[Haskell-cafe] Re: Re: Re[2]: Wikipedia on first-class object

Ben Franksen ben.franksen at online.de
Sat Dec 29 11:14:47 EST 2007

Jonathan Cast wrote:
> On 28 Dec 2007, at 3:13 PM, Ben Franksen wrote:
>> Bulat Ziganshin wrote:
>>> Hello Yitzchak,
>>> Thursday, December 27, 2007, 12:10:21 PM, you wrote:
>>>> In particular,
>>>> two functions are equal only if they produce
>>>> the same value for every input, and in general it is
>>>> impossible for a computer to check that.
>>> "for a computer" is superfluous here. people are not smarter than
>>> computers and can't do anything that's impossible for computers
>> I don't think my computer can be sorry, but I know I can be.
>> And don't forget that there are 'undecidable' problems.
> Which I have never yet seen decided by a person...

In many cases, equality of functions has been decided by humans, as has
termination of programs. Of course this doesn't prove that humans can, in
principle, decide equality for any pair of functions. But neither has the
opposite been proved.


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