X-Message-Number: 11649
Date: Fri, 30 Apr 1999 15:11:55 -0400
From: Daniel Crevier <>
Subject: On consciousness in a simulated world
References: <>

How about the following thought experiment to cast another light on the
question? I adapt it freely from Hans Moravec's Mind Children, Harvard 
University Press, 1988, p. 109.

Step 1: You are interfacing with a virtual reality setup that lets you 
experience a simulated outdoors  environment. This is sometimes in the 
next century, so the quality is far and away better that what we get 
today. The clouds and grass are not 'really real', but there can be no 
doubt that you are conscious of them just as if they were.

Step 2 : Sometimes in the next century again, you are operated upon by a 
robot surgeon which analyses a small part of your brain (say a piece of 
your  auditory cortex), and constructs an electronic circuit with the 
same input-output properties.  He then installs the circuit in your 
brain in such a way that you can switch between it and the original 
tissue. In this way, you can verify the accuracy of the simulation, 
which is tuned until the circuit and the original tissue feel exactly 
the same to you. When this is achieved, the robot removes the original 
tissue and wires in the circuit  permanently. 

This procedure can be repeated on all parts of your brain, little bit by 
little bit, in such a way that at every step you are in a position to 
verify that you are still really you. At the end, all of your brain will 
have been replaced by circuitry, and you will have become a 'simulation' 
of yourself. Yet there can be no denying that you will still be 
conscious. If not, at what point in the substitution process did you 
lose this awareness? So if you go outdooors and look at the sky and 
clouds, you'll enjoy them just as before.

Step 3: Instead of going outdoors, interface with the VR setup. Since 
you are still yourself, there is no reason you shouldn't be conscious of 
this virtual grass and clouds. But you are now a simulated being 
interfacing with a simulated reality. 

Which goes to show, in my view, that there can be consciousness in a 
machine that does not interface with the real world.

Daniel Crevier

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