XPost: comp.theory, comp.ai.philosophy, comp.software-eng   
   From: flibble@reddwarf.jmc   
      
   On Thu, 15 Jul 2021 18:48:01 +0100   
   Mr Flibble  wrote:   
      
   > On Thu, 15 Jul 2021 12:42:22 -0500   
   > olcott  wrote:   
   >   
   > > On 7/15/2021 12:22 PM, Mr Flibble wrote:   
   > > > Hi!   
   > > >   
   > > >  From Wikipedia Halting Problem page:   
   > > >   
   > > > 	For any program f that might determine if programs halt, a   
   > > > 	"pathological" program g, called with some input, can pass   
   > > > its own source and its input to f and then specifically do the   
   > > > 	opposite of what f predicts g will do. No f can exist that   
   > > > 	handles this case.   
   > > >   
   > > > To me this looks like everyone is assuming that the halting   
   > > > problem is undecidable based on a misunderstanding of the   
   > > > contradiction crystallized by [Strachen 1965].   
   > > >   
   > > > Strachen isn't saying the halting problem is undecidable, he is   
   > > > saying that there is a contradiction that means that a decider can   
   > > > not be a part of or called by that which is being decided. This   
   > > > doesn't mean that the halting problem is not undecidable but it   
   > > > does mean that if that Wikipedia extract is the current state of   
   > > > the art then nobody has proven that the HP is undecidable, at   
   > > > least for non-"pathological" programs.   
   > > >   
   > > > Olcott is on to something. :)   
   > > >   
   > > > /Flibble   
   > > >   
   > >   
   > > I am really glad that you are back.   
   > > Strachen  saying that the halting problem is undecidable.   
   >   
   > No he isn't he is saying a decider cannot decide a program that is   
   > aware of the decider, i.e. is "pathological". So, given two things:   
   >   
   > (1) a decider that can decide non-pathological programs, and   
   > (2) a decider that can detect if a program is pathological (i.e. is   
   > aware of the decider),   
   >   
   > then:   
   >   
   > the halting problem becomes decidable.   
   >   
   > Unless I am missing something.   
      
   Of course for (2) to be feasible the decider would probably have to be   
   a black box .. but I am HP newbie so I am merely thinking out loud. :D   
      
   /Flibble   
      
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