Re: An argument against modus ponens

george wrote:
On Sep 10, 2:40 pm, John Jones <jonescard...@xxxxxxx> wrote:
Objects don't have properties of truth and falsehood.

They do IN LOGIC, DUMBASS.

No they don't. Objects don't have properties of truth and falsehood. Truth and falsehood are functions not of objects but on the frameworks within which objects are presented.

The whole enterprise IS ABOUT truth and falsehood.

No it isn't. "P" states P. Period.

Of course, in first-order logic, we do generally distinguish between
"first-class" objects AND SENTENCES, and it is the latter that
must have truth or falsehood, while the former usually don't.

No. Neither sentences nor objects in logic have properties of truth and falsehood. Sentences and objects are either presented or not. Their truth and falsity is a function of the framework within which they are presented.

But in the extended sense in which YOU are using "object"
(you are calling P an object, whereas people WITH a brain would
call P a proposition -- that' s *why* "P" is chosen as a name for it),
propositions and/or boolean variables MUST have truth-values.

No. Whether P is a proposition or an object is immaterial. That's my whole point - in a non-anthropomorphic, true, logic, P is P. Period. Forget the airy fairy 'oh its a sentence', 'oh its an object', 'oh but what would my grandmother think' sweat the small stuff.
.

Relevant Pages

  • OT: Truth and imagination
    ... No, right and wrong are moral determinations, truth and falsehood ... neither did we make war on and invade Iran. ... terrorists, who are terrorist sympathizers, who are terrorist ...
    (comp.sys.hp.mpe)
  • Re: IS the "Clergy Letter" an indication of OKIMOTOS profession of
    ... different order from scientific truth. ... We the undersigned, Christian clergy from many different traditions, ... modern science may comfortably coexist. ... they are promoting a falsehood when they claim ...
    (talk.origins)
  • Re: Re: David Duke ought to be shot.
    ... What he's telling his followers is that the Euro dollar ... he tells the truth on some occasions it is only for the purpose of ... deliberate falsehood. ... The Jew is the Great Master of Lies. ...
    (alt.politics)
  • Re: Re: Re: Re: Re: > Iranian Scuzzy Muzzy Nuke Scientist Says Weekend Quake was a Nuclear Test
    ... Here are some quotes from Mein Kampf: ... he tells the truth on some occasions it is only for the purpose of ... deliberate falsehood. ... The Jew is the Great Master of Lies. ...
    (alt.politics)
  • Re: Re: Freepers, Nazis take over MSNBC poll
    ... he tells the truth on some occasions it is only for the purpose of ... deliberate falsehood. ... The Jew is the Great Master of Lies. ... combat this mortal enemy of our people, who is at the same time the ...
    (alt.politics)