Re: Interpretation of Relations
From: Joe Thurbon <usenet_at_thurbon.com>
Date: Tue, 23 Jan 2007 21:49:52 GMT
Message-ID: <2007012407492922503-usenet_at_thurboncom>
>
> What are A and B ?
>
> Modus ponens is a rule of derivation, a relation between FOL formulas
> (strings of symbols of a certain kind), such that given A and A->B one
> can derive B. There no notion of truth involved in the MP definition.
Date: Tue, 23 Jan 2007 21:49:52 GMT
Message-ID: <2007012407492922503-usenet_at_thurboncom>
On 2007-01-24 00:24:05 +1000, "vc" <boston103_at_hotmail.com> said:
>
> Joe Thurbon wrote:
>> For propositions A and B, modus ponens is a function from
>> AxB -> {true, false}.
>
> What are A and B ?
>
> Modus ponens is a rule of derivation, a relation between FOL formulas
> (strings of symbols of a certain kind), such that given A and A->B one
> can derive B. There no notion of truth involved in the MP definition.
You're right. I stretched the notation and analogy too far. Not any of my A, B, true or false had a concrete meaning anymore. Thanks for pulling me up!
Cheers,
Joe
Received on Tue Jan 23 2007 - 22:49:52 CET