Propositional attitudes (2001), p. 236
by Davies, Eirian

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Caption

Square of opposition 1.2

Logic

Aristotelian family

Classical Sigma-2

Boolean complexity

3

Number of labels per vertex (at most)

3

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 central symmetry

Vertex description

Conceptual info

Yes

Mnemonic support (AEIO, purpurea ...)

No

Form

none

Label type

linguistic

,

symbolic

Language

English

Lexical field

verbs

Contains partial sentences or single words

Yes

Contains abbreviations

No

Symbolic field

logic

Contains partial formulas or symbols

No

Edge description

Style

Diagram is colored

No

Diagram is embellished

No

Additional notes

The formulas are encoded using a bitstring/setting-like approach, with 9 bit positions (cf. p. 228):

t = is
r = must be
s = will be
q = would be
w = (equiprobability)
u = wouldn't be
n = won't be
a = can't be
f = isn't