John, (01)
An engineering model is in no way even remotely
similar to a possible world. A possible world is,
for the most part, a fantasy of what might
possibly happen, but can't be experienced in this
world, while a model (for us engineers) is an
abstraction of reality subject to validation. The
two are miles apart. A goal is also not a plan,
but every plan has a goal of one sort or another.
Without the plan, the goal is also a fantasy
without thought of realization. (02)
Neither a plan nor a model nor a goal need have
any relationship to the 4D or 3+1D representation;
plans for software applications, for example, have
no physical dimensionality in typical
applications. So goals often have to do with
achieving automated functionality, tested
validity, performance exceeding specifications,
and other metrics and -ilities. (03)
Planning is not necessarily followed by
scheduling, especially in cases where actual
schedules can only be guessed at, as in large
software development projects. A plan with
scheduling is more tightly bound, with variables
specified in terms of their interpretation
constants, than a plan that is more abstract -
typically one which is a "best practices" plan.
Best practices are often documented in plan form
with no hint of a schedule. A best practices plan
is very general, not a specific plan ready for
execution. (04)
It is true, however, that planning is ultimately
intended to be executed, sometimes in many
instances of the plan, as for best practice plans.
It is just not always interpreted by schedules,
though scheduling is often used in some
specialized classes of plans such as project
plans. (05)
A plan to put the red pyramid onto the green
block, for example, has only ordering constraints
imposed by the nature of gravity, blocks and
pyramids, not schedules, which have time bindings
and even mechanism and inventory bindings. (06)
I agree that Murphy's law is a hazard for plans,
and is usually the reason why plans begin as
abstract, unbound activities interconnected with
precedence diagrams such as IDEF0, but without
bindings to specific objects until each binding is
necessary to proceed with the plan's execution. (07)
The world is much larger than FOL and ontology can
possibly enfold. (08)
-Rich (09)
Sincerely,
Rich Cooper
EnglishLogicKernel.com
Rich AT EnglishLogicKernel DOT com
9 4 9 \ 5 2 5 - 5 7 1 2 (010)
-----Original Message-----
From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx
[mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On
Behalf Of John F. Sowa
Sent: Friday, August 05, 2011 7:59 AM
To: [ontolog-forum]
Subject: Re: [ontolog-forum] intangibles (was RE:
Why most classifications INare fuzzy) (011)
Dear Matthew, Avril, Doug, Rich, Leo, and Simon, (012)
I accidentally hit "send" before I finished. And
upon rereading
what I had written, I realize that Matthew had
written "modal realism"
but I had read it as "model realism". (013)
But that's a useful Freudian slip. If we could do
a global change
of "possible world" to "model", we would use a
term that is familiar
to engineers, and it would eliminate a huge amount
of metaphysical
confusion. (014)
In fact, Hintikka had used the term 'model set' to
specify what
Kripke called a possible world. Kripke made some
important
contributions beyond Hintikka. But if he had used
the term 'model'
instead of 'possible world', he would have saved a
lot of dead trees. (015)
JFS
>> I would really like to see a quotation from
some report at Shell
>> that supports the claim "just how I found the
word being used there". (016)
> MW: That is really quite insulting. (017)
I am very sorry. I did not consider that
suggestion insulting. I
would never trust my own memory about fine
distinctions between what
I and my colleagues had assumed. In fact, I
always quote people
verbatim when there is any possibility of
misinterpretation. (018)
> Attached is a diagram from training material
used to make sure the
> language was being used in the same way to
disambiguate terms like
> strategy, plan, mission, vision, objectives and
policy. (019)
At the level of detail in that diagram, there's
nothing I disagree with.
The term 'possible world' is the source of the
disagreement. (020)
JFS
>> When you get to the lowest level details,
>> there is almost no difference between an
imperative command (action
>> type) and a precondition-postcondition
declaration. You can have
>> a one-to-one correspondence. (021)
> MW: But they are not the same. (022)
True. But the one-to-one correspondence means
that you can replace
any action type with its pre and post conditions
(or vice-versa)
without making any difference in the sequence of
execution or the
results achieved. You can associate a time-stamp
with a condition
just as easily as an action type. (023)
Having that flexibility is valuable. Some kinds
of actions are much
easier to describe one way or the other. Tying
your shoe string is
much easier to specify by the conditions than by a
procedure. (024)
AS
> The necessarily inaccessible Lewis' modal
realist worlds are fine
> examples of something that the principle of
economical
> understandability PEU can clear-cut away,
without robbing anything
> away from the intellects. This is because one
can get by exactly as
> well or even better without them; if one can get
by as well without
> them, then they are not required, and what is
not required is an
> unwanted weight (025)
I agree. But sometimes it is useful to consider
the realization
of a specification. Calling it a model gives you
that option,
but it avoids the metaphysical baggage of possible
worlds. (026)
JFS
>>> But I disagree that "a plan is a set of
actions". Whether you're
>>> using a 4D analysis or 3+1D is irrelevant to
the definition of 'plan'. (027)
MW
>> Well I spent 30 years working for Shell, an
organization that lived
>> and thrived by creating plans and then
executing them.
>> My usage is just how I found the word being
used there. (028)
DF
> I would suggest that even at Shell, a plan is a
structured set of action
> templates, not a set of fully pre-described
actions. (029)
Yes. And for any physical actions, the instances
always contain
an immense amount of irrelevant detail that the
types omit. (030)
RC
> The idea of a plan drawing (a la architects) is
SO DIFFERENT in
> meaning as to be only lexically similar...
> There is no similarity in meaning, and no
commonality, between
> an engineering/architecture plan drawing and a
project plan... (031)
The drawings or other specification of the goal to
be achieved are
the single most essential part of a plan. Without
that, nothing
else matters. A *project plan*, as the adjective
shows, is a special
case of a plan that specifies a *project* for
achieving that goal. (032)
For an example where the overhead of a project
plan is not advisable,
see the comic book on "The Adventures of Task
Force Tim": (033)
http://www.jfsowa.com/computer/tftim.htm (034)
And please note that the goal is *not* identical
to the final result.
For any physical project, the goal always has far
less detail than
the result. It is a type, of which any instance
can be considered
a successful completion. (035)
Leo
> In the AI planning community, typically there
are 3 phases of "planning"
> 1) planning...
> 2) scheduling
> 3) execution. (036)
That's a good specialization of the meaning of
'plan'. But even in AI,
there are many variations. A robot, for example,
doesn't use a
project plan when it must respond within seconds. (037)
Leo
> You might look at Dan Nau's slides on automated
planning:
> http://www.cs.umd.edu/~nau/planning/slides/. His
first chapter
> takes you through multiple definitions of plan. (038)
Yes, and he does exactly what I recommended:
start with a survey
of definitions from a good dictionary. Then he
specialized some
senses for his examples. (039)
Furthermore, the AI work emphasizes the pre & post
conditions as
the means for deriving the specific action types. (040)
SES
> One thing covered in the book are some of the
work that is being
> done to deal with durations where the process
can't cleanly be
> separated into those the phases, as the outcome
of an action
> may be non-deterministic, etc. (041)
Yes. That's another reason why it's important to
be flexible
in the definition of 'plan'. Any plan that deals
with the real
world must always accommodate "Murphy's Law" --
something is
bound to go wrong and require an ad hoc fix. (042)
John (043)
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