bnevin@CCH.BBN.COM (Bruce E. Nevin) (06/10/88)
Date: Thu, 9 Jun 88 09:31 EDT
From: Bruce E. Nevin <bnevin@cch.bbn.com>
Subject: Consensus and Reality
To: ailist@ai.ai.mit.edu
cc: hayes.pa@xerox.com, jmc@sail.stanford.edu, bn@cch.bbn.com
In AIList Digest 7.24, Pat Hayes <hayes.pa@Xerox.COM> writes:
PH> A question: if one doubts the existence of the physical world in which
PH> we live, what gives one such confidence in the existence of the other
I can't speak for Simon Brooke, but personally I don't think anyone
seriously doubts the existence of the physical world in which we live.
Something is going on here. The question is, what.
One reason for our present difficulty in this forum reaching consensus
about what "Reality" is, is that we are using the term in two senses:
The anti-consensus view is that there is an absolute Reality and that is
what we relate to and interact with. The consensus view is that what we
"know" about whatever it is that is going on here is limited and constrained
in many ways, yet we relate to our categorizations of the world expressing
that "knowledge" as though they were in fact the Reality itself. When a
consensual realist expresses doubt about the existence of something
generally taken to be real, I believe it is doubt about the status of a
mental/social construct, rather than doubt about the very existence of
anything to which the construct might more or less correspond. From one
very valid perspective there is no CRT screen in front of you, only an
ensemble of molecules. Not a very useful perspective for present
purposes. The point is that neither perspective denies the reality of
that to which the other refers as real, and neither is itself that
reality.
What is being overlooked by those who react with such allergic violence
to the notion of consensual reality is that there is a good relationship
between the two senses or understandings of the word "real": namely,
precisely that which makes science an evolving thing. John McCarthy
<JMC@SAIL.Stanford.EDU> has expressed it very well:
JM> Indeed science is a social activity and all information comes in
JM> through the senses. A cautious view of what we can learn would like to
JM> keep science close to observation and would pay attention to the consensus
JM> aspects of what we believe. However, our world is not constructed in
JM> a way that co-operates with such desires. Its basic aspects are far
JM> from observation, the truth about it is often hard to formulate in
JM> our languages, and some aspects of the truth may even be impossible to
JM> formulate. The consensus is often muddled or wrong.
The control on consensus is that our agreements about what is going on
must be such that the world lets us get away with them. But given our
propensity for ignoring (that is, agreeing to ignore) what doesn't fit,
that gives us lots of wiggle room. Cross-cultural and psychological
data abound. For a current example in science, consider all the
phenomena that are now respectable science and that previously were
ignored because they could not be described with linear functions.
But nature too is evolving, quite plausibly in ways not limited to the
biological and human spheres. The universe appears to be less like a
deterministic machine than a creative, unpredictable enterprise. I am
thinking now of Ilya Prigogine's _Order Out of Chaos_. "We must give up
the myth of complete knowledge that has haunted Western science for
three centuries. Both in the hard sciences and the so-called soft
sciences, we have only a window knowledge of the world we want to
describe." The very laws of nature continue to reconfigure at higher
levels of complexity. "Nature has no bottom line." (Prigogine, as
quoted in Brain/Mind Bulletin 11.15, 9/8/86. I don't have the book at
hand.)
Now perhaps I am misconstruing McCarthy's words, since he starts out
saying:
JM> The trouble with a consensual or any other subjective concept of reality
JM> is that it is scientifically implausible.
Since everything else in that message is consistent with the view
presented here, I believe he is overlooking the relationship between the
two aspects of what is real: the absolute Ding an Sich, and those
agreements that we hold about reality so long as we can get away with
it. In this relationship, consensual reality is not scientifically
implausible; it is, at its most refined, science itself.
JM> It will be even worse if we try to program to regard reality as
JM> consensual, since such a view is worse than false; it's incoherent.
I suggest looking at the following for a system that by all accounts
works pretty well:
Pask, Gordon. 1986. Conversational Systems. A chapter in _Human
Productivity Enhancement_, vol. 1, ed. J. Zeidner. Praeger, NY.
