Re: Proof by construction, again (was Re: [sl4] prove your source code)

From: Matt Mahoney (
Date: Sat Jul 19 2008 - 11:43:38 MDT

--- On Sat, 7/19/08, Tim Freeman <> wrote:

> Someone whose attribution was deleted allegedly said:
> > Actually, the difficulty I had in mind was the seeming
> impossibility of
> > *proving* one's source code to another.
> From: "Stuart Armstrong"
> <>
> Date: Wed, 16 Jul 2008 16:03:40 +0200
> >If one SI had the details of how the
> >other was historically constructed; if she has access to the full
> >memory of the other, the physical makeup, follows her subroutines, and
> >is convinced that the source code is robust against being overthrown
> >by a secret command of the type above, then trust may be possible.
> Entity A could prove to entity B that it has source code S by
> consenting to be replaced by a new entity A' that was constructed by a
> manufacturing process jointly monitored by A and B. During this
> process, both A and B observe that A' is constructed to run source
> code S. After A' is constructed, A shuts down and gives all of its
> resources to A'.

But A cannot know if S is its own source code. (I assume that S includes current state information needed to make a copy of itself). If it could know, then A could simulate itself (with infinite recursion, which is impossible).

-- Matt Mahoney,

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