Tom and Pat,
You (both) wrote stuff leading up to Tom's statement:
3) I think Pat offered a
distinction between "exists" and "really exists". This is a
classic move to avoid accepting the conclusion of a specific syllogism; break
the middle term in two.
In the Software Engineering (SE) ontological OO world, the
variables correspond to your quantifiers in logic. Whether any of
those variables influence reality (e.g. through an interface to a
sensor/effector), has little to do with the SE ontology EXCEPT as needed to
interface the device drivers to said real world.
He makes a felicitous
terminological suggestion: associate "ontological commitment" with
"really exists", and commit to it by explicitly using "really
exists" as a predicate. (I think this commits Pat to Anselm's Ontological
Argument, but I'm not sure.)
That's a very effective solution in the Database world where you
could devote a column in the Entities table to store the predicate's value each
time the row is changed and the predicate is reapplied. Low cost, good
performance for most uses.
The other term he offers is
"referential commitment", which he associates with the
"exists" that logicians tie to the "Some" quantifier. And
he explains referential commitment as ontological commitment relativized to a
specified universe of discourse.
Likewise, in the SE world, all commitments relate to the calculation
of those state variables.
That's a very nice move, and
the explanation is persuasive. But it doesn't work for ordinary un-typed FOPL,
since the universe of discourse for that logic (I think) is [Everything that
Exists and Nothing that Doesn't].
I.e., that universe of discourse could be calculated as
everything with the predicate column value = True, and nothing where the predicate
column value = False.
However, perhaps when we talk
about dragons, in natural language, Gricean conventions lead us to a
presupposition of a universe which is not the "real" one", but
is rather the real one supplemented with some fictitious entities (e.g.
Tolkien's universe).
Fantasy and imagination, as well as creative alternatives, are what
makes logic useful. Without it, you may as well use a video.
Sincerely,
Rich Cooper,
Rich Cooper,
Chief Technology Officer,
MetaSemantics Corporation
MetaSemantics AT EnglishLogicKernel DOT com
( 9 4 9 ) 5 2 5-5 7 1 2
http://www.EnglishLogicKernel.com
From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx
[mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of John
Bottoms
Sent: Monday, October 19, 2015 9:43 AM
To: ontolog-forum@xxxxxxxxxxxxxxxx
Subject: Re: [ontolog-forum] Existential Commitment in Logic: a Tabula
Rasa
On 10/19/2015 11:50 AM, Thomas Johnston wrote:
I accidentally deleted the entire thread,
including your responses to my comment of the 18th. So please re-post them.
Nonetheless, this gives me a chance to jump out of the details, and try to see
what the big picture looks like, at this point in the discussion.
1) Quine and most other logicians are find with
associating ontological commitment with the existential quantifier. Arthur Fine
(an outlier on this issue, I would think) prefers to associate ontological
commitment with the universal quantifier. But those quantifiers, as
quantifiers, are associated with "All" and "Some", and so
calling the latter the "existential quantifier" begs the question I
raised.
2) Sometimes, in natural language, we want to say
"All ...." in a context in which we presuppose, and want and believe
others to understand that we are presupposing (cf. Grice), the existence of
what is referenced by the NP of the statement. At other times, we presuppose
that the reference of the NP does not exist, and want and believe others to
understand that we are presupposing that the reference of the NP does not
exist. Same thing for "None ..." statements, same thing for
"Some ..." statements, same thing for "Some ... not"
statements. It was my belief that we want to be able to say all these things in
natural language that led to my original question.
3) I think Pat offered a distinction between
"exists" and "really exists". This is a classic move to
avoid accepting the conclusion of a specific syllogism; break the middle term
in two. He makes a felicitous terminological suggestion: associate
"ontological commitment" with "really exists", and commit
to it by explicitly using "really exists" as a predicate. (I think
this commits Pat to Anselm's Ontological Argument, but I'm not sure.) The other
term he offers is "referential commitment", which he associates with
the "exists" that logicians tie to the "Some" quantifier. And
he explains referential commitment as ontological commitment relativized to a
specified universe of discourse. That's a very nice move, and the explanation
is persuasive. But it doesn't work for ordinary un-typed FOPL, since the
universe of discourse for that logic (I think) is [Everything that Exists and
Nothing that Doesn't]. However, perhaps when we talk about dragons, in natural
language, Gricean conventions lead us to a presupposition of a universe which
is not the "real" one", but is rather the real one supplemented
with some fictitious entities (e.g. Tolkien's universe).
Thomas,
It is best that an ontology is defined for a specific use. There is a vast
difference between the database world and the otherwise closed or fully open
world. In fact, every existence has some scope associated with it. It is just
that it gets ignored or we assume that it is such and such. The "really
exists" is appropriate for an open world application which should also
allow for speculative, fictional and fantasy contexts. That is why, in Euro/US
culture, we tell children "Once upon a time...". We are defining the
context to make it clear and easier for the child or reader to understand the
setting.
If you say "really exists" you are contrasting it with some other
context or scope and the other(s) should be defined. And "really
exists" is from a perspective and therefore subjective, and should have a
frame or facet disclosed as part of that definition. If the context is not
defined for the ontology then we should assume it is...what? Undefined, defined
for closed world, from an unknown POV, or for a fully open world? If there is
not a specified definition then we should not be surprised if there are
miscommunications.
-John Bottoms
Concord, MA USA
4) So I'm ok with this: NPs have referential
commitment no matter what universe of discourse their statements are
relativized to. But NPs have ontological commitment relativized only to
universes of discourse which contain as referents things we believe really
exist. This feels like an elaborate tautology to me, but it's what I make of
Pat's distinction between referential and ontological commitment, and I don't
know any non-tautologous way of stating it.
5) Referential commitment is made with referring
expressions such as names. It is no more closely tied to the "Some"
quantification than it is with the "All" quantification. This seems
obvious to me but, I believe, does not seem obvious to either of you. But
intuitions, expressed as "seems obvious" or otherwise, are not arguments.
FOL, as John said, ain't broke. OK. But I'd add that FOL isn't a Swiss Army
knife. It has limitations, illustrated by the extensive work done on various
forms of intensional logics.
6) Prior to Pat's referential vs. ontological
commitment distinction, I said that I thought ontological commitment could be
made with specific uses of the "All" quantifier, and withheld from
specific uses of the "Some" quantifier. Now I will use Pat's
distinction and say: referential commitment can be made with any NP, regardless
of whether "All" of "Some" is the quantifier used with it.
But this is to rephrase my original intuition, so I suppose that the intuition
you both share is different.
7) I had things I wanted to say about Pat's reply
last night. One I will mention here is that, in my original quotation from the
SEP Ontological Commitment article, I was not trying to pull the wool over
anyone's eyes by leaving off the phrase "According to the third objection
to sufficiency". I realize how lonely it is, where I stand on this, and
never meant to suggest anything else.
8) I am grateful for this extended discussion. I
now have a much better understanding of why I asked the original question, and
where in the beautiful labyrinth of formal logic I might end up (at the Minotaur?)
if I continued down the path of separating commitment from quantification.
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