On Jun 8, 2007, at 17:39 , Pat Hayes wrote:
An example is described here:
Hey, nice survey. Utterly wrong in its
conclusions, but nice :-). I'm happy to welcome
you to this debate which many of us have been
involved in for quite a long time. (see for
But you come to the wrong conclusion. These two
'irreconcilable' ontologies ARE reconcilable, if
one does things right. The basic error is to
assume that what a philosopher means by 'exists'
has to be rendered into the logical existential
quantifier. That is good form, perhaps good
doctrine, when the game is to use formal logic to
sharpen philosophical debate; but that is not (or
at any rate should not be) what we are trying to
do here. The only sensible engineering attitude
to take towards the logical existential
quantifier is that it means "is an entity which
can be referred to", i.e. an entity which is the
denotation of a logical term; which as long as we
are using a reasonably classical logic is
essentially vacuous, of course. In a pluralistic
ontological framework, this cannot usually be
interpreted as any philosopher's notion of
existence. Those notions have to be treated as
classes or properties. Yes, existence IS a
predicate, when there are many notions of
existence to be considered. It has to be in any
logic which is intended to support
interoperability. (See the regrettably brief
. Sorry, I know that to say this to a philosopher
is like farting in church.)
After thinking and arguing about endurance and
perdurance for longer than I care to remember, I
have come a rather mundane conclusion which can
be summed up as follows: the continuant/occurrent
distinction is basically a distinction between
*how we use names* when talking about
spatiotemporal entities. It should not be seen as
a fundamental ontological distinction: it is
merely a linguistic distinction between modes of
_expression_. Things we call continuants are things
for which we tend to use the same name at
different times, so it is natural to encode
changes to their properties by attaching the
temporal parameter to their properties and
relations rather than to them: we write things
(inside Fritz Bratwurst Morning)
but we don't tend to talk of Fritz having
temporal parts. Special terminologies are used to
distinguish these temporally-sensitive relations
and properties: "fluents", "roles".
Occurrents, on the other hand, are things that we
do tend to speak of as having temporal parts or
'episodes', so it is natural to formalize
temporally-relative talk of those entities by
attaching the temporal qualifier to the name
itself. If Fritz and the Bratwurst were
occurrents, we might write
(inside (episode Morning Fritz)(episode Morning Bratwurst))
If one puts all philosophical discussion aside
for a moment and asks for a purely formal,
syntactic, way of distinguishing these ways of
describing things, what it seems to amount to is
where to attach a temporal parameter to a
time-free assertion. One might pose it as a
is true during a time-interval
invent a systematic way of encoding that fact by
incorporating the temporal parameter into the
logical _expression_. There are basically three
places it can go: attached to the entire
_expression_ (the 'ist' version:
(ist Morning (that (inside Fritz Bratwurst)))
using the paraphernalia of context logic), or
attached to the relation symbol (the first
option) or attached to one or more of the
argument terms (the second option). These
correspond respectively to the
hybrid/context-logical, continuant and occurrent
So, can these co-exist? Yes, of course. One can
use both (in fact, all three) modes of _expression_
in a single ontology, and in a reasonably
expressive logic (like IKL) can even write axioms
which relate them systematically. One does need
to use some discipline, to keep things straight.
One has to use even more discipline to use them
both (or all) in ways that respect the
philosophical prejudices of all users. For
example, if someone insists, as you do, that it
is incoherent or irrational to talk of temporal
parts of a continuant, then one will probably
need some kind of mechanical check to ensure that
no entity is ever spoken of in both temporal
styles. Such code could be written, but I
personally see no practical use for it, and large
amounts of harm caused by insisting upon the
distinction it would be there to check.
The continuant/occurrent distinction seems to be
of no actual value in real ontology
engineering[1]: on the contrary, in fact, recent
discussions on this very list and on
what I have always found to be the case, that as
soon as one gets away from nice homely examples
like Fritz' bratwurst, the distinction becomes
more and more tenuous, intuitions regarding it
dissolve, and the insistence on its being a basic
distinction rapidly becomes more trouble than it
is worth, causing long and pointless debates and
tending, if anything, to produce new, artificial
barriers to interoperability rather than help
with our practical goal. The real world is full
of entities which are both 'continuant' and
'occurrent', both thing and process: ocean waves,
storms, weather fronts, the Olympic flame, a
cumulus cloud, the interior of a Bessemer
furnace, the Krebs cycle, a tomato ripening on a
sunny windowsill, a cell expanding because the
sodium pumps in its membrane are insufficient to
oppose the osmotic pressure. The list goes on and
on: and the Brentano/Chisholm doctrine of mutual
incompatibility forces one to make all these
pointless and harmful ontological distinctions
between things and their lifespans, distinctions
which arise solely from the artificiality of this
doctrine of ontological apartheid.
