I would argue that the context in which the question posed (is (instance)instanceOf(River)) would be crucial. True that a base definition could be made involving some sort of waterway with a current flow defined by gravitational forces (includes tidal plain). However....
- a boat captain navigating a way inland via a waterway would require his definition of river be modified to include being able to take his boat up it.
- a fisherman wishing to comply with legal statutes regarding wildlife harvesting might have to ascertain the exact point the river is designated a river in a fishing guide.
- a person attempting to use the water for drinking might be more concerned with the backflow or salinated ocean water into a tidal basin than the actual point of designation of a specific instance of a river.
- ...
This list could go on and on to infinity, thus supporting John’s argument in another thread that capturing all possible detail in a formally documented ontology is probably an impossible task.
Duane
On 16/02/09 9:24 AM, "FERENC KOVACS" <f.kovacs@xxxxxxxxxxxxxx> wrote:
Dear John,
Let us make a difference between the concept river and a particular river, such as the Colorado or any other.
The intension of the concept river will contain all the necessary properties that make up a river and that we are aware of. Mind you list may be open and endless…
So this is List 1
The extension of the concept river will list all the rivers that meet the properties either partly or fully, making sure that the one of the properties that makes a river a river and nothing else (the quality) is met.
That will give you List 2, in fact, the names of realia, a list of existing objects in reality. Tha is an inventory from the geographers, amp makers
Now at any point of time you can take an inventory of the objects existing either in your mind or in reality. Compare the experience and evidence and that of your knowledge (List 1 and List 2) to see if they are still relevant. It is not only the truth value that you are after, but a number of other aspects, such as check for correctness, timeliness, completeness, etc. as it is usual with the data/information processing business at large.
And whatever the answer you get, that has a time parameter as of that date the matter is as you have just found out.
You may notice that you do not need a separate definition here. But if you make one, of course that may change subject to the changes either in List 1 or in list 2.
But for continuously variable things like rivers, clouds, or
hurricanes, no notation of any kind can state precise criteria
for distinguishing borderline cases. When does a tropical
depression become a storm and then a hurricane? The weather
bureau states the criteria in terms of wind speed. But the
wind speeds vary enormously over the full extent, and they tend
to increase and decrease depending on conditions. The language
used to state those criteria is irrelevant.
You have made a point there. You are happy handling objects in space and invent various structures “to map” something devoid of time, yet we all know that timelessness is rubbish, just as freezing time, which is the end of story.
But we are not aware of time due to scientists who believe abstraction produces timeless concepts. No. they are wrong. Many concepts are in oblivion and most of them should end up in the bin as they are nothing new, just a new label, because people are fed up with the old terminology.
FK> We live in spacetime, and every existing thing (object of an
> ontology) is finally defined by its position in space and time.
> Those parameters are unique... Everything that exists has a
> date of birth and a date of death possible to forecast.
Since we were talking about rivers, how would you define the
birth and death of a river? Where is the source? Some previous
stream? Which of the many smaller streams that flow into it
qualifies as the source? What happens if any of those streams
dry up and begin flowing again in different seasons?
Every definition is a matter of agreement between the interested parties who have their own views and standpoints to be represented in the definition. Remember how any legal document is worded after the preamble… definitions… for the purpose of this agreement client means xyz, and that is the solution… agreement or harmonizing knowledge, which means that both parties check out their respective lists (1 and 2) and see if they match or not.
If any change in the usual behaviour of your favourite river is experienced, then you have new evidence and it is up to the community to decide to cal it a new name, move it to another class, or just accept that one or both lists are extended without label changing.
What happens to the Colorado River when the cities upstream
drain off so much water that the Colorado sometimes dries up
before it reaches the ocean? What happens to the mouth of
the river when it doesn't reach its mouth?
Then the Colorado river is dried up and ceases to be a river. River without water flowing in it is no longer a river, just a river basin.
What about the Ohio River, which is formed by the merger of the
Allegheny and the Monongahela Rivers at Pittsburgh? Precisely
which planes demarcate the boundaries between the source rivers
and the Ohio? How do you define those planes and river banks,
as the rivers rise and fall with different levels of rain?
Precisely which molecules of water are part of the river, part
of the wetlands nearby, or part of the evaporation above it?
