OK, you don’t think that the kinds of brain inferences
I describe above should be called “inferences”. Fine. Let us
disagree as to that term, and then you can forget the comparison of the
inferencing speed of a brain and a computer – which is very peripheral to
the topic of the discussion.
>> It¹s needed for math, and in that context,
describing visualizable two or three-dimensional spaces,
>> is probably uncontroversial. When used by
analogy to refer to other concepts, I am not surprised that
>> terminology disputes can arise.
[PH] > We are talking past each other. Im not interested
in terminological disputes. Im talking about disagreements about the
logical/conceptual structure of rival ontologies.
Well, the way you described the dispute it sure sounded
like a terminological issue. One group wants to define “dimension”
in a way that excludes time, another group wants to define it so as to include
time. These would be two different senses – a terminology dispute.
Perhaps there was more to it, but on the surface it sure looks like terminology
to me.
>> Those can be represented with logical
consistency by categorizing them as alternative theories (Newton, Einstein),
>> each useful in certain situations, neither
necessarily expressing the fundamental structure of (whatever).
[PH] > Thats a weak get-out if we are trying to find (or
claiming the existence of) a single common ontology. Its a bit like having a
dictionary with words from a whole lot of languages in it, and calling it the
new Esperanto.
[[[7]]] [PC] >. If a child learned language by itself,
why don¹t the feral children speak the native language of their area fluently?
[PH] > I meant, without adult intervention. If you
think this is nonsense, learn something about
> sociolinguistics and the distinction between pidgin
and creole languages.
> A new 'native' language can evolve in a single
generation: the kids really do invent it
> themselves from talking to one another. None of
their parents speak it.
I am aware of the spontaneous creation of language among
children under those circumstances, and of sign languages as well. But now you
seem to be contradicting yourself. If the kids manage to create a language
among themselves, how is that possible except by attaching words to common
objects and events that they observe – an idea that you dismissed
sarcastically?
No, I have great respect for intellectuals, even when
they are at their most irritating. I *have* noticed that some of them
like to argue – more than seems necessary. Not a novel observation.
From:
ontolog-forum-bounces@xxxxxxxxxxxxxxxx
[mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Pat Hayes
Sent: Friday, March 07, 2008 1:16 PM
To: Patrick Cassidy
Cc: [ontolog-forum]
Subject: Re: [ontolog-forum] Ontology similarity and accurate
communication
At 11:41 PM -0500 3/6/08, Patrick Cassidy wrote:
Pat Hayes responded to a post on this thread.
OK, let¹s try to clarify the points that PatH either
misunderstood or just disagrees with.
[[1]] First, ³definition²
[PC] > An issue that has occupied some of my
attention lately has been the
Ø question of what basic ontological
concepts are sufficient to support
Ø accurate communication. I frame
the issue as being analogous to the
Ø "defining vocabulary" used by some
dictionaries as a controlled vocabulary
Ø with which they define all of their words. For
the Longman's, it is around
Ø 2000 words. The analogous question is how many
fundamental ontological
Ø elements (types/classes, and relations/functions)
are needed to logically
Ø specify the meanings of all other terms used in a
reasonably complex domain
Ø (having perhaps 100,000+ terms), to some adequate
level of detail?
[PH] > >
> Define "define". If you mean logically
define, then the number of defining terms is going to be comparable to the
total number of terms. All 'natural kind'
> terms, for example, are definitionally primitive.
When I used ³define² in reference to dictionary
definitions, the meaning should be clear, and ample examples are available.
Of course: but we are (or were) talking about ontologies,
which are quite different from dictionaries. Ontologies are written in
formalisms which have precise semantics. Please tell us what you mean by
'definition' when you use it in THIS context.
For the ³Conceptual defining vocabulary² , the
foundation ontology nicknamed thus to emphasize its **analogy** to the
linguistic defining vocabulary used in dictionaries, I carefully used the term
³logically specify the meaning² because I am aware that using the term ³define²
in an ontology context sets off fire alarms among those who can only interpret
that word as meaning ³necessary and sufficient definition².