Ive never seen any convincing pragmatic or
engineering argument for insisting on this as a
rigid distinction. There are plenty of purely
philosophical arguments, but then there are also
plenty of purely philosophical arguments in the
other direction. As you know, there are almost no
uncontroversial, universally accepted positions
in philosophy. Academic philosophy has no "normal
science", does not come to widely accepted
conclusions, and does not progress by a kind of
accumulation of evidence, where the task of each
new theory or argument is to account for
everything that earlier theories have done, but
to do so better. Philosophy is an ongoing
argument, where professional competence is
demonstrated by the ability to find a new flaw in
someone else's argument (which itself might be
the finding of a flaw in someone else's argument,
and so on for many layers). This means that while
almost any nontrivial philosophical position can
be bolstered by a long list of impressive
references, it can also can be attacked by an
equally long list of authorities who have argued
the opposite. This is why I have often said that
while philosophy can be of use to ontological
engineering, the appropriate attitude to take
towards a philosopher should be rather like one
adopts to a pet dog: they need to be housebroken,
properly trained and fed well, but it is most
important not to let them feel that they have the
upper hand. (I personally find the
'intuition-pump' (in Dennett's phrase) that your
paper obliquely uses, which I tend to attribute
to Simon's definition of "continuant" as
something which, when present, is wholly present,
quite unpersuasive because it is circular. If I
have temporal parts, then I am NOT wholly present
now. So am I wholly present now? In a sense yes,
in another sense no. I can run my intuition
One pragmatic argument I have heard is that the
distinction provides a kind of conceptual
scaffolding, an ontological discipline which
helps users render their intuitions more clearly
by requiring them to think more clearly,
basically. While this general idea certainly has
some merit (as for example in the successful
"Ontoclean" notions) it seems to have no real
purchase when applied to the continuant/occurrent
distinction, since the only purpose of making
this distinction is to maintain the distinction
itself. If one simply denies it then nothing is
thereby lost: the only result is that
distinctions, equally artificial, which have been
produced by this splitting (such as the required
distinction between Fritz and Fritz's lifespan)
are themselves no longer needed. The resulting
wave of simplification and unification rolls
through the ontology like a kind of global
relaxation into a simpler, and yet ironically
more expressive, ontological framework. So the
'discipline' which this framework requires serves
only to maintain the framework itself: it is like
a parade-ground exercise of marching in step.
I don't mean to argue that the intuitive
categories of 'enduring thing' and 'event' are
vacuous or useless. To the extent that they fit
with ontological intuitions, and with linguistic
usage, they are useful and important. But one can
admit all that, and even include them as
categories in a formal framework, without
requiring that they constitute a rigid taxonomy,
so that every physical thing MUST be in exactly
one of the two categories and as a matter of
logical necessity CANNOT be in both. Things can
be in both, and there is no need to be concerned
about this or try to forbid it. One can be
noncommittal about the category. Sometimes it is
useful to speak of temporal parts of
continuant-like entities. I had red hair as a
child. Why should one not be able to render that
by speaking of the child-temporal-part of me, and
attributing the color 'red' to its hair? If that
treats me as a process, I am perfectly happy to
be regarded as a process when that is useful. For
some purposes, indeed, it is difficult to see me
any other way than as a process (as for example
when we learnt that I lose and gain cells at what
might otherwise be an alarming rate.) The logical
sky does not fall when a temporal parameter is
attached to a continuant-like name. It is
perfectly clear what it means, even to those who
feel that it ought to be meaningless. One can (in
CL) even state conditions which translate this
form of logical description to the more
(forall (r (x Continuant)(t TemporalInterval))(if (r (x t)) (r x t) ))
Perfectly consistent, with a clear meaning, and it works.
(BTW, I suspect that nothing in the case which
started this thread comes anywhere close to this
degree of complexity or intensity of
[1] PS. I know that your framework and Dolce both
use it, and are both used by real people in real
settings. But that in itself is not evidence that
a similar but simpler framework which does not
have this distinction in it might not be even
PPS. Although I am doing all this emailing on
borrowed time, this issue is important enough
that I will make the following challenge. If
anyone has two actual ontologies (of a reasonable
size, in a reasonable formalism) which satisfy
Waclaw's **criterion** below for the reasons
outlined by Barry and Pierre, then please send
them to me and I will undertake to produce a
single ontology, written in CL or at worst IKL,
which is consistent but into which they can both
be translated so as to preserve entailments. That
is, my ontology may (will :-) require one or both
of them to be rendered into a different form, but
that re-rendering will not break any inferences,
if used uniformly. I may need a week or two.
At 08:34 AM 6/8/2007, Waclaw Kusnierczyk wrote:
The discussion would certainly be made clearer if one could support the
claims with a simple example; e.g.,
**two ontologies that taken together
are inconsistent, which cannot be reduced to a single consistent
ontology, and which both are necessary to cover the needs for all
involved in modeling the domain.**
As in mathematics, illustrative examples help in understanding dry
theories. I sympathize
with Bill, and would like to see a
counterexample to what he says.
On Jun 8, 2007, at 01:42 , John F. Sowa wrote:
Those are two important points, but they don't exhaust all the
options. There are many
cases where the ontologies happen to have
some features that create inconsistencies, but with some revisions
those inconsistencies could be eliminated by redefining some of
the terms. There are
also many cases where the same thing is
viewed at different levels of granularity or from different
perspectives. Any
inconsistencies caused by such methods
could also be eliminated, in principle.
However, the job of eliminating every one of the inconsistencies
that could arise could take an enormous amount of effort. Instead
of striving for a global consistency of everything, it might be
better to adopt methods that don't require global consistency.
What I was more trying to get at was the notion of identity (or
perhaps unity) for "ontologies". In Sean's original note, he said
something like "a single ontology cannot be used". You just gave us
a recipe for how to make (IMO) a single ontology from Sean's
"inconsistent" pieces, via the use of reformulation of his
pieces to
make them consistent, or via use of some kind of paraconsistency.
That was what I was trying to get to in my original note loose
talk
of "one single ontology for X can't ..." is usually based on
equally
loose understanding of the terms "ontology" and
"can't". Sorry I
wasn't more explicit about this in my original note.
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