I posted this message to LINGUIST:

Where can I find discussion of either of these questions?

[1]What are the rules that all languages which are used for communication by systems that are intelligent as humans has to obey?

[2] What are the rules that all languages which are used for communication by systems that are intelligent as humans, and have the known physiological and perceptual characteristics as hymans, has to obey?

It looks to me that at least [2] has to be a central question in psycholinguistics, because it tell which language universals are to be expected from the fact that languages are used for communication, and which are not and require other explanation. However, I failed to find any discussion of this.

The questions you ask are simply unanswerable.  There are no
general rules of the kind you mention that anyone knows of,
and so the question you ask cannot be answered.

Regards


                **************************************
Anthony Aristar                         Associate Professor
Moderator, LINGUIST
Linguistics Program                     Fax:   (409) 862 2292
Dept. of English                        Phone: (313) 741 1567
Texas A&M University
College Station, TX 77843-4227

URL: http://engserve.tamu.edu/pers/fac/aristar/

I was impressed. This guy apparently think that if we don't understand something, we can ignore it. So I send a one sentence reply, asking if he seriously thinks that this is a good reason not even to discuss the questions that I raised. Here is his reply:

Since you insist, I will be blunt.  LINGUIST list is a list 
for professional linguists. The question you wish to ask is
one which professional linguists would call "naive", by
which they mean simply a question which might be asked by 
an intelligent person who does not yet know enough linguistics.
Such a question is not one suitable for LINGUIST. If you really
wish to discuss it, you should direct it at a newsgroup such as 
sci.lang, where there are no such restrictions.

Regards 

Anthony Aristar
 

So, only "naive" people ask this kind of questions, but not professional linguists. Why not? Obviously, it is not because they already know the answers (see his first reply). Any other ideas?

While you think on it, here is my answer: they know intuitively that the answers to these questions will undermine their theories, and for them, their theories are more important than realy understanding the subject.