Cf: Peirce’s 1870 “Logic of Relatives” • Comment 9.4
https://inquiryintoinquiry.com/2014/02/27/peirces-1870-logic-of-relatives-c…
Peirce’s 1870 “Logic of Relatives” • Comment 9.4
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https://oeis.org/wiki/Peirce%27s_1870_Logic_Of_Relatives_%E2%80%A2_Part_1#C…
All,
Boole rationalizes the properties of what we now call “boolean
multiplication”, roughly equivalent to logical conjunction, in
terms of the laws which govern selective operations. Peirce,
in his turn, taking a radical step of analysis which has seldom
been recognized for what it would lead to, does not consider this
multiplication to be a fundamental operation, but derives it as
a by-product of relative multiplication by a comma relative.
In this way Peirce makes logical conjunction a special case
of relative composition.
This opens up a wide field of inquiry, “the operational significance of
logical terms”, but it will be best to advance bit by bit and to lean on
simple examples.
Back to Venice and the close-knit party of absolutes and relatives
we entertained when last stopping there.
Here is the list of absolute terms we had been considering before:
Figure 1. Absolute Terms 1 M N W
https://inquiryintoinquiry.files.wordpress.com/2022/01/lor-1870-othello-abs…
Here is the list of “comma inflexions” or
“diagonal extensions” of those terms:
1, = anything that is____
= B:B +, C:C +, D:D +, E:E +, I:I +, J:J +, O:O
m, = man that is____
= C:C +, I:I +, J:J +, O:O
n, = noble that is____
= C:C +, D:D +, O:O
w, = woman that is____
= B:B +, D:D +, E:E
One observes the diagonal extension of *1* is
the same thing as the identity relation _1_.
Earlier we computed the following products, obtained by
applying the diagonal extensions of absolute terms to
the same set of absolute terms.
m,n = man that is a noble = C +, O
n,m = noble that is a man = C +, O
w,n = woman that is a noble = D
n,m = noble that is a woman = D
From that we take our first clue as to why the commutative law holds for
logical conjunction. More in the way of practical insight could be had
by working systematically through the collection of products generated
by the operational means at hand, namely, the products obtained by
appending a comma to each of the terms 1, m, n, w then applying
the resulting relatives to those selfsame terms again.
Before we venture into that territory, however, let us equip our intuitions
with the forms of graphical and matrical representation which served us so
well in our previous adventures.
Regards,
Jon