Thomas, in response to your question about fluents:
A fluent is a pairing of (a Boolean function with all parameters
bound)
with (the value - T or F - which
the function has
to have to
"achieve" the fluent).
A set of fluents is essentially an FOL description of a
situation.
Instead of saying ~OnTop( A, B ), a fluent would be a row of
FOL, perhaps like this one:
< F, OnTop(A,B) >
which could be stored as the database entries:
< F, OnTop, A, B >
in traditional, not embedded function, relational databases.
But there is a wiki article on it that is likely to be more
informative than I am about it:
http://en.wikipedia.org/wiki/Fluent_(artificial_intelligence)
Fluents, in short, let you express FOL in database rows, but
require you to understand that notation more than the traditional FOL notation
does.
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: Thomas Johnston
[mailto:tmj44p@xxxxxxx]
Sent: Friday, May 01, 2015 4:29 PM
To: Rich Cooper; '[ontolog-forum] '
Subject: Re: [ontolog-forum] Watchout Watson: Here comes Amazon Machine
Learning - ZDNet- 2015.04.10
Rows in most implicitly
temporal (i.e. apparently non-temporal) relational tables represent contingent
states of affairs, e.g. that Customer 123 currently has name = "Smith"
and status = "Platinum".
Rows in unitemporal tables
include the open or closed time period during which C123 had that name and that
status.
Rows in bitemporal tables
include that first time period (valid time, called "state time" in my
recent book). But they also include a second time period, which represents the
time from when the row was physically created to when it was logically deleted
(i.e. marked deleted, but not physically deleted).
Rows in tritemporal tables --
discussed in my book but not in the current literature -- include a third time
period which represents when a person or group of persons (such as the
enterprise that owns the database in question) was, is or will be willing to
assert that the statement made by a row correctly describes a state of affairs,
i.e. is a true statement.
Updates to these tables
withdraw currently asserted rows with open time periods (most of them) because
an update makes such rows false. A current open time period row might say, for
example, that C123's status is Platinum from some past point in time into the
indefinite future. But with the update, we know that statement is false, and
that its open time period must be closed as of the time of the update.
Your description of fluents,
at first glance at least, seems to describes rows in tables which contain both
the data (C123 has name="Smith" and status="Platinum"), and
also a description of what the world must be like in order to make that
statement true. But since what the world must be like in order to make that
statement true is precisely that the designated customer has
name="Smith" and status="Platinum",. it doesn't seem that a
description of "what the world must be like in order to make (a) statement
true" adds any information to the original row.
Which suggests that I must
currently fail to understand what you mean by "fluents". Can you
enlighten me?
On Friday, May 1, 2015 5:09 PM,
Rich Cooper <metasemantics@xxxxxxxxxxxxxxxxxxxxxx> wrote:
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:
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.
Chief Technology Officer,
MetaSemantics Corporation
MetaSemantics AT
EnglishLogicKernel DOT com
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
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.
[MW>]
I’m still not clear (but interested).
This email originates
from Information Junction Ltd. Registered in England and Wales No. 6632177.
Registered office: 8
Ennismore Close, Letchworth Garden City, Hertfordshire, SG6 2SU.
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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