Jerry, List:

JLRC: The classical logic of mathematical reasoning (symbolized by five
signs - negation, conjunction, disjunction, material conditional, and
bi-conditional.


Actually, Peirce points out that only two signs are needed as primitives,
with the others being derived from them.

CSP: Out of the conceptions of non-relative deductive logic, such as
consequence, coexistence or composition, aggregation, incompossibility,
negation, etc., it is only necessary to select two, and almost any two at
that, to have the material needed for defining the others. What ones are to
be selected is a question the decision of which transcends the function of
this branch of logic. (CP 2.379, 1902)


For example, in the Alpha part of Existential Graphs for propositional
logic, the simplest approach is to select the two primitives as
juxtaposition for conjunction (coexistence) and shading for negation* such
that disjunction is then defined as multiple unshaded areas within a shaded
area, material conditional (consequence) as one unshaded area within a
shaded area (scroll), and bi-conditional as juxtaposed scrolls with the
antecedent and consequent reversed. The Beta part for first-order predicate
logic adds one more primitive, the line of identity for existential
quantification such that universal quantification is then defined as a line
of identity whose outermost part is within a shaded area.

*As I have discussed on the List many times before, although this choice is
practically more efficient and easier to explain, Peirce suggests on
several occasions that it is philosophically more accurate to select the
scroll for material implication as the second primitive such that negation
is then defined as a scroll with a blackened inner close shrunk to
infinitesimal size, signifying that *every *proposition is true if the
antecedent is true (CP 4.454-456, 1903; CP 4.564n, c. 1906; R 300:[47-51],
1908; R 669:[16-18], 1911).

Regards,

Jon Alan Schmidt - Olathe, Kansas, USA
Structural Engineer, Synechist Philosopher, Lutheran Christian
www.LinkedIn.com/in/JonAlanSchmidt / twitter.com/JonAlanSchmidt

On Thu, Jan 11, 2024 at 12:52 PM Jerry LR Chandler <
jerry_lr_chand...@icloud.com> wrote:

> On Jan 11, 2024, at 11:28 AM, Edwina Taborsky <edwina.tabor...@gmail.com>
> wrote:
>
> But  you already know this
>
> Edwinia:
>
> If I understood the meaning of the “triadic relations”, I would not waste
> my time attempting to frame precise questions and intensely analyzing the
> grammatical structures of your and other responses.
>
> Mathematical reasoning is grounded in set theory - the relation between 
> *ordered
> pair*s.
>
> The classical  logic of mathematical reasoning (symbolized by five signs -
> negation, conjunction, disjunction, material conditional, and
> bi-conditional.
>
> These signs are often interpreted in terms of the Aristotelian
> syllogisms.  Which in turn, are related to sentences and sentence
> grammars.  For a discussion of Peircian *“tokens and types” *from a
> categorical perspective, see the recent text by Ursula Skadowski, Logic -
> Language - Ontology. 2022.
>
> Or, asserted in similar terms, is the meaning of a triadic relation
> constrained to multi-valued logics?
>
> My interpretation of the posts by the John / Jon / Robert posts is that
> the classical logic for deduction preserves the truths of propositions of
> molecular sentences.  (Note, it was not necessary to invoke either Robert
> Rosen’s writings on the philosophy of science or thermodynamics or entropy
> or dogmas or….  Just seeking a scientifically useful meaning for my
> research.
>
> Cheers
> Jerry
>
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