Despite your rhetorical use of "fire alarm", the
fact remains that N&S condition is what is called a 'definition' in logic.
If you mean something else, please tell us what you mean precisely enough that
we can evaluate what you are saying. After all, you are drawing some very
important and far-reaching consequences from this argument, so it is rather
important that we be able to evaluate it.
I suppose that calling it a ³Conceptual Defining
Vocabulary² may cause a reaction in those who are sensitive to the specialized
meaning of ³define² in logic, but I thought that the distinction was
clear. Nevertheless, I will continue to use ³conceptual defining
vocabulary² because I think it is a useful analogy, even though the ³meanings²
of the terms in the ontologies created using the foundation ontology will
rarely be specified as necessary and sufficient logical ³definitions².
Stop using scare quotes to mask your own expressive
inadequacies. If you cannot tell us what YOU mean by definitions, then your
entire argument is just hot air and should be ignored by any responsible
engineer.
To ³specify the meaning² of a subtype is to
assert the necessary conditions for membership
Thre is no such thing as THE necessary conditions. I presume
you mean "some necessary conditions". But this is a very weak
constraint indeed. Will ANY facts do?
, for example:
(1) Asserting it as a subtype
(2) Asserting some property or relation not held
by other subtypes this could be as simple as being a subtype of another type.
(3) If there are necessary properties or
relations not inherited from any of its parent types, they must also be
asserted, using terms already in the conceptual defining vocabulary (aka
foundation ontology)
(4) If a subtype is precisely the intersection
of two parent types, that would be a necessary and sufficient definition.
Of course, the parent types may be primitives.
(5) Occasionally, other means of specifying
necessary and sufficient conditions will be used.
There are several criteria which I use to decide
whether a newly created concept representation is or is not primitive. I
have mentioned those before, and won¹t reiterate here.
Pointer? As this notion is so important to your ideas, you
really do have a responsibility to set them out clearly so that they can be
applied to example cases by others.
[[2]] how much vocabulary do we have in common?
[pc] >> My own suspicion is that the similarity **in
the fundamental concepts**
>> has to be very close to 100%.
[PH]
Ø There is quite convincing evidence that this is NOT
the case. In particular, human beings seem to
Ø communicate adequately even while the terms
they use in the communication are based on
Ø different mental ontologies. This happens so
often that it seems to be the norm rather than
Ø the exception; it is part of what makes it so hard
for reasonable people to come to agreement
Ø on basic ontological questions (such as whether time
is a dimension or not).
This is precisely the point that I
dispute, that the communication is based on different ontologies.
Do you have any actual evidence to support your case?
This is worth some discussion. The
hypothesis I presented is that the part that **is understood** is based on *exactly*
the same ontology, and where the ontologies differ there is
misunderstanding. In fact, I can¹t imagine how it can logically be
otherwise.
Different different interpretation (at least
when the parts that are different are part of the interpretation
process). But, **please** note that I said that what is similar in people
are the **fundamental concepts** - among which are the naïve physics sort of
notions that a weighty object will fall if not supported, when near the earth¹s
surface.
BUt these are exactly the ones on which people apparently do
not have identical ontologies
The point is that there are lots of these, including how
people interact with each other, that we learn from experience as we grow up.
HOW? How is it possible for two children in kindergarten to
align their mental ontologies? The idea doesn't even make sense: it would
require them to be telepathic.
And when we put labels on those common experiences, we
have the most basic ontology, which is extended by analogy to less concrete
things.
Wow, you slur over an incredible amount of pyschological and
psycholinguistic work very casually there. Your sketch seems to be based on a
late-19th-century picture of language learning as sticking labels on bundles of
experiences. One thing we know about that idea is that it doesn't work.
The exact process by which the analogical extensions
are created is a fascinating subject of research, but for the moment I am only
concerned with the end result we all have a large (> 1000) body of
common concepts for which we have terms that can be understood precisely, when
uttered in a familiar context (don¹t get started on that conversational and
situational context, OK?). So it appears that you disagree. But on
what basis?
