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Leonardi.DB
a logical geometry project

Stoic Sign-Inference and Their Lore of Fate (2024), p. 225
by Schumann, Andrew

Caption

The Stoic square of opposition for opposing two signs 'day', 'night' and two opposing signifieds 'light', 'dark'. There are the following differences from the Aristotelian square: (a) the bottom side of the square represents not a subcontrary relation, but a contradictory (['signified' $\oplus$ 'opposing signified'] $\equiv$ 'true'); (b) two diagonals are to fix not a contradictory relation, but a contrary (['sign' & 'opposing signified'] $\equiv$ 'false'; ['opposing sign' & 'signified'] $\equiv$ 'false'). The rest is the same: (c) the top side of the square is to show a contrary relation (['sign' & 'opposing sign'] $\equiv$ 'false'); (d) the two vertical sides of the square demonstrates a subalternation relation ('sign' $\Rightarrow$ 'signified'; 'opposing sign' $\Rightarrow$ 'opposing signified')

Logic

Aristotelian family
Classical Sigma-2
Boolean complexity
3
Number of labels per vertex (at most)
1
Errors in the diagram
No

Geometry

Shape
Square (regular)
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
none

Edge description

Contains definitions of relations
No
Form
solid lines
,
none
Has arrowheads
No
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
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