Introduction (2015), p. 33
by Read, Stephen

Copyright according to our policy

Caption

Buridan’s Modal Octagon (From MS Vatican Pal.lat. 994 f. 11v, reproduced with permission of Biblioteca Apostolica Vaticana)

Logic

Aristotelian family

Buridan Sigma-4

Boolean complexity

6

Number of labels per vertex (at most)

9

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

0–2

Coplanarity range

0

Cospatiality range

0

Representation of contradiction

By central symmetry

Vertex description

Conceptual info

No

Mnemonic support (AEIO, purpurea ...)

No

Form

rectangular

Label type

linguistic

Language

Latin

Lexical field

modal syllogistics

Contains partial sentences or single words

No

Contains abbreviations

Yes

Edge description

Contains definitions of relations

No

Form

bands

Has arrowheads

No

Overlap

Yes

Curved

No

Hooked

Yes

As wide as vertices

No

Contains text

Yes

Label type

linguistic

Language

Latin

Contains partial sentences or single words

No

Contain abbreviations

Yes

Style

Diagram is colored

No

Diagram is embellished

No

Tags

duality

Is a reproduction of

Buridan, John. 1301–1400. Summulae de Dialectica. Vatican City: Biblioteca Apostolica Vaticana. (fol. 10v)