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From: jiml@alberta.UUCP
Newsgroups: sci.philosophy.tech
Subject: Re: Uncertainty in life
Message-ID: <1146@cavell.UUCP>
Date: Tue, 26-May-87 05:13:22 EDT
Article-I.D.: cavell.1146
Posted: Tue May 26 05:13:22 1987
Date-Received: Wed, 27-May-87 03:16:42 EDT
References: <6762@mimsy.UUCP> <1782@sphinx.uchicago.edu>
Reply-To: jiml@cavell.UUCP (Jim Laycock)
Organization: U. of Alberta, Edmonton, AB
Lines: 98
Keywords: Heisenberg certain

In article <1782@sphinx.uchicago.edu> ogil@sphinx.UUCP (Lord Julius) writes:
>In article <6762@mimsy.UUCP> pjn@brillig.UUCP (P. J. Narayanan) writes:
>>
>>I have this opinion about Heisenberg's uncertainty principle. 
>[Much deleted]
>>This suggests that you cannot know anything, repeat *ANYTHING*, for certain
>>in this world. It seems to me that this inference is too strong a one
>>philosophically, but really unavoidable from the equation.
>
>While it is true that Heisenberg's principle says we cannot know exactly
>the position or the momentum of any particle, applying it to the macro-
>scopic world in the form you propose makes little sense.  It all depends
>on what you mean by "certainty."
>
>There are things which I consider certain.  To take a silly example, 
>let's look at gravity.  I am certain that if I drop a stone it will fall
>to the ground.  Of course, that's trivial.  But I also know that, neglecting
>air resistance, it will fall with an acceleration of 9.8 meters per second
>squared.  This is not _exact_, but it is certain.  Within a very small       
>(microscopic) degree of error, I can tell you where the center of mass of
>that rock is going to be at any given point in time.  I can never tell
>exactly where it is or how fast it's moving, but that's OK.  I know
>enough for my peace of mind.
>[Much deleted]
>I am interested to see what some philosophers have to say out there.
>Any takers? (he says, climbing into his asbestos suit...) 

I'll bite, but first a bit of a disclaimer:  I'm a skeptic.  I'm not
sure how far to push the idea that "no knowledge is possible" (DesCartes'
cogito seems pretty reasonable, moreover for practical purposes I'm a
realist), but I'll take a stab at the above notion of certainty for
starters...

Epistemologists often define knowledge as "justified true belief".  One
can claim to know a proposition if one believes in it, is justified in
doing so, and if it also happens to be true.  Notwithstanding Gettier's
famous counter-example (which I can discuss upon request), I accept this
definition.  Note that it differs appreciably from the commonplace usage;
people often claim to have knowledge if they have a particularly powerful
belief, or have little cause to doubt the truth of a claim.
The problem is that no matter how strong one's conviction might be, and
no matter how justified one might be in holding some belief, there is
still a chance of error.  As long as that possibility exists, I frown
upon any attribution of 'certainty' as a relation between believer and
proposition.

Richard Dawkins, in his new book, _The Blind Watchmaker_ has a rather
vivid example concerning human certainty and statue-waving.
He recognizes that the macroscopic phenomena we observe
daily are subject to probabalistic events at the sub-atomic level.
All of our laws of classical physics are statistical generalizations of
quantum events.  As statistical epiphenomena, macroscopic occurrances
are relatively stable and predictable.  But it is conceivable that
gross disturbances might arise if sub-atomic events are "just right."
None of us have ever seen a statue wave at us.  I say this with all the
'certainty' I can muster, and I'm extremely justified in making the
claim, given that the probability that the molecules that make up the
arm of the statue might co-ordinate themselves in just the right fashion
so as to cause the arm to wave is infinitesimal.  Yet given enough time,
and enough statue-watchers, such an event will occur, whether the
observers are certain it will happen or not.

Of what value is 99.9999999999999999999999999% certainty/knowledge?
It is of immesurable worth, as far as leading our lives go.  The
decisions we make from minute to minute rely upon information that
is far less 'certain' than that.  But we shouldn't be using 'certain'
in a comparative sense as I did above, but I recognize that that is
how it is commonly conceived.  For a technical discussion, we need
absolute senses of 'certainty' and 'knowledge'.  Something is known
if and only if it is true.  The trouble is, the truth is INACCESSIBLE.

Before anyone jumps on me with the rebuttal, "well if you can't know
anything then how can you lead your life/do anything at all?", let
me emphasize that I have focused on the absolute notion of knowledge.
There are lots of claims and theories that I accept and believe, and
I'll argue 'til I'm blue in the face why a particular position is a
reasonable one to hold, or why it would be utterly foolish to hold a
contrary view, but I shy away from any talk about 'truth' in such
discussions.  So many people have claimed to have the truth.  They can't
all be right.

Oh, one last word: What do I think about the truth or the certainty of
statements in logic?  Do I hold that ~(p&~p)?  Well, I think to deny
the law of non-contradiction is an act of complete lunacy, but I have
yet to commit myself to the belief that such a statement is true.


  Jim Laycock
  ihnp4!alberta!cavell!jiml
    OR
  alberta!uqv-mts!Jim_Laycock
 
  Philosophy grad, University of Alberta (soon to be at Western Ontario)
 
  Interests:  Philosophies of Logic, Language, Mind, AI, and everything else.
  Summer Job:  Writing a parser to convert English sentences to sentences in
               predicate calculus (a la Montague, Gazdar).
               Supervisor:  Jeff Pelletier