Three Roads To Quantum Gravity

HOW TO COUNT SPACE
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A few months later I realized that the paper was basically
wrong. It was a brave attempt, but fatally ¯awed. Still, it got
me a few invitations to conferences. I don't think Stephen
Hawking was very happy when I used the occasion of his
invitation to give a talk at a conference he organized to
explain why making a lattice theory of gravity was not a very
smart thing to do. Some people seemed to like the idea, but I
did not see what else I could do ± it was a bad idea, and I had
the responsibility to explain why.
At another conference I left a copy of the paper in the
mailbox of someone called Ashok Das, who had told me he
was interested in doing something similar. Bryce DeWitt, who
is justly thought of as the father of serious research in
quantum gravity, looked for his mail in the same box and
assumed that my paper was intended for him. I'm sure he saw
all its shortcomings, but he was still kind enough to ask me to
join him as a postdoc. I owe my career to Bryce's mistake. At
that time I was being told that I had committed professional
suicide by working on quantum gravity and that I was
unlikely to get any job at all.
What was wrong with my ®rst paper was that Wilson's
lattice was an absolute, ®xed structure and thus clashed with
the relational nature of Einstein's theory of gravity. So my
theory did not contain gravity and had nothing at all to do
with relativity. To ®x this, the lattice itself would have to
become a dynamical structure which could evolve in time.
The key lesson I learned from this failed attempt was that one
cannot fashion a successful quantum theory of gravity out of
objects moving against a ®xed background.
At about this time I met Julian Barbour, a physicist and
philosopher who lives in a little village near Oxford. Julian
had left the academic world after his Ph.D. in order to have
the freedom to think deeply about the nature of space and
time. He supported himself by translating Russian scienti®c
journals into English and, away from the usual pressures of
academic life, he used his considerable linguistic skills to
read deeply into the history of our understanding of space and
time. He had understood from his study the importance of
the idea that space and time are relational, and he had then