Nick,  It's fantastic how you punch right through the rhetoric to the deeper 
philosophical points.  Thanks.

It all depends on how you define "compute".  I think the best definition 
offered here (by Lee) is Soare's:

"A computation is a process whereby we proceed from initially given objects, 
called inputs, according to a fixed set of rules, called a program, procedure, 
or algorithm, through a series of steps and arrive at the end of these steps 
with a final result, called the output. The algorithm, as a set of rules 
proceeding from inputs to output, must be precise and definite, with each 
successive step clearly determined. (Soare, 1996, p. 286; definitional emphases 
in the original)"

The tricky part, in my opinion, is the "definite" requirement.  Definiteness 
seems like a relatively simple concept.  But it's not.  cf eg:

https://aphilosopherstake.com/2016/06/11/is-the-universe-part-of-the-world/

"We often speak as if we can quantify over absolutely everything, or at least 
absolutely every-actual-thing, but then continue to reason as if all of those 
(actual) things form a set. In many cases this looks perfectly harmless. If 
we’re talking about medium-sized dry goods, for example, we can think of our 
quantifiers as being implicitly restricted to e.g. physical objects (our 
second-order quantifiers to sets of those, etc). As on even the most liberal 
views of what counts as a physical object, there aren’t more than 
continuum-many (the cardinality of the real numbers) of them, we shouldn’t run 
into an immediate problems."

On 07/05/2016 09:43 PM, Nick Thompson wrote:
> Thanks, Frank. 
> Now all is clear.
> 
> On 07/05/2016 07:31 PM, Frank Wimberly wrote:
>> You can decide what it means to compute the square root of 2.  For example, 
>> you can program the Turing machine to enter an accept state if it finds a 
>> number (it can) whose square is within 10^-9 of 2.
>>
>> On 07/05/2016 06:25 PM, Nick Thompson wrote:> Thanks, Eric,
>>> 
>>>  Can one “compute” the square root of two? 


-- 
glen ep ropella ⊥ 971-280-5699

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