Path: utzoo!utgpu!watmath!iuvax!ndcheg!uceng!dmocsny
From: dmocsny@uceng.UC.EDU (daniel mocsny)
Newsgroups: comp.ai
Subject: Re: Simulation verus reality
Summary: It's not nice to fool Mother Nature
Message-ID: <864@uceng.UC.EDU>
Date: 13 Apr 89 06:35:31 GMT
References: <827@htsa.uucp> <5227@cs.Buffalo.EDU>
Organization: Univ. of Cincinnati, College of Engg.
Lines: 51

In article <5227@cs.Buffalo.EDU>, rapaport@sunybcs.uucp (William J. Rapaport) writes:
> And I quote:
> 
> "It is often suggested that a simulation of a phenomenon is not an
> instance of the p[henomenon being simulated.  For example, simulated
> hurricanes are not real hurricanes.  After all, as people often point
> out, simulated hurricanes don't get you wet.

Why doesn't, or couldn't, a simulated hurricane get you wet? Because
we aren't so good at simulating things yet, or because that would
be "cheating?"

For us to detect the presence of a hurricane, we must absorb some sort
of sensory data (raindrops on skin, the view of the ground rushing by
as the gale carries us along, or perhaps we detect the hurricane
indirectly by reading reports from instruments). To detect the presence
of a _simulation_, we must also absorb some sort of sensory data. This
means that the simulating device must have some link with the physical
world for it to convey messages to our sensory organs. If a simulation
can't deliver some sort of sensory experience to an observer, then in
what sense does it exist? For a simulation to be a simulation, it must
first exist...one hand clapping, that sort of thing...

Thus any device that simulates things must have two essential parts:
the computing engine that performs what we ordinarily think of as a
simulation, and the I/O subsystem that pumps energy into the physical
world in a way that provides a convincing sensory experience to an
observer. The I/O subsystem can be as crude as a line printer that
hammers out line after line of numbers. It can be a high-fidelity
digital audio system that faithfully simulates the sounds of an
orchestra (...heard any CD's lately? Simulated hurricanes don't get
you wet yet, but simulated orchestras can move one to tears). It can
be the future successor to NASA's VIVED (VIrtual Visual Environment
Display) with stereoscopic LCD goggles and head-motion cancelling
panning, that delivers a convincing panoramic view of simulated
surroundings with depth cues. 

Someday it may be neural-interface implants that directly induce
signals on our sensory nerves indistinguishable from the "real" thing.
A really good simulation should saturate the observer's sensory
bandwidth, just like the "real" thing does. 

Certainly a hurricane simulator could include a fancy device to generate
raindrops and impart the correct velocity vectors to them. Spraying
water as an output is not different in principle from pounding ink
into a page--the simulating device has an expendable store of
material that it imparts energy to and exhausts over the course of
the simulation.

Dan Mocsny
dmocsny@uceng.uc.edu