Why "flat is better than nested"?

[Robin Becker]

On 27/10/2010 10:13, Stefan Behnel wrote:
> Robin Becker, 25.10.2010 15:56:
>> "I know that that that that that boy said is wrong!".
>
> What's a "that boy"?
>
> Stefan
>
well they say nested is hard. How about this break down


I know that X that a boy said is wrong. (any boy)
I know that X that the boy said is wrong. (a single boy)
I know that X that that boy said is wrong. (a specific boy)

now what could we substitute for X? eg "a Y", "the Y" or "that Y". Now I wonder 
what Y could be eg "word" "utterance" "that".

Any way a "that boy" is a specific boy and a "that that" is a specific that etc 
etc mumble mumble
-dementedly yrs-
Robin Becker