Now when it comes to uncountables, you may recall that concepts are not just created/produced and identified as extensions and intensions, but as form and content.
All concept have a name, and that is their form. The content of a concept is what you have associated with it in your mind. To be able to speak the same language, we need to harmonize our thought/ideas and we use the two lists to check out any differences.
When a particular concept like water has in reality a form that has no clear boundaries in space, what you do is that you device a container which will be the form and the content will be the water in it. A form (concept) is always a property, or quality, i.e. a number (serial), and content is always an object, a quantity measured by tools derived from space and time parameters used at the end of the day for final identification.
FK> On the other hand concepts (man made artefacts) are also
> products, that is objects and they also follow the same rule.
Some artifacts fall into the same category as mathematical objects.
Please note the quotation by Kant:
"Thus only arbitrarily made concepts can be defined synthetically.
Such definitions... could also be called declarations, since in
them one declares one's thoughts or renders account of what one
understands by a word. This is the case with mathematicians."
An artifact invented by a particular person for a particular purpose
could be declared by that person as precisely as he or she desires.
On the other hand, many artifacts, such as a log cabin with a dirt
floor and actual living trees at its four corners, are composed of
natural objects that have so much variation that the boundaries
of the cabin are difficult to distinguish from its surroundings.
When was such a cabin born? When those four trees started to
sprout from acorns? When some person first laid another log
next to one of them? When enough logs were attached to form
four walls? When some person finally declared it to be finished?
What if it was never formally "finished", but the builder just
continued to extend it from a temporary shelter to a more
stable structure?
And when did the cabin die? When the builder left it? When
it started to lose parts? When most of the walls fell down?
When the four trees at the corners died? When all traces of
the parts vanished? But there are probably molecules from the
wood still in the ground. Do they have to vanish as well?
Suppose that somebody else built another log cabin next to
the first one, and other people eventually moved in to form
a village. When did the group of cabins or houses become a
village? When does a village become a town or a city? How
would you (or anyone else) define its date of birth?
Most of these issues are not issues in real life, as people introduce conventions and artificial measures. That is a pain in the ass, but reality. All that goes back to an even bigger scandal called causality. In a cause/effect model (actually it is equivalent with a teleological model in terms of describing physical phenomena and the end result of formalisations) you do not have clear cut boundaries just as in any event in time that you have been listing above. But measuring time is measuring movement or change and in many cases such changes will mark the boundaries.
Human life is subject to the availability of oxygen and water. Everybody dies if he/she does not get oxygen. And ask your doctor, what the final cause of any form of death is. It is the lack of oxygen in the brain, regardless of what has led the poor fellow into that condition.
FK> Why is this difficult to grasp?
What idea are you trying to express? That everything has
a precise birth & death? Those seem to be inherently vague
ideas. Even professional physicians and theologians cannot
agree on the exact time points for the beginning and ending
of human life. For nonliving things, those points seem to
be vague metaphors at best.
Well, whatever appears in space-time exists, when it disappears it cease to exist. In a natural language when and where often used interchangeably.
I will have to come back to this point later, now I must log off..
I'm definitely in favor of using logic for many purposes.
But note that stating the criteria in any version of logic
(even fuzzy logic) would do *nothing* to help us resolve
any of these questions.
John
Ferenc Kovacs
alias Frank
Genezistan
"Starting all over"
+44 7770654068 (Vodafone)
www.firkasz.com <http://www.firkasz.com/> and http://translationjournal.net/journal/46meaning.htm http://www.facebook.com/album.php?aid=2003546&l=1e704&id=1107563373
5 St. Mary's Place
Newbury, Berkshire
RG14 1EG
U.K.
From: John F. Sowa <sowa@xxxxxxxxxxx>
To: [ontolog-forum] <ontolog-forum@xxxxxxxxxxxxxxxx>
Sent: Monday, 16 February, 2009 7:19:26 AM
Subject: Re: [ontolog-forum] a skill of definition - "river"
Ali, Mitch, and Frank,
AH> If you've given a definition of River, and it is inadequate
> when you encounter something as the Okavango River, ought it
> not indicate that you only need to update your definition of
> river? Isn't the whole point of defining something trying to
> abstract the generalizable qualities / properties of the
> object/entity under consideration? You can still have a
> monotonic logic, you just need smart revision policies...