For the coherent philosophy, a start and references may be found in
another chapter in the same book:
Gregory, Dik. 1986. Philosophy and Practice in Knowledge
Representation. (In book cited above).
Winograd & Flores _Understanding Computers and Cognition_ arrive at a
very similar understanding by a different route. (Pask by way of
McCulloch, von Foerster, and his own development of Conversation Theory;
Winograd & Flores by way of Maturana & Varela (students of McCulloch)
and hermeneutics.)
JM> To deal with this matter I advocate a new branch of philosophy I call
JM> metaepistemology. It studies abstractly the relation between the
JM> structure of a world and what an intelligent system within the world
JM> can learn about it. This will depend on how the system is connected
JM> to the rest of the world and what the system regards as meaningful
JM> propositions about the world and what it accepts as evidence for these
JM> propositions.
Sounds close to Pask's conversation theory. There is also a new field
being advocated by Paul McLean (brain researcher), called epistemics.
It is said to concern how we can know our "knowing organs," the brain
and mind. "While epistemology examines knowing from the outside in,
epistemics looks at it from the inside out." (William Gray, quoted in
Brain/Mind Bulletin 7.6 (3/8/82).
Bruce Nevin
bn@cch.bbn.com
<usual_disclaimer>hayes.pa@XEROX.COM (06/11/88)
Date: Thu, 9 Jun 88 19:14 EDT From: hayes.pa@Xerox.COM Subject: Re: Consensus and Reality In-reply-to: "Bruce E. Nevin" <bnevin@cch.bbn.com>'s message of Thu, 9 Jun 88 09:31:41 EDT Subject: Consensus and Reality To: bnevin@cch.bbn.com cc: ailist@ai.ai.mit.edu, hayes.pa@Xerox.COM, jmc@sail.stanford.edu, bn@cch.bbn.com I suspect we agree, but are using words differently. Let me try to state a few things I think and see if you agree with them. First, what we believe ( know ) about the world - or, indeed, about anything else - can only be believed by virtue of it being expressed in some sort of descriptive framework, what is often called a `language of thought': hence, we must apprehend the world in some categorical framework: we think of our desks as being DESKS. Second, the terms which comprise our conceptual framework are often derived from interactions with other people: many - arguably, all - indeed were learned from other people, or at any rate during experiences in which other people played a central part. ( I am being deliberately vague here because almost any position one can take on nature/nurture is violently controversial: all I want to say is that either view is acceptable. ) None of this is held as terribly controversial by anyone in AI or cognitive science, so it may be that by your lights we are all consensual realists. I suspect that the difference is that you think that when we talk of reality we mean something more: some `absolute Reality', whatever the hell that is. All I mean is the physical world in which we live, the one whose existence no-one, it seems, doubts. One of the useful talents which people have is the ability to bring several different categorical frameworks to bear on a single topic, to think of things in several different ways. My CRT screen can be thought of ( correctly ) as an ensemble of molecules. But here is where you make a mistake: because the ensemble view is available, it does not follow that the CRT view is wrong, or vice versa. You say: BN> From one very valid perspective there is no BN> CRT screen in front of you, only an ensemble of BN> molecules. No: indeed, there is a collection of molecules in front of me, but it would be simply wrong to say that that was ALL there was in front of me, and to deny that this collection didnt also comprise a CRT. That perspective isnt valid. Perhaps we still agree. Let me in turn agree with something else which you seem to think we realists differ from: neither of these frameworks IS the reality. Of course not: no description of something IS that thing. We dont mix up beliefs about a world with the world itself: what makes you think we do? But to say that a belief about ( say ) my CRT is true is not to say that the belief IS the CRT. I suspect, as I said in my earlier note, that you have a stronger notion of Truth and Reality than I think is useful, and you attribute deep significance to the fact that this notion - "absolute Reality" - is somehow forever ineffable. We can never know Reality ( in your sense ): true, but this could not possibly be otherwise, since to know IS to have a true belief, and a belief is a description, and a description is couched in a conceptual framework. And as Ayer says, it is perverse to attribute tragic significance to what could not possibly be otherwise. When your discussion moves on to the evolution of nature, citing Pask, Winograd and Flores and other wierdos, Im afraid we just have to agree to silently disagree. Pat