Cf: Peirce’s 1870 “Logic of Relatives” • Comment 8.1
https://inquiryintoinquiry.com/2014/02/18/peirces-1870-logic-of-relatives-c…
Peirce’s 1870 “Logic of Relatives” • Comment 8.1
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https://oeis.org/wiki/Peirce%27s_1870_Logic_Of_Relatives_%E2%80%A2_Part_1#C…
All,
To my way of thinking, CP 3.73 is one of the most remarkable passages
in the history of logic. In this first pass over its deeper contents
I won’t be able to accord it much more than a superficial dusting off.
Let us invent a concrete example to illustrate the use of Peirce’s notation.
Imagine a discourse whose universe X will remind us of the cast of characters
in Shakespeare’s Othello.
X = {Bianca, Cassio, Clown, Desdemona, Emilia, Iago, Othello}
The universe X is “that class of individuals about which alone
the whole discourse is understood to run” but its marking out for
special recognition as a universe of discourse in no way rules out
the possibility that “discourse may run upon something which is not
a subjective part of the universe; for instance, upon the qualities
or collections of the individuals it contains” (CP 3.65).
In order to afford ourselves the convenience of abbreviated terms
while preserving Peirce’s conventions about capitalization, we may
use the alternate terms “u” for the universe X and “Jeste” for the
character Clown. This permits the above description of the universe
of discourse to be rewritten in the following fashion.
u = {B, C, D, E, I, J, O}
This specification of the universe of discourse could be
summed up in Peirce’s notation by the following equation.
1 = B +, C +, D +, E +, I +, J +, O
Within this discussion, then, the “individual terms” are as follows.
“B”, “C”, “D”, “E”, “I”, “J”, “O”
Each of these terms denotes in a singular fashion
the corresponding individual in X.
By way of “general terms” in this discussion,
we may begin with the following set.
“b” = “black”
“m” = “man”
“w” = “woman”
The denotation of a general term may be given
by means of an equation between terms.
b = O
m = C +, I +, J +, O
w = B +, D +, E
Resource
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Peirce’s 1870 “Logic of Relatives” • Overview
https://inquiryintoinquiry.com/2019/09/24/peirces-1870-logic-of-relatives-o…
Regards,
Jon