It's always possible to legislate a definition and to revise
the definition whenever you encounter an exception. But the
point of Waismann's notion of 'open texture' is that there is
no stopping point. If you arbitrarily choose a stopping point,
you will inevitably exclude unanticipated cases that are just
as reasonable as the ones you do include.
That is a serious problem for any legal system. Any system
of laws has inevitable exceptions and borderline cases that
require a judge and jury to decide.
MH> To address your Kant quote, natural language has a tendency
> to be imprecise and formal language tends towards precision,
> there is the relevance.
Kant's point, Wittgenstein's point, or Waismann's point hold
equally well for a well-written definition in a natural language
or in any version of symbolic logic. We all learned algebra
and geometry from books and teachers that used natural languages.
In fact, we learned logic and programming languages from books
and teachers that used NLs. But we were learning very precisely
defined mathematical concepts, and NLs are quite adequate for
teaching and expressing mathematical concepts precisely.
But for continuously variable things like rivers, clouds, or
hurricanes, no notation of any kind can state precise criteria
for distinguishing borderline cases. When does a tropical
depression become a storm and then a hurricane? The weather
bureau states the criteria in terms of wind speed. But the
wind speeds vary enormously over the full extent, and they tend
to increase and decrease depending on conditions. The language
used to state those criteria is irrelevant.
FK> We live in spacetime, and every existing thing (object of an
> ontology) is finally defined by its position in space and time.
> Those parameters are unique... Everything that exists has a
> date of birth and a date of death possible to forecast.
Since we were talking about rivers, how would you define the
birth and death of a river? Where is the source? Some previous
stream? Which of the many smaller streams that flow into it
qualifies as the source? What happens if any of those streams
dry up and begin flowing again in different seasons?
What happens to the Colorado River when the cities upstream
drain off so much water that the Colorado sometimes dries up
before it reaches the ocean? What happens to the mouth of
the river when it doesn't reach its mouth?
What about the Ohio River, which is formed by the merger of the
Allegheny and the Monongahela Rivers at Pittsburgh? Precisely
which planes demarcate the boundaries between the source rivers
and the Ohio? How do you define those planes and river banks,
as the rivers rise and fall with different levels of rain?
Precisely which molecules of water are part of the river, part
of the wetlands nearby, or part of the evaporation above it?
FK> On the other hand concepts (man made artefacts) are also
> products, that is objects and they also follow the same rule.
Some artifacts fall into the same category as mathematical objects.
Please note the quotation by Kant:
"Thus only arbitrarily made concepts can be defined synthetically.
Such definitions... could also be called declarations, since in
them one declares one's thoughts or renders account of what one
understands by a word. This is the case with mathematicians."
An artifact invented by a particular person for a particular purpose
could be declared by that person as precisely as he or she desires.
On the other hand, many artifacts, such as a log cabin with a dirt
floor and actual living trees at its four corners, are composed of
natural objects that have so much variation that the boundaries
of the cabin are difficult to distinguish from its surroundings.
When was such a cabin born? When those four trees started to
sprout from acorns? When some person first laid another log
next to one of them? When enough logs were attached to form
four walls? When some person finally declared it to be finished?
What if it was never formally "finished", but the builder just
continued to extend it from a temporary shelter to a more
stable structure?
And when did the cabin die? When the builder left it? When
it started to lose parts? When most of the walls fell down?
When the four trees at the corners died? When all traces of
the parts vanished? But there are probably molecules from the
wood still in the ground. Do they have to vanish as well?
Suppose that somebody else built another log cabin next to
the first one, and other people eventually moved in to form
a village. When did the group of cabins or houses become a
village? When does a village become a town or a city? How
would you (or anyone else) define its date of birth?
FK> Why is this difficult to grasp?
What idea are you trying to express? That everything has
a precise birth & death? Those seem to be inherently vague
ideas. Even professional physicians and theologians cannot
agree on the exact time points for the beginning and ending
of human life. For nonliving things, those points seem to
be vague metaphors at best.
I'm definitely in favor of using logic for many purposes.
But note that stating the criteria in any version of logic
(even fuzzy logic) would do *nothing* to help us resolve
any of these questions.
John
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