Recently Brian Greene did test Einstein zombie world again but in a
different way:

http://www.edge.org/3rd_culture/einstein07/einstein07_index.html
BRIAN GREENE: "When it comes to Albert Einstein, his contributions are
of such incredible magnitude that to get inside his head, and even for
a moment to get a feel for what it would be like to see the world with
such clarity and such insight, would be amazing. But if I was going to
ask him one question, I would probably stick to one a little bit more
down to earth, which is—he famously said that when it came to the
general theory of relativity, in some sense he wasn't waiting for the
data to show whether it was right or wrong; the theory was so
beautiful that it just had to be right. And when the data came in and
confirmed it, he claimed he wasn't even surprised, he in fact famously
said that had the data turned out differently, he would have been
sorry for the [dear lord?] because the theory was correct. That's how
much faith he had in theory. So the question I have is, we, many of
us, are working on Einstein's legacy in a sense, which is trying to
find the unified theory that he looked for such a long time and never
found, and we've been pursuing an approach called super string theory
for many years now. And it is a completely theoretical undertaking. It
is completely mathematical. It has yet to make contact with
experimental data. I would like to ask Einstein what he would think of
this approach to unification. Does he see the same kind of beauty, the
same kind of elegance, the same kind of powerful incisive ideas in
this framework to give him the confidence that he had in the general
theory of relativity? It would be great to have a response from him in
that regard, because we don't know when we're going to make contact
with experimental data. I think most of us in the field absolutely
will never have faith that this approach is right until we do make
contact with data, but it would be great to have the insight of the
master as to whether he feels that this smells right. That it is going
in the right direction. Many of us think that it is, but it would be
great to have his insight on that question as well."

So Brian Greene challenges Einstein zombie world: General relativity
is so beautiful that no experiment can refute it. How is that
possible?