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From: ogil@sphinx.uchicago.edu (Lord Julius)
Newsgroups: sci.philosophy.tech
Subject: Re: Uncertainty in life
Message-ID: <1782@sphinx.uchicago.edu>
Date: Fri, 22-May-87 01:57:39 EDT
Article-I.D.: sphinx.1782
Posted: Fri May 22 01:57:39 1987
Date-Received: Sat, 23-May-87 14:31:16 EDT
References: <6762@mimsy.UUCP>
Reply-To: ogil@sphinx.UUCP (Lord Julius)
Organization: University of Chicago, Dept. of Physics
Lines: 63
Keywords: Heisenberg certain
Summary: Nonsense

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. It also makes one 
>think sbout the various notions men have about knowing things for certain
>and the practice of taking oath and testifying in a court of law etc.
>
[Deleted]
>
>P J Narayanan
>-------------

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.

In a recent _Fantasy and Science Fiction_ column, Isaac Asimov wrote
that he is glad to be living in an age where the basic laws of nature
are known.  I don't completely agree with that, but his justification
is decent.  He said that we know the rules of the universe very well on
a macroscopic scale, and that is the scale we have to deal with.  We even
know what's going on on the atomic level, and we have a good idea about
the nuclear level.  The business of science is to refine our knowledge.
Of course, major new ideas will result from this refinement, but they're
not likely to change the macroscopic application of the laws we know now.

With regard to moral certainty, we are entering an entirely different
ballpark.  Unless you believe humans are automatons whose every motion
is decided by the particles in our body, you cannot apply Heisenberg's
principle.  I'm not qualified to discuss moral certainty with any regard
to its history, but I do believe it cannot be equated with physical 
certainty.

Certainty in courtroom testimony, regardless of its philosophical
problems, seems to be unattainable in most cases, thanks to the 
fallibility of human memory.  Studies show that less than one half
(I can't recall exact percentages) of eyewitnesses disagree on the details
of observed mock crimes.  Perhaps we need a Heisenberg principle for
memory: (uncertainty in detail) * (uncertainty in time & location) > n,
where n is any natural number you care to choose (:-).

I am interested to see what some philosophers have to say out there.
Any takers? (he says, climbing into his asbestos suit...) 

-- 
Brian W. Ogilvie               	   |			"Tenants of the house,
...{uwvax,hao}!oddjob!sphinx!ogil  |  Thoughts of a dry brain in a dry season."