Dear Matthew, Thomas, John, ...
TJ> I have proposed a third temporal dimension -- that in which the
statements made by rows in tables are asserted to be true. For example, a
logically deleted row remains in a database as one which no longer represents
the assertion of the statement it makes. And just as we can utter/write
statements (de-indexicalized declarative sentences) that, starting at some
point in time, we are no longer willing to assert represent statements we
believe are true, so too we can enter rows into database tables that represent
statements that we are not yet, at that time, willing to assert represent true
statements. The former rows are tagged with "speech act" time periods
(see below) that are entirely in the past, and the latter with time periods
that are entirely in the future. Again, this is not in the current SQL
standard, nor in the current comp sci literature.
[MW>]
I’m still not clear (but interested).
RC> I think you are describing what is best represented as fluents in
the table. A "fluent" row comprises the predicate's specified value
of true or false, and its parametric bindings to objects and properties. But the
fluent row also stores the truth value that this row currently represents -
i.e., true or false. For example:
_a^2 + _b^2 = _c^2
is the 90 degree triangle Pythagorean constraint on the length
of the three sides. To determine if the Pythagorean constraint is true, we
need values for _a, _b and _c to check the equation. But we can also store the
truth value _tf with the value of a given triangle we wish to store in the
knowledge base. So the database record would be:
< _tf : Boolean; _a : number; b: number; c : number
>
Then, given instance values for a, b and c to ground _a, _b and
_c, the Pythagorean constraint on that instance would be evaluated true or
false. That evaluation, compared with the stored value _tf, would drive an
application's interpreted decision to assert that the instance is Pythagorean
if and only if the evaluation is equal to _tf, which in this example must be stored
as true in the row's value for _tf.
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 Matthew
West
Sent: Friday, May 01, 2015 1:37 PM
To: 'Thomas Johnston'; '[ontolog-forum] '
Subject: Re: [ontolog-forum] Watchout Watson: Here comes Amazon Machine
Learning - ZDNet- 2015.04.10
Dear Thomas,
Commercial databases have no explicit
ontology beyond the ontological commitments made in their database catalogs. I
try to articulate an implicit ontology which I believe they all share, in my
book that John alluded to.
The current SQL standard recognizes valid
time and transaction time, the former being the time in which the things and
objects the database is about exist, and the latter being the time in which
rows reflecting these things and changes are entered into the database and/or
marked as logically deleted.
[MW>]
Do you mean by “logically deleted” that the statement is no longer true but
once was, or that they were never true (say the record was entered in error or
a change of understanding)?
I have proposed a third temporal
dimension -- that in which the statements made by rows in tables are asserted
to be true. For example, a logically deleted row remains in a database as one
which no longer represents the assertion of the statement it makes. And just as
we can utter/write statements (de-indexicalized declarative sentences) that,
starting at some point in time, we are no longer willing to assert represent
statements we believe are true, so too we can enter rows into database tables
that represent statements that we are not yet, at that time, willing to assert
represent true statements. The former rows are tagged with "speech
act" time periods (see below) that are entirely in the past, and the
latter with time periods that are entirely in the future. Again, this is not in
the current SQL standard, nor in the current comp sci literature.
Assertions (and their withdrawals) are
speech acts, and so in my book, I attempt to introduce this third temporal
dimension as that. So I distinguish (i) rows in tables as physical
inscriptions; (ii) statements made by those rows (semantics); (iii) speech acts
associated with those semantics such as assertions and withdrawals, also
assents, dissents, and the whole panoply of propositional attitudes
(pragmatics); and (iv) the propositions expressed by those statements (the Holy
Grail of why we manage data in the first place).
I think that all of these are managed
objects which can be represented as managed objects in relational databases.
The only managed objects in today's databases, on the other hand, are the
physical tables, rows and columns themselves. Constraints preserve an imperfect
mapping to an interpretation, and the understanding of that interpretation is a
matter that falls outside the scope of the management of data itself. Or, at
least, so I understand a basic assumption underlying the current state of
affairs -- an assumption I do not make myself.
A bit of a soapbox email here. Apologies,
if needed.
Dear Matthew,
Possibility and necessity affect the logic, not the ontology:
> Another problematic category is possibilia (things that might be,
> or possibly are in some parallel universe).
They can be treated in the same way as plans for the future.
For example, if you're designing an airplane or a bridge, it's
a possibility until it's actually built.
> The criteria for including possibilia (or not) is utility vs
> the baggage that comes with the extra commitment.
The categories of parts, part numbers, etc., might be empty
in actuality, but they are specified in the ontology by the
same methods before and after the things are built.
There are, of course, issues about storing information about the
future in the database -- orders for future delivery of things
that don't yet exist, reservations for hotels, travel, etc.
The orders and reservations exist in the present (or past),
but they refer to things and events in the future.
Tom Johnston wrote a book about time and temporal issues in
databases. Perhaps he might care to comment on this point.
Following is an article in which I discuss issues about
modality, possible worlds, and the laws that govern them:
http://www.jfsowa.com/pubs/worlds.pdf
Worlds, models, and descriptions
And by the way, possibilities are another area where a strictly
nominalist position (e.g., Quine's or Goodman's) gets into trouble.
Clarence Irving Lewis, who defined the first modern versions
of modal logic, had been the chair of the philosophy department
at Harvard while Quine was a student and later a professor.
But Quine was very strongly opposed to any version of modal
logic and any talk of possibilia. Hao Wang, who had earned
a PhD under Quine's supervision, was very critical of Quine's
attitude. He called it *logical negativism*. See
Wang, Hao (1986) Beyond Analytic Philosophy: Doing Justice
to What We Know, MIT Press, Cambridge, MA.
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