From: cam@castle.ed.ac.uk (Chris Malcolm)
Newsgroups: comp.ai.philosophy
Subject: Re: Grounding
Date: 13 Oct 92 22:48:37 GMT
Organization: Edinburgh University

In article <718611244@sheol.UUCP> throopw@sheol.UUCP (Wayne Throop) writes:

>Now, with that said, I still don't see that the history of how that
>algorithm came to be, or even the details of how the process that
>realizes the algorithm was instantiated, have anything to do with
>whether the process itself "is grounded".

>For example, is an aircraft pilot who has trained in a simulator
>"grounded" in a real plane? I'd have to say yes (at least, in so far as
>the simulated experience matched real experience).  The pilot can fly
>the plane, and when the pilot says "look at the airspeed indicator", the
>"airspeed indicator" symbol used is grounded. 

So we agree that "grounded" is not just an immediately present and
always measurable property of a system, but is a capacity; and a
system can be considered to have that capacity, even if it can't
exercise it just now, but if it would be able to demonstrate it later,
when circumstances were appropriate.

A (mind in a) brain in a vat, which has always been in a vat, is
ungrounded. If my brain were removed and placed in a vat, it would
still be grounded, I would still be able to -- given approp
reconnections -- of doing appropriate things and talking sense. But
after years in the vat, I wouldn't be quite so grounded -- I would
have begun to lose touch with reality. And after some time I might
become quite mad, completely ungrounded, and ungroundable.

It would be possible for me to build a robot with fixed knowledge
about the world which was -- to begin with -- quite grounded: it would
behave appropriately, its internal symbols would properly refer, etc..
But because its knowledge can't change, yet the world does, and its
sensors and perceptions inevitably make mistakes sometimes, mismatches
between its beliefs and the world will gradually build up. It will
gradually lose touch with reality. It will gradually become less and
less grounded.

I don't like calling such a creature "grounded". I would rather say
that it is, by coincidence (an intended coincidence), capable of
pretending to be grounded for a while. In other words, I would prefer
not to call "grounded" anything which lacks the capacity to maintain
its state of groundedness.

That's where history comes in: things which are grounded in the sense
of being capable of maintaining a state of groundedness are creatures
designed to have histories. They don't need to have a history; but
they must be capable of having a history -- of development and
adaptation. It is probably the case that a creature capable of this kind of
self-calibrating grounding can far more easily become grounded by
mucking around in the world than by being fed a ready-grounded
database and inference engine. If that is the case, it is most likely
that anything we encounter which is grounded in my self-calibrating
sense will already have a history, since that would be the easiest way
for it to become as it is.

My contention is that restricting the concept of "grounded" to having
this kind of self-calibrating groundedness avoids a lot of the
paradoxes of a concept of "grounded" which is just a property of a
system, rather than a combination of property and capacity to maintain
the property.
-- 
Chris Malcolm    cam@uk.ac.ed.aifh          +44 (0)31 650 3085
Department of Artificial Intelligence,    Edinburgh University
5 Forrest Hill, Edinburgh, EH1 2QL, UK                DoD #205
Newsgroups: comp.ai.philosophy