Several. First, its clearly impossible to achieve such
perfect alignment in practice, an argument based basically on Quine's arguments
about indeterminacy of translation. Second, and most important, extended
experience of getting groups of people to collaborate in constructing
ontologies of common sense shows that differences are revealed very early on.
My favorite example, which my friends will have heard more times than they wish
to, was a group at Cycorp writing down all the things they could see in the
office we were in, and disagreeing heatedly about whether or not a framed
picture on a wall was in the office or part of the office. Over
an hours intense discussion ensued. The upshot was a gradual dawning that the
two people involved had different concepts of room. Two intelligent,
native English speakers had grown to adulthood without every noticing that
other people had a different mental ontology of rooms.
Funny thing you should mention time and ³dimension²
because that is precisely one of the good illustrations of this point.
When I did an exercise, creating linguistic (dictionary-style) definitions of
500 words not in the Longman¹s defining vocabulary, the one word I decided that
I needed that was not itself in the original vocabulary was ³dimension².
They didn¹t need it to define (the way they do their definitions)
any of the 65,000 words in the dictionary. Also to the point, 5-year olds
who know thousands of words and a lot of naïve physics and naïve sociology will
typically not have a clue as to what a ³dimension² is. That is a
word we learn in school. At least in my case I am sure I didn¹t have a
need for it until I learned some geometry. Ergo, the reason that
your disputants couldn¹t agree on whether time is a ³dimension² is because
³dimension² is not one of the fundamental concepts that are lexicalized in the
basic vocabulary.
No, that wasn't the reason. In fact most of the discussion
is carried on without using that word: I phrased it that way for reasons of
brevity. The dispute is the classical debate about continuants vs. occurrents.
For many people (Barry Smith being a notable example) this distinction is so
evident and stark that they insist on wiring it into their temporal ontologies
at a very basic level, and argue that to not do so is to commit a philosophical
error. To many others (me, Matthew West and I am pleased to add, A.N.Whitehead)
it seems like at most a loose, sometimes useful distinction between things and
processes, but nothing fundamental and not a taxonomic distinction; and at
least, a distinction to ba actively ignored.
Note that this is not a terminological debate. Of course you
won't find terms of art like 'continuant' in Longman's vocabulary; its a
specialized term in philosophical ontology. Nevertheless, one finds this
ontological disagreement arising over and over again, surfacing in a variety of
forms as disagreements over whether objects can have temporal parts, or whether
it makes sense to last for a time with having a temporal extent, or whether
'things' are 3-d or 4-d, and so on. Nothing at all to do with Longman's.
It¹s not part of the linguistic defining vocabulary of
words we all agree on. It¹s needed for math, and in that context,
describing visualizable two or three-dimensional spaces, is probably
uncontroversial. When used by analogy to refer to other concepts, I am
not surprised that terminology disputes can arise.
We are talking past each other. Im not interested in
terminological disputes. Im talking about disagreements about the
logical/conceptual structure of rival ontologies.
Of course, words differ in their meaning depending on
context, and that will screw up any but the most carefully planned
experiments. People who have no clue as to what an ³ontology² is
communicate quite well. in discussing accuracy of linguistic
communication, we are talking about the implied ontologies people use in
communicating, not the logic-based systems that computational ontologists
create.
You are however assuming that these 'implied ontologies' are
themselves logic-based. (If you deny this, please explain what you mean by an
'inference' when talking of brains.)
So with respect to your fascinating comment:
>> the terms they use in the
communication are based on different mental ontologies.
Just which terms are based on ³different ontologies²??
How did the researchers extract these ³ontologies²?
I believe the exact technique is proprietary (Cyc made me
sign a NDA :-), but it involves a feedback process of close interviewing and
comparing the results with what formal reasoners extract from the assertions.
It is really just conventional 'knowledge extraction' but backed up with formal
reasoners rather than expert systems.
How did they distinguish different *ontologies*
from different interpretations of *word sense*?
