Supplement: Oh-oh, I have mixed it completely up. Every implication is a double negation, but not every double negation is an implication, so double negation is the superclass, and thus more primitive than implication.
Just like every kangaroo is a vertebrate, but not every vertebrate is a kangaroo, so vertebrate is the superclass, and more primitive. The first vertebrate is said to have been a fish-like creature with a single spine-bone.
Jon, List,
 
if we distinguish at all between implication and double negation, we are in the field of nonclassical logic. In intuitionalistic logic, every implication is a double negation, but not every double negation is an implication. So implication is the superclass, and double negation the subclass.
the folllowing I derive from Stanley N. Salthe´s paper "Salthe12Axiomathes": In a subsumption (classification), the subclass has inherited the classifying traits from the superclass, and then developed additional traits, that distinguish it from other subclasses of the same superclass. So the subclass is more complex, less primitive than the superclass. So implication is more primitive than double negation, and double negation is derived from implication. But is single negation derived from double negation, or is single negation even more primitive than implication, and is just the combination of two negations derived from implication?
 
Best, Helmut
 
 
08. April 2021 um 02:23 Uhr
"Jon Alan Schmidt" <[email protected]>
wrote:
John, List:
 
JFS: I was just making the point that infants are not born into a paradise.
 
No one is disputing this, including Peirce. What he means by "paradisaical logic" is reasoning without any notion of falsity or operation of negation, the logica utens of a mind that has not yet encountered a reality that clashes with its expectations.
 
JFS: They learn to use the words 'no' and 'not' soon after they begin to utter two or three word sentences.  That is long before they begin to say if-then sentences.
 
This is true but irrelevant. Peirce's point is not about what young children can express, which is a matter of psychology and linguistics; it is about how they reason, which is a matter of logic. No one can learn anything, including the words "no" and "not," without employing the kinds of inferences that we subsequently describe using if-then sentences.
 
JFS: But his metaphor is weird and unconvincing.
 
It is only "weird and unconvincing" if one insists that negation must be more primitive than implication. It makes perfect sense to those who recognize with Peirce that implication is primitive and negation is derived from it.
 
JFS: Why did he feel the need to justify including negation in his logic?
 
He is not justifying the inclusion of negation in his logic, he is explaining that negation is not primitive but must be derived from implication.
 
JFS: What thoughts led him to make negation a primitive in R670? In R670 and L231, he didn't feel any need to justify that choice.  He just showed examples that use negations and nested negations.
 
He decides to simplify his presentation of Existential Graphs to audiences and individuals not previously familiar with them by treating shading for negation as if it were a primitive, rather than spelling out its derivation from implication.
 
Regards,
 
Jon Alan Schmidt - Olathe, Kansas, USA
Structural Engineer, Synechist Philosopher, Lutheran Christian
 
On Tue, Apr 6, 2021 at 11:23 PM John F. Sowa <[email protected]> wrote:

Gary F, Auke, List,

Before commenting on your notes, I want to emphasize that Peirce's paragraph about paradisaical logic in R699 (1911) is a short version of CP 3.488-489, from his Monist article about entitative graphs (written in 1896, published in 1897).  See the copy attached as CP3_488.txt).

GF> are you seriously claiming that an infant’s crying is an instance of logical negation?

No, of course not.  I was just making the point that infants are not born into a paradise.  They have many negative experiences about which they express negative thoughts.  They learn to use the words 'no' and 'not' soon after they begin to utter two or three word sentences.  That is long before they begin to say if-then sentences.

GF> Peirce is using a metaphor to make a point about logic.  He never approved of basing logical principles on psychology.

I agree with both sentences.  But his metaphor is weird and unconvincing.  In the 19th century, every university graduate had studied Aristotle's syllogisms.  Peirce could just give an example to remind his readers that negation is important.

AvB> For me Pierce here hints at the distiction between a logica utens and a logica docens.  It marks the difference between semiosis subject to the normative sciences and semiosis which is not.

That distinction is important.  But in both cases (1896 and 1911), he followed the metaphor with a discussion of negation.  He didn't mention semiosis or the normative sciences.

And by the way, the fact that Peirce used the same weird metaphor in 1991 that he had published in 1897 is significant.  It shows that he must have reviewed his earlier publications about entitative and existential graphs shortly before writing R669.

In any case, I usually find Peirce's examples and metaphors apt and convincing.  But I have no idea why Peirce felt the need for that odd metaphor.  Every logic since Aristotle had negations.  Every logic that Peirce studied since he was 13 had negations.  Why did he feel the need to justify including negation in his logic?  And if so, why did he resurrect an odd metaphor he had used in a different context 15 years earlier?

Thought for the day:  Did Peirce ask himself the same or similar questions during the five days between ending R669 and beginning R670?  What thoughts led him to make negation a primitive in R670? In R670 and L231, he didn't feel any need to justify that choice.  He just showed examples that use negations and nested negations.

John

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