On Mon, 3 Nov 1997, Ranma Al'Thor wrote:

On Mon, 3 Nov 1997, Tempest- wrote:

	Heisenberg Uncertainty Principle (to the best of my knowledge) states that
you cannot observe any event or state without altering it yourself.  This
is the reason why you can't have ghosts walking around that can see us but
we can't see them, this princeable says that if they can see us, we MUST be
able to see them.

The Heisenberg Uncertainty Principle applies at the Quantum level, not the
higher level at which we might observe a ghost.

If anyone really cares, the Heisenberg Uncertainty Principle is really
a manifestation of a mathematical principle.  Namely, that two observables
whose operators do not commute can not be simultaneously observed with
arbitrary position.  Take position and momentum for instance.  If you
observe position then momentum, then in an identical system, momentum
first then position, you will get different results.  The first
observation in effect alters the system.  On the macroscopic scale
of things, the heisenberg principle is irrelevant however.