The Quantum Structure of Space and Time

About one hundred years ago, at the invitation of Ernest Solvay, the leading
physicists of the time gathered in the hotel Mktropole for a 6-day mythical meeting.
This meeting began a tradition of unique conferences that shaped modern science.
A total of 22 conferences have taken place every three years except during war
periods, covering most aspects at the frontiers of physics.
This year’s meeting continues the tradition. It is a great honor for me and a
moving moment to welcome all of you to the 23rd Solvay Conference in Physics, in
the building where the first meeting took place.
A distinctive feature of the Solvay Conferences is that they benefit from the
support and encouragement of the Royal Family. The pictures of Einstein with the
Queen Elisabeth of Belgium are in the mind of all physicists. It is with a respectful
gratitude that we acknowledge the continuation of this tradition today, at the time
of the celebration of the 175th anniversary of Belgium.
At the start of the 23rd Solvay Conference, I would like to have a thought for
Ernest Solvay, the Founder of the Institutes, and for the men who assisted him in
this enterprise, Paul Hkger and Hendrik Lorentz.
Born in 1838, Ernest Solvay exhibited a passion for physics and chemistry from
a very young age. He developed a new process for industrial production of sodium
carbonate (NazCOs – “soude” in French, not soda^” (in the plural) as I could
see on some uncontrolled web side). This was at the origin of his wealth, which
he used to create many charitable foundations. In particular, after the success of
the 1911 Solvay Conference, he founded the International Institute of Physics. The
mission of the Institute was “to promote research, the purpose of which is to enlarge
and deepen our understanding of natural phenomena, without excluding problems
xiv The Quantum Structure of Space and Time
belonging to other areas of science provided that these are connected with physics”.
Mr. Solvay, we are very fortunate that the same interest in fundamental science
has been transmitted to the following generations.
Paul HBger and Hkndrik Lorentz played also a central role in the foundation of
the Institutes. H6ger was professor at the UniversitB Libre de Bruxelles and a close
collaborator of Ernest Solvay. He wrote in 1912 the rules of the Institute of Physics
with the Dutch theoretical physicist Hendrik Lorentz, 1902 Nobel Laureate. Lorentz
was the first scientific chair of the Institute until his death in 1928. He “governed”
(if I can say so) the Institute with an iron hand in a velvet glove. His exceptional
vision of physics and his diplomatic skills were the keys to the lasting scientific
success of the Solvay Institutes. *****
It is instructive to read the original rules of the Institutes that prevailed until
1949. They tell us a lot about the remarkable personalities and foresights of Ernest
Solvay and of Hendrik Lorentz. These rules are astonishingly modern and most of
them are still valid today.
Ernest Solvay and Hendrik Lorentz clearly saw, for instance that science is
international. There is no Dutch or French or German science. Science is universal
and an activity that elevates mankind without border. This absence of compromise
to nationalisms put the Solvay Institutes in a unique position after the First World
War and enabled them to play a leading role in the reconciliation of French and
German scientists.
One can also see some distrust of Lorentz to fashion or well-established schools.
There is an explicit paragraph in the rules that states that invitations to the Solvay
Conference should be made on the sole basis of scientific merit and originality,
irrespective of whether the scientists work in a well-established institution or in an
obscure place, and with no account taken of their official recognitions.
Another interesting rule – but this is more on the anecdotic side – is that Lorentz
designated himself, in 1912, scientific chair of the Institutes until 1930! If one recalls
that he died in 1928, this is really a life self-crowning that tells a lot about his strong
personality.
There are, however, two points on which we deviate from the original rules.
One is the limit on the number of invited participants to the Solvay Conferences.
Knowing the natural tendency of humanity to inflation, this number was fixed, by
rule, to be 25. And that rule was strictly adhered to until the last Solvay Conference
chaired by Lorentz, in 1927. We are today 60. Is this a signal of weakness on the
part of the organizers? I do not think so. It is just the sign that science and
the number of scientists have exploded in the 20th century. I was told that if one
counts the total number of physicists that ever did research since the beginning of
humanity, about 90 percents are living now. I therefore think that it is as difficult
today to pick 60 physicists as it was in the early days to pick 25.
Opening Session
Another striking paragraph in the text written in 1912 concerns the lifetime
of the Institutes, which was fixed to be 30 years. This rule reflects, I believe, the
optimism that prevailed at the time of the foundation of the Institute, that all
problems of physics would be solved after a finite amount of time.
We clearly deviate from this rule, and for good reasons. Science, like history,
is not finished. Today’s conference will not be a replay of the 1911 conference in
which we will reproduce, on the occasion of the international year of physics, the
discussions between Einstein, Lorentz and Marie Curie. No, we will be interested
in new questions, in new challenges, in new physics. These new questions can be
asked now thanks to the new knowledge gained by the discoveries made by our
predecessors and could not have been anticipated in 1911.
I am convinced that Ernest Solvay and Hendrik Lorentz would not be disappointed
in learning that the end of physics did not occur 30 years after the foundation
of the Institutes. They would share our excitement in trying to answer
the new questions that enlarge further our vision of the universe. They would be
delighted to see that the same enthusiasm and passion for understanding natural
phenomena animate today’s researchers as they inhabited the participants of the
1911 Conference.
We can now start our work. I would like to thank all of you for your positive
answer to our invitation and for being with us today. I would also like to thank the
rapporteurs, the session chairs and, of course, our conference chair David Gross, for
all the preparation work that went