 
 
No, the argument says John has known Q, ie a codified version of the logia,
and not the original, assuming that there has been one. It has weaknesses,
of course, like that John might have known the original, yet rather referred
to Q in his text, or that the logia were given in a codified version in
the first place.
 
The argument alone does not allow a firm conclusion, but it fits well into
the dating usually given for the gospels.
 
 
 
Not necessarily, Luke may have trusted the version he knew better than the
version given by Matthew. Improving on Matthew would give a motive, for
instance.
 
As far as I know, the theory that Luke has known Matthew is based on a
statistical analysis of the texts.
 
 
 
Yep, but it will take another day or so to get the source. I hope your German
is good enough. :-)
 
 
 
I still do not see how copies from 200 allow to change the dating of John.
 
 
 
Yes, but an if gives only possibilities and no evidence. The authencity of
many letters is still discussed. It looks as if conclusions about them are not
drawn because some pet dogmas of the churches would probably fall with them as
well.
 
 
 
Well, rather like some newsletter of a political party reporting from the
big meeting. Not necessarily wrong, but certainly bad.
 
 
 
Yes, but the accuracy of their tradition is another problem.