Information = Comprehension × Extension • Comment 2
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https://inquiryintoinquiry.com/2024/10/12/information-comprehension-x-exten…
All,
Let's examine Peirce's second example of a disjunctive term —
“neat, swine, sheep, deer” — within the style of lattice
framework we used before.
❝Hence if we find out that neat are herbivorous, swine are herbivorous,
sheep are herbivorous, and deer are herbivorous; we may be sure that
there is some class of animals which covers all these, all the members
of which are herbivorous.❞ (468–469).
❝Accordingly, if we are engaged in symbolizing and we come to such
a proposition as “Neat, swine, sheep, and deer are herbivorous”,
we know firstly that the disjunctive term may be replaced by
a true symbol. But suppose we know of no symbol for neat,
swine, sheep, and deer except cloven‑hoofed animals.❞ (469).
This is apparently a stock example of inductive reasoning Peirce
is borrowing from traditional discussions, so let us pass over the
circumstance that modern taxonomies may classify swine as omnivores.
In view of the analogical symmetries the disjunctive term shares with the
conjunctive case, we can run through this example in fairly short order.
We have the following four terms.
s₁ = neat
s₂ = swine
s₃ = sheep
s₄ = deer
Suppose u is the logical disjunction of the above four terms.
u = ((s₁)(s₂)(s₃)(s₄))
Figure 2 shows the implication ordering of logical terms in the form of a lattice
diagram.
Figure 2. Disjunctive Term u, Taken as Subject
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https://inquiryintoinquiry.files.wordpress.com/2016/10/ice-figure-2.jpg
Here we have a situation which is dual to the structure of the conjunctive example.
There is a gap between the logical disjunction u, in lattice terminology, the
“least upper bound” of the disjoined terms, u = lub{s₁, s₂, s₃, s₄}, and what
we might regard as the natural disjunction or natural lub of those terms, namely,
v, “cloven‑hoofed”.
Once again, the sheer implausibility of imagining the disjunctive term u would
ever be embedded exactly as such in a lattice of natural kinds leads to the
evident “naturalness” of the induction to the implication v ⇒ w, namely,
the rule that cloven‑hoofed animals are herbivorous.
Reference —
Peirce, C.S. (1866), “The Logic of Science, or, Induction and Hypothesis”,
Lowell Lectures of 1866, pp. 357–504 in Writings of Charles S. Peirce :
A Chronological Edition, Volume 1, 1857–1866, Peirce Edition Project,
Indiana University Press, Bloomington, IN, 1982.
Resources —
Inquiry Blog • Survey of Pragmatic Semiotic Information
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https://inquiryintoinquiry.com/2024/03/01/survey-of-pragmatic-semiotic-info…
OEIS Wiki • Information = Comprehension × Extension
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https://oeis.org/wiki/Information_%3D_Comprehension_%C3%97_Extension
C.S. Peirce • Upon Logical Comprehension and Extension
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https://peirce.sitehost.iu.edu/writings/v2/w2/w2_06/v2_06.htm
Regards,
Jon
cc:
https://www.academia.edu/community/L2E3Bj