[FRIAM] talking to bots is fun for everyone

[Frank Wimberly]

I've taken courses in formal logic at multiple levels.  All that notation
is familiar and the explanation seems correct if vacuous.

---
Frank C. Wimberly
140 Calle Ojo Feliz,
Santa Fe, NM 87505

505 670-9918
Santa Fe, NM

On Tue, Dec 27, 2022, 3:19 AM David Eric Smith <desmith at santafe.edu> wrote:

> Interesting.  Lack of global awareness duly noted.
>
> But also, can you check me on this?:
>
> > On Dec 26, 2022, at 7:21 PM, glen <gepropella at gmail.com> wrote:
> >
> > This exchange was interesting. I've never seen ⊃° used.
> >
> > ⋄⋄⋄⋄⋄⋄⋄⋄⋄⋄⋄⋄⋄⋄⋄⋄⋄⋄⋄⋄⋄⋄⋄⋄⋄⋄
> > me: What is the difference between ⊃ and ⊢.
> >
> > gpt: The symbol "⊃" is the logical symbol for "implies." It is used to
> form conditional statements in which the formula on the right is true only
> if the formula on the left is true. For example, the formula "A ⊃ B" can be
> read as "A implies B," and it means that if A is true, then B must also be
> true.
>
> Am I somehow blanking on ordinary sign-flips, or mistaking left and right?
>
> Seems B Is true _if_ A is true.  B is false _only if_ A is false == If A
> is true, then B must also be true.
>
> Given that English is not ensured to have any global internal logical
> consistency, one can see making sentences that don’t close internally.  But
> in areas where English is capable of being used with internal consistency,
> I am surprised to see an “only if” transposed with an “if” everywhere.  Did
> I completely misunderstand what “implies” means?
>
>
> On all this I feel completely exposed: I thought I remembered from Quine’s
> little book on propositional calculus that “implies” isn’t even an
> elementary operator; only enters in a context like modus ponens for
> proofs.  In first-order logic one was supposed to write expressions such as
> “B or not(A)” to mean “if A then B”.  And there was some other symbol (even
> simpler than the entails) for that conditional.
>
> Eric
>
>
>
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