Why Care beyond the Square? Classical and Extended Shapes of Oppositions in Their Application to "Introspective Disputes" (2017), p. 334
by Fink, Sascha Benjamin

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Caption

Buridan's octagon of opposition, applied to an exemplary introspective dispute

Legend

Logic

Aristotelian family

Buridan Sigma-4

Boolean complexity

6

Number of labels per vertex (at most)

1

Uniqueness of the vertices up to logical equivalence

Yes

Errors in the diagram

No

Geometry

Shape

Octagon (irregular)

Colinearity range

0

Coplanarity range

0

Cospatiality range

0

Representation of contradiction

By central symmetry

Vertex description

Conceptual info

No

Mnemonic support (AEIO, purpurea ...)

No

Form

circular

Label type

linguistic

,

philosophical theories

Language

English

Lexical field

syllogistics

Contains partial sentences or single words

No

Contains abbreviations

No

Edge description

Contains definitions of relations

No

Form

solid lines

,

none

,

dashed lines

Has arrowheads

Yes

Overlap

No

Curved

No

Hooked

No

As wide as vertices

No

Contains text

No

Label type

none

Style

Diagram is colored

No

Diagram is embellished

No