The two topics are closely related, of course. The
ontologies typically have to represent much finer distinctions of meaning than are
exhibited in any dictionary. A well-known examples is Cyc's catalog of the
various sense of 'cover'. Also, the ontologies often require concepts that have
no corresponding word, and may indeed be quite hard to even express in English.
This is interesting. References??
If we can find the terms that differ, that could
provide us with clues as to what words are not in the common basic vocabulary.
[[3]] Relative speed of brain and computer
[PC] >> The reasoning is something like this:
if the
>> brain (or a simulation) does as much computation as one of our
laptops, then
>> it can run at least 1 million inferences per second.
[PH] > There is no evidence whatever that the brain is
capable of this. In fact, there near-conclusive evidence
> that the human brain is incapable of quite simple
logical inferences without external
> support (such as drawing a diagram or writing a
formula). In particular, people - even
> with logical training - consistently make
systematic errors when given
> simple modus tollens reasoning tasks, with confidences
in the 90% range.
First, note that I said
***if*** the brain does as much computation. It¹s true, I think it does
more, but of course not in a linear binary manner. Second, and more
importantly, I did *not* say that the brain does **conscious and
sequential** modus ponens inferencing of the type we do with our logic
formalisms. It does its inferencing by massively parallel signal
processing.
That is irrelevant. Logic isn't inherently conscious and
sequential. Large theorem proving engines also use massively parallel hardware.
We have, in fact, no real idea how the brain does inferences, or even if it
really does them at all in any meaningful sense. "Signal processing"
is just word-salad.
With >10**11 neurons, each with > 1000
connections to other neurons, firing at multiple times per second, it hardly
seems like a bold assertion to imagine that it will accomplish at least the FOL
equivalent of 1 million inferences per second.
I think it is pure, and really do mean pure, fantasy.
The visual system processes images
No, it doesn't. What leaves the retina up the optic nerve is
already no longer an image, and there aren't any images in the visual cortex.
(There are 'image maps', but that just means that the brain uses neural
proximity to encode local retinal proximity, which one might expect from a
neural architecture.)
multiple times per second to a level of detail that our
fastest computers cannot yet mimic. When a baseball batter sees a ball
coming at him for a few tenths of a second and starts swinging, just how
inference-equivalents do you think it would take to process the image,
calculate the proper swing, and send the signals to the proper muscles?
You are making an old fallacy here, that the human
perceptual/motor system processes information like a 1960s computer or a 1940s
gun-aiming system would. First, the batter isnt 'processing the image', he is
focussed sharply on a limited but highly informative set of cues in the stance
and motion of the pitcher and the ball. BTW, its interesting that fielders can
turn and run in the right direction and speed without seeing the strike at all:
you can black out their vision just before the bat hits the ball, and they
already know which way the ball is travelling and approximately how fast.
Second, neither the batter nor the fielder needs to compute the entire
trajectory of the ball: they just need to get it inside some broad parameters.
What needed is qualitative reasoning rather than detailed numerical simulation.
Less than 300,000? Then you should be able to write a
program to do that really easily, at 2 gigahertz.
With the right hardware support, Im sure I could. Robots
which play killer table-tennis have been built with such specialized vision
systems.
[[4]] How close are the ontologies of two different people
[PC] >> A similarity of 99.9% in two different
fundamental
>> ontologies may not be enough for any meaningful level of
communication.
[PH] > Look, this HAS to be nonsensical. If this really
were true, how could human
beings EVER succeed in communicating?
Because our basic ontologies are in fact closer
than that.
And how did they get that way? Its not in our DNA, for sure:
there isn't room.
[PH} > There is no way you and I could come to a
logically secure agreement
> on 1000 axioms even if we had months to do it in and
had nothing else to do.
> But children learn natural language at a rate of around
20 new words per day around
> the ages of 4-6 years old, pretty much all by
themselves.
Talk about nonsense. If a child learned
language by itself, why don¹t the feral children speak the native language of
their area fluently?
