Date: Thu, 10 Jul 2008 21:54:25 -0400
"JOG" <jog_at_cs.nott.ac.uk> wrote in message news:08598487-a4c2-4787-9381-8784125eb288_at_y38g2000hsy.googlegroups.com...
> On Jun 22, 5:51 am, "Brian Selzer" <br..._at_selzer-software.com> wrote:
>> "paul c" <toledoby..._at_ac.ooyah> wrote in message
>> > Brian Selzer wrote:
>> >> "paul c" <toledoby..._at_ac.ooyah> wrote in message
>> > ...
>> >>>> ... In a first order language, you have constant symbols and
>> >>>> predicate symbols, and under an interpretation, meaning is assigned
>> >>>> not
>> >>>> only to the constant symbols but also to the predicate symbols. The
>> >>>> way I see it, the only way you can have overlapping meanings is if a
>> >>>> relation has a disjunctive predicate. ...
>> >>> Not sure if that's so, but willing to assume it is for now. It
>> >>> reminds
>> >>> me that I have doubts about whether any relation should be allowed to
>> >>> disjunctions within individual propositions, at least if we want
>> >>> 'interchangeability'. For example, a base relvar that has been
>> >>> inserted
>> >>> to with "union" certainly doesn't have a disjunctive predicate so why
>> >>> should a view that is manifested the same way be different?
>> >> Because one involves two database states and the other involves only
>> >> one.
>> >> Any mutating operation necessarily involves two database states (or
>> >> instances, or values--whichever nomenclature you prefer): there is
>> >> what
>> >> was then supposed to be the case and what is now supposed to be the
>> >> case.
>> >> But a view simply presents information contained in one database
>> >> state--what is now supposed to be the case--in a different way. The
>> >> connection between what is presented by a view and what is in the
>> >> underlying relations is the expression that defines the view. If that
>> >> happens to be a union, then the predicate of the view is the
>> >> disjunction
>> >> of the predicates of the two operands of the union. This is
>> >> inescapable.
>> >> ...
>> > One may choose one's starting point so as to conclude that it is
>> > 'inescapable' (sorry, not trying to mimic Bob B's high tones), but I
>> > feel
>> > that escape from this consequence is rather necessary!
>> Why is it necessary?
>> > (seems a pedantic consequence to me which usually signals to me that
>> > something basic is just wrong, also I'm not saying I have the IQ
>> > wherewithal to show how, but am wondering whether a more complete POOD
>> > might argue that the presence of any non-disjunctive tuple in a db, no
>> > matter whether it's in a base or 'virtual' relation, trumps any
>> > disjunctive operator that might have produced/manifested it.)
>> Consider the following statements:
>> 1. Susan is an electrical engineer.
>> 2. Susan is a mechanical engineer.
>> 3. Susan is an electrical engineer or Susan is a mechanical engineer.
>> Now, suppose you have a base relation P whose members map to individuals
>> that exemplify the property of being an electrical engineer, a base
>> Q whose members map to individuals that exemplify the property of being a
>> mechanical engineer, and a virtual relation (a view) R (P UNION Q) whose
>> members map to individuals that exemplify either the property of being an
>> electrical engineer or the property of being a mechanical engineer or
>> The presence of a tuple in the virtual relation with a value that maps to
>> Susan tells us only that Susan exists and that she is either an
>> engineer or a mechanical engineer or both. It does not tell us which.
>> is only the fact that the value that maps to Susan appears also in both
>> the base relations that tells us that in fact Susan is both an electrical
>> engineer and a mechanical engineer. So here we have three relations, two
>> base, one derived, that draw their values from the same domain, but it is
>> where a particular value appears that imparts different aspects of
>> to that value.
> > Values don't have meaning. That would indicate they somehow > "contained" that meaning. Meaning is conferred upon values by > isolation of the context in which they have been described (here the > relation they are contained in and its associated predicate), followed > by interpretation of that description by a human (with their > subjective understanding of the world). >
I'm not sure I agree. Symbols don't have meaning apart from interpretation. Nor do combinations of symbols. Consider the combination MIX:
Does it represent the act of combining things? Is it a representation of the number 1009? Is it the name of Donald Knuth's mythical computer?
Only under an interpretation is an instance of that particular combination of symbols assigned meaning. And when a symbol or combination of symbols has been assigned meaning, the object in the universe that it maps to is the value it is associated with. A value, therefore, is in a very strict sense what a symbol means. So you're right in saying that it doesn't /have/ meaning or /contain/ meaning: it is what is meant.
> I recommend reading Wittgenstein's "Philosophical Investigations", > Dreyfus' "What Computers still can't do" and Clancey's "Situated > Cognition" for related analyses. Better to stand on the shoulders of > giants than the toes of midgets I say. >
Here's a quote from Wittgenstein's /Philosophical Investigations/. Page 2 in fact:.
These words [a quote from Augustine, /Confessions/], it seems to me, give us a particular picture of the essence of human language. It is this: the individual words in language name objects--sentences are combinations of such names.--in this picture of language we find the roots of the following idea: Every word has a meaning. This meaning is correlated with the word. It is the object for which the word stands. <<<
Funny how the first recommended reading supports my position in just the first few pages. To be sure, Wittgenstein argues that words have meaning, and they do, but not until it has been assigned under an interpretation. Nevertheless, the object that a symbol maps to is the value correlated with that symbol, and is per Wittgenstein, what is meant.
>> Note that there is no overlap in meaning for relations P and
>> Q--even though they draw their values from the same domain: whether an
>> individual is an electrical engineer or not has no bearing whatsoever on
>> whether that individual is a mechanical engineer or not.
> Received on Thu Jul 10 2008 - 20:54:25 CDT