Re: terminal von Neumann

[Howard Pattee <***>]

John,
I don?t want to cause more grief, so except where you mention him I will leave Bob out of 
my response. I will try, nevertheless, to correct any assumptions contrary to what von 
Neumann said.

John K said:
This to me seems to explain the comment that VN confounded simulation with construction - 
it was not that VN didn't realize or discuss the same problem, it was that his proposed 
solution involved making a direct analogy between what could be done in the computer via 
calculations and what is happening in nature, and then speculating that the one could 
cause the other, or be realized by it.

HP: Von Neumann said that what could be done via calculation, that is, by formal rules 
?throws half the problem out the window, and it may be the more important half. One has 
resigned oneself not to explain how these parts are made up of real things . . .? 
Clearly, vonN knows that the cause of computation cannot realize or cause the 
construction of real parts. This is so obvious. How could one think otherwise?

Also, von Neumann said his model was not a ?direct analogy? with Turing machines that 
must be explicitly described in every detail. Von Neumann said: ?It is, of course, 
equally clear at which point the analogy ceases to be valid. The natural gene does 
probably not contain a complete description of the object whose construction its presence 
stimulates.?

Von Neumann never assumed that the program or the gene could do more that construct by 
instructing (stimulate) how the real material parts (assumed to pre-exist in a natural 
reservoir) are connected. How to choose the real non-computable parts was a separate 
problem he treated in detail.

John: RR said that [construction] cannot happen unless the "model" is a) itself part of a 
natural system, and b) non computable. Self-realization of a program that could write its 
own software and construct its own hardware would satisfy criterion (a), but he argued 
that on logical grounds it could
not do that and remain computable. That to me seems to be the debate.

HP: I see no significant difference to debate here.

Howard