghard

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Caption

The deontic square of oppositions

Logic

Aristotelian family

Classical Sigma-2

Boolean complexity

3

Number of labels per vertex (at most)

2

Equivalence between (some) labels of the same vertex

Yes

Analogy between (some) labels of the same vertex

No

Uniqueness of the vertices up to logical equivalence

Yes

Errors in the diagram

No

Geometry

Shape

Rectangle (irregular)

Colinearity range

0

Coplanarity range

0

Cospatiality range

0

Representation of contradiction

By some other geometric feature

Vertex description

Conceptual info

No

Mnemonic support (AEIO, purpurea ...)

No

Form

rectangular

Label type

linguistic

Language

English

Lexical field

deontic operators

Contains partial sentences or single words

Yes

Contains abbreviations

No

Edge description

Style

Diagram is colored

No

Diagram is embellished

No