I meant, without adult intervention. If you think this is
nonsense, learn something about sociolinguistics and the distinction between
pidgin and creole languages. A new 'native' language can evolve in a single
generation: the kids really do invent it themselves from talking to one
another. None of their parents speak it.
Yes, children learn first largely by pointing to
instances, but when a young child visits a zoo and points to a tiger and says
³pussy cat² we know that her internal definition of Felidae has not yet reached
the level of detail of an adult. The internal meanings of words do get
refined as people have more experience of the world and learn more about the
language.
First, in talking about the shared
common ontology expressed in language, I am discussing the kind of basic
notions people use in general communication, and in particular when trying to
explain things clearly to one another.
These words are associated with their meanings by experience
in context, not by discussions among opinionated academics.
Your anti-intellectualism is almost palpable, but it stands
you in poor stead when taking part in such opinionated discussions (like this
one).
The intended meanings of the words people use when
they are trying to be clear are almost always understood properly
In a sense that may be true, but that sense does not
require them to be mapped into identical mental ontologies. I suspect this
is where you make your basic mistake, by assuming that it does.
because the words are chosen to minimize the potential for
misinterpretation the speaker knows how the listener will interpret those
words. The issue remains, when I ask you to explain the meaning of
something, how could I possibly understand the answer unless you used words
whose meanings we both agree on?
Again, in a sense this is true, but that sense of 'agree on
meaning' doesn't entail the impossibly high standard of possessing identical
ontologies. It only requires that we draw conclusions which we each express in
the same words. The guy who thought a room was a hollow space in an architects
specification and the woman who thought it was a decorated, inhabitable
interior space can get by almost all the time using the English word 'room' to
one another and each understanding it their own way and each drawing
conclusions that differ in unspoken ways that do not matter enough to clarify
under normal conditions. It is only when they need to agree the point where
they are willing to have their statements set in ontological stone, that the
divergences suddenly become apparent. And it is notable in both this and the
temporal/continuant case, that people find it extremely hard to 'think
the other way', to see the other 'point of view' (as we often say). It much
easier to attribute a disagreement over words to a casual factual disagreement
or a temporary idiosyncracy or some other harmless explanation, than it is to
delve into the real sources.
Yet that happens every day many times a day to almost
everyone. By age 5 or 6, children are capable of learning by being
told. They have a good part of the basic defining vocabulary by that
point. I suspect that the basic vocabulary isn¹t near its adult level until the
teens.
Can you and me agree on an ontology?
Well, you are, let us say, contentious, but I still believe that we could
come to agreement on a lot more than 1000 axioms, provide that both of us had
the time to discuss it and neither of us insists on throwing out something that
the other proposes on any grounds other than a logical inconsistency with other
parts of the ontology, or a fatal vagueness that makes it impossible to relate
one to the other.
This is a common belief. Get two reasonable people together
and choose a topic they both know something (but not too much) about, and they
will just come to agree on the facts, and then they can just write them down,
and voila, an ontology! This was what Doug Lenat had in mind when he began Cyc.
Guess what: it DOESNT WORK. They can agree on just about everything as two
people speaking English, and they STILL can disagree, and sharply so, when they
try to write down what they know in a precise formalism. It happens again and
again: anyone who has tried to do knowledge extraction, especially in a group
setting, knows this from their first experience. And its not because they are
having to wrestle with nasty gnarly logic notations: the same thing occurs when
people are constructing concept maps, for example, with the smoothest graphical
human-oriented GUIs that anyone can make. The point is that ordinary English
conversation never gets conceptually deep: it doesn't need to, and English (NL
in general) hasn't evolved to do conceptual analysis (which is probably why
philosophy is so wordy see http://web.maths.unsw.edu.au/~jim/stovehelp.html).
