Darren New schrieb:

>> As mentioned before, in that sense there is /only/ programming through 
>> re-wiring, and therefore in that sense it doesn't make sense to even 
>> /mention/ such a property for any computing device.
> 
> But the whole magic of the property is that you *can* build such an 
> interpreter. Before the UTM was invented, it wasn't anyways clear to 
> anyone that such a thing was possible. Nobody knew that the rules of 
> arithmetic were adequate to express the rules of arithmetic.

True. Yet in 2009, people are taking it for granted by now, so if a 
contemporary Wikipedia article claims that Colossus could be 
re-programmed "partially (by re-wiring)", then I find it difficult to 
imagine that this is to be interpreted anything other than as "partially 
(by re-wiring /only/, providing no other option)".

/That/ was the initial starting point of the discussion we're now having.

So in this sense, say: Can a computing machine that is programmable /by 
re-wiring only/ ever be Turing complete?

I categorically say no, as there is obviously no way to feed such a 
machine with data isomorphic to some generic initial tape content for a 
UTM, and have it generate output data isomorphic to what the UTM would 
produce.

Unless, of course, you'd consider human "re-wiring operators" as being 
part of the machine, and their orders as being part of the input data, 
but I guess we agree that this is not normally the scope of how we'd 
define a computing device.

Post a reply to this message