Re: An argument against modus ponens

On Sep 19, 11:01 pm, John Jones <jonescard...@xxxxxxx> wrote:
Doesn't work George. The problem is an old one,

There is no problem whatsoever here, except your refusal to
play the same word-game that everybody else is playing.

but not often talked
about. It's this. What do you identify by the term 'word' in 'these
words'.

We ARE NOT TALKING about words! We ARE NOT TALKING about
natural language! YOU SAID that P didn't have properties, so the
question
RATHER becomes what do YOU identify by P, here? If P is a sentence
then IT DOES have a truth-value! Sentences CAN be true or false!
"It's raining" has a truth-value! "John Jones is not my real name"
has a
truth-value! Sentences USUALLY have truth-values if they are in the
indicative mood
(interrogative, imperative, and exclamatory sentences may fail to have
truth-values,
but those are all FROM NATURAL language, AND WE ARE TALKING ABOUT
FORMAL
languages here)!

Put another way, what exactly is this thing that can be
different things?

Nobody ever said anything could BE different things.
Things can only be what they are. WE are NOT talking about
words in the natural-language sense, OR about the things those words
refer to. WE ARE TALKING ABOUT *STRINGS*.
We are talking about SYMBOLS.
We are talking about FINITE LISTS OF CHARACTERS.
THOSE are our atomic building-blocks around here.

We may also be talking about natural numbers and
THE TWO truth-values as atoms, but because these are abstract,
it is entirely allowable to REPRESENT these AS STRINGS AS WELL.
The number is not (necessarily) the SAME as its numeral, and the
truth-
value is not the same as the symbol or string that names it, BUT THEY
MIGHT AS WELL be; they are both abstract.

And I repeat, this simply is not a problem in the context of a formal
language.
The problem is 1 level lower when you have to somehow convey which of
16 binary boolean functions some string is supposed to "mean" or point
to.
But that is simply NOT A PROBLEM for MOST people; you just handwave
and
keep going. The fact that the argument-lists for these functions are
known to
be two-element lists of truth-values (and the result is also a truth-
value) means that
ANY number of various string-representations of them WILL DO.
.

Relevant Pages

  • Re: An argument against modus ponens
    ... WE'RE SPEAKING natural language (though some of that natural language ... Most sentences in FORMAL languages do not INHERENTLY have any ... ATTRIBUTES truth-values to them: THAT IS WHY THEY ARE CALLED ... The strings we CALL sentences are called THAT, ...
    (sci.logic)
  • Re: An argument against modus ponens
    ... values except in natural language conditions. ... WE'RE IN "natural language conditions". ... Most sentences in FORMAL languages do not INHERENTLY have any ... ATTRIBUTES truth-values to them: THAT IS WHY THEY ARE CALLED ...
    (sci.logic)
  • Re: C Strings
    ... Keith's _completely true_ objection: ... You are very naive about natural language. ... "There is essentially no such thing as a C string". ... interpretation of your statement that is anything other than just ...
    (comp.lang.c)