The biggest reason people disagree on ontologies (when they
take the time to actually argue the points, and ignoring the most common source
of disagreement different use of terms) are either due to some insistence on
only one means of expressing a concept, even though logically consistent
alternatives may be preferred by others
BUt why do you think that people do prefer one way rather
than another? And 'prefer' is hardly adequate to describe some of the strength
of the disagreements involved. Ive had NSF grant applications rejected by
reviewers because I was using a mistaken (in their opinion) ontological
framework. Words like 'incomprehensible', 'incoherent' and so on get used.
or simple personal preference. Many
differences revolve around different theories of certain physical objects or
processes. Those can be represented with logical consistency by
categorizing them as alternative theories (Newton, Einstein), each useful in
certain situations, neither necessarily expressing the fundamental structure of
(whatever).
Thats a weak get-out if we are trying to find (or claiming
the existence of) a single common ontology. Its a bit like having a dictionary
with words from a whole lot of languages in it, and calling it the new
Esperanto.
You yourself have expressed the opinion that the
differences among existing ontologies are smaller than they are generally
considered to be
Yes, but that position is itself rejected by many of the
protagonists. So for example, my upper ontology of spatiotemporal entities
would be inconsistent with DOLCE by being too permissive (it would allow the
categories of continuant and occurrent to overlap)
, and logical consistency can be demonstrated by bridging
axioms among different ways of expressing the same idea. If we allow
logically consistent ways to express the same concept, or include slight
variations on a concept, agreement will be much easier. In the SUMO
project, one of the problems was that Adam and Ian took a minimalist view of
the upper ontology. They wanted to include only one way of representing
things in the world. In part, they had to produce a deliverable in a
specified time frame, which forced them to avoid extended discussion. In
addition, their concern, as I interpreted it, was that any redundancy would
eventually result in an intractable complexity of reasoning.
If that is what they really thought, they should have talked
to Cycorp about it.
But that doesn¹t mean that what they had in the
ontology was in any sense *wrong*. In some cases, it just didn¹t
satisfy the *preferences* of others. If they had adopted the
tactic of putting in whatever anyone wanted, properly related to the other
parts, it may have had a wider acceptance.
How would it have retained consistency?
The lack of time and funding for wider participation
was, I believe, also a major problem.
Do an experiment. Go to the Longman
dictionary site:
http://www.ldoceonline.com/
. . . and look at some of the definitions that
they give for words you select. (Don¹t worry too much about whether the
definitions actually give a good mental picture of the meaning of the word in
all its nuance and detail - they are designed to be simple, for learners
of English as a second language). The question is, do you think that
there are ambiguities in the defining words that make you uncertain as to what
they intend by those definitions?
I know the answer without looking: Yes, of course there are
such ambiguities. Almost every word in English is multiply ambiguous. Tell me
what 'on' means.
If you find any case where you think that you don¹t
properly understand the meanings of the words they use, let us know which ones.
[[5]] how do native speakers learn to agree?
[[PC]] >> We all know that people differ
in assumptions and beliefs, and yet we do
manage to communicate reasonably well in most cases. How can that be?
[PH] > Because the assumptions and beliefs themselves are
irrelevant to the communication:
> all
that matters is that we come to agreement on the beliefs we EXPRESS to one
another.
(PC I thought that¹s what the next part of the
paragraph was saying)
[PC] >> Well, it happens probably because we **know**
that we have different
assumptions and beliefs, and when communicating, only assume that there is a
certain fundamental set of knowledge in common, and only
rely on that basic
set of common assumptions and beliefs to express the ideas we want to
communicate.
Look, actual 'inner ontology' beliefs - even if they exist -
are very hard to access. We don't say them to one another directly: we may not
be able to even articulate most of them. We use words, which have hugely
under-determined meanings and are used for all sorts of social purposes (I can't
find the reference now, but its been reliable estimated from continuous
recordings of individual's speech that over half of what we say to one another
is content-free, basically social grooming.) So we almost never know
what other people's beliefs really are, in fact. At best, we might know, or
guess reliably, that they are such as to produce certain linguistic behavior,
though even that is highly indeterminate (people, especially kids, tend not to
go around pointing at things and saying their names encouragingly).
[PH] No, that doesn't work. First, people don't know
this.
[PC] Oh, come on. We all learn at an early age that
people believe different religions, and even different politics.
We don't know that we have different notions of 'room' or 'in'
or inconsistent beliefs about what it means to sit still and do nothing. In
fact, I bet that you don't even believe this :-)
Everyone knows that many other people are not experts
in the field we are experts in. We encounter differences of opinion as
soon as we can talk. When a specialist tries to explain something to a
non-specialist, s/he doesn¹t usually use technical jargon (unless s/he is
oblivious to the fact that it is jargon). I don¹t understand this
objection. How would you succinctly describe the Gricean conversational
maxims?
Dictionaries and Grice are irrelevant here. We aren't
talking about WORDS, but about ONTOLOGIES. Its not the same game.
[PH] Second, how is agreement on this vital common 'core'
achieved?
[PC] By growing up in an environment where the basic words
are used consistently to refer to the same common experiences that every person
has, regardless of where we grow up.
BUt most of those words DONT refer to experiences; and we
DONT have sufficiently common experiences. I knew what a sandstorm was before
I'd ever seen a desert.
We don¹t get together around a table to agree on the
basic words. We absorb them by living in an environment where they are
used consistently in the same sense, in a particular situation. We need
to see them used in a common linguistic environment to begin to grasp the
meaning.
===========================================
To understand the points above, recall that I am talking
about the basic vocabulary shared by most native speakers of a language, not
the technical words that we learn on special topics even something so
fundamental-seeming as ³dimension² or ³identity² (also not in LDOCE defining
vocabulary). There are plenty of those common words, and plenty more of
the specialized ones that can be defined (dictionary definition) using the
common ones, though in some cases a picture makes understanding a lot
easier.
Im talking about this as well. Remember, I started this game
doing naive physics.
When building a foundation ontology to serve as a Conceptual
Defining Vocabulary, we will of course create abstractions that are not
lexicalized in the linguistic defining vocabulary, in order to analyze the more
common concepts into their more fundamental component parts.
Another early fallacy, by the way (the idea that concepts
are assemblages of 'parts').
This presents an opportunity/risk for different
ways of analyzing the structure of common basic concepts like ³event¹.
But when the most fundamental components of meaning are extracted and
represented, the different ways that ontologists may prefer to represent the
same thing can all be represented with the most basic concepts, and the
relation between those different ways of viewing the same thing can be
precisely specified. I am aware that merely saying this will not convince
anyone.
Its been done (Cyc) and the results can be examined.
Impressive as Cyc is, I don't think it is encouraging for your line of
argument.
It requires a project to actually test the
hypothesis. That was also a subject of a previous posting. I wish
that the IKRIS project had continued I think it would have produced some
important data related to this hypothesis.
PatC
Patrick Cassidy
MICRA, Inc.
908-561-3416
cell: 908-565-4053
cassidy@xxxxxxxxx
From: Pat Hayes [mailto:phayes@xxxxxxx]
Sent: Thursday, March 06, 2008 4:15 PM
To: [ontolog-forum]
Cc: edbark@xxxxxxxx; Patrick Cassidy
Subject: Re: [ontolog-forum] Ontology similarity and accurate
communication
At 8:00 AM -0500 3/6/08, Patrick Cassidy wrote:
In the discussion on "orthogonal", Ed Barkmeyer
pointed out:
> My position is that two agents don't need to have non-overlapping
> ontologies to be unable to communicate effectively. Their ontologies
> can have a 90% overlap, but if there is one critical idea that one has
> and the other does not understand, they can't do business.
>
Ed focused on the problem that arises when one 'critical idea' differs
between the ontologies (or assumptions) of two different communicating
agents. I suspect that the problem can also arise when even minor
differences are present in the interpretations of communicated information,
because the interpretation of many concepts involve a very large number of
implications and associated inferences.
This question appears to me to be one that is worthy of a separate
field
of investigation: precisely how different can ontologies be while sustaining
an adequate level of accuracy in interpreting communications that rely on
the ontologies?
My own suspicion is that the similarity **in the fundamental concepts**
has to be very close to 100%.
There is quite convincing evidence that this is NOT the
case. In particular, human beings seem to communicate adequately even while the
terms they use in the communication are based on different mental ontologies.
This happens so often that it seems to be the norm rather than the exception;
it is part of what makes it so hard for reasonable people to come to agreement
on basic ontological questions (such as whether time is a dimension or not).
The reasoning is something like this: if the
brain (or a simulation) does as much computation as one of our laptops, then
it can run at least 1 million inferences per second.
There is no evidence whatever that the brain is capable of
this. In fact, there near-conclusive evidence that the human brain is incapable
of quite simple logical inferences without external support (such as drawing a
diagram or writing a formula). In particular, people - even with logical
training - consistently make systematic errors when given simple modus tollens
reasoning tasks, with confidences in the 90% range.
If (crudely
calculating) the inferences supported by the differing ontologies differ by
1 in 1000 then two different ontologies will generate 1000 differing
inferences per second from the same information. How much difference can
be
tolerated before something goes badly wrong - perhaps a direct logical
contradiction? My guess is that each serious "fact" that we
rely on to
support our everyday activities is supported by at least 1000 assumptions,
and getting one in a thousand wrong would invalidate the meaning of these
facts, making normal actions, expecting predictable results, effectively
impossible at any level. A similarity of 99.9% in two different
fundamental
ontologies may not be enough for any meaningful level of communication.
Look, this HAS to be nonsensical. If this really were true,
how could human beings EVER succeed in communicating? There is no way you and I
could come to a logically secure agreement on 1000 axioms even if we had months
to do it in and had nothing else to do. But children learn natural language at
a rate of around 20 new words per day around the ages of 4-6 years old,
pretty much all by themselves.
But, as I said at the start, this is an issue that needs
investigation.
We all know that people differ in assumptions and beliefs, and yet
we do
manage to communicate reasonably well in most cases. How can that be?
Because the assumptions and beliefs themselves are
irrelevant to the communication: all that matters is that we come to agreement
on the beliefs we EXPRESS to one another.
Well, it happens probably because we **know** that we have
different
assumptions and beliefs, and when communicating, only assume that there is a
certain fundamental set of knowledge in common, and only
rely on that basic
set of common assumptions and beliefs to express the ideas we want to
communicate.
No, that doesn't work. First, people don't know this.
Second, how is agreement on this vital common 'core' achieved?
If we 'misunderestimate' what our fellow conversant
knows,
there can be and often is a miscommunication. The ability to communicate
effectively depends on the ability to guess correctly what facts,
assumptions, and beliefs are likely to be shared by those with whom we
communicate. Among specialists, of course, a lot more common technical
knowledge is assumed.
An issue that has occupied some of my attention lately has been
the
question of what basic ontological concepts are sufficient to support
accurate communication. I frame the issue as being analogous to the
"defining vocabulary" used by some dictionaries as a controlled
vocabulary
with which they define all of their words. For the Longman's, it is
around
2000 words. The analogous question is how many fundamental ontological
elements (types/classes, and relations/functions) are needed to logically
specify the meanings of all other terms used in a reasonably complex domain
(having perhaps 100,000+ terms), to some adequate level of detail?
Define "define". If you mean logically define,
then the number of defining terms is going to be comparable to the total number
of terms. All 'natural kind' terms, for example, are definitionally primitive.
Most ontology languages don't even support definitions. Why
are you so focused on definitions which usually don't, and often can't, exist?
And which if they did exist would be largely functionally irrelevant in any
case?
I don't
know, but I think that this is a question that is important enough to
warrant substantial effort. My guess is in the 6,000-10,000 concept
range,
and that many of those are fundamental enough to be common to many complex
domains.
Any other guesses?
See above. My guess is that most terms we use, both the
communicate with and to speak with, have no definitions and do not need them.
We eliminated definitions from KIF because they caused only harm and provided
no functionality.
Pat Hayes
Patrick Cassidy
MICRA, Inc.
908-561-3416
cell: 908-565-4053
cassidy@xxxxxxxxx
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