SYNOPSIS

The author of the "Xiao Qu" chapter of the Mo Zi seems to me to make three main points about the correct use of language and its connection to logic. These three points are covered in succeeding sections of the chapter:

Section II On the Irrelevance of Accidental Qualities

being a slave --> being a human. 是而然
S H S --> H
1 1 1 Paradigmatic case: S = 1 H = 1
1 0 0 Contrary case: S = 1 H = 0
0 1 1 "是而然" indicates that when the
0 0 1 antecedents and consequents are
instanced the implication is true

Section III On the Relevance of Differentiae*

~(being a Bandit --> being Human) 是而不然
B H ~(B --> H)
1 1 0 paradigmatic case: B=1, H=0
1 0 1 contrary case: B=1, H=1
0 1 0 "是而不然" indicates that were the
0 0 0 antecedents and consequents both
instanced then the implication would
be shown false.

SECTION IV On Anti-fatalism

~approaching well --> ~falling in well. 不是而然
A F ~A --> ~F
1 1 1 paradigmatic: A=0, F=0
1 0 1 countercase: A=0, F=1
0 1 0 "不是而不然" indicates that were
0 0 1 neither antecedent nor consequent
instanced then the implication
would be shown true.

* A more down-to-earth example of type III:
~(thriving on Mushrooms --> thriving on Toadstools)
M T ~(M --> T)
1 1 0
1 0 1
0 1 0
0 0 0

We do not know that if an organism thrives on mushrooms it will also thrive on toadstools (or, fungi in general). We know of an organism that thrives on a subset of fungi, mushrooms, but not on all fungi. So we assert that it is not the case that if an organism thrives on mushrooms it will (necessarily) thrive on toadstools (or, fungi in general). (I don't know a word that includes just mushrooms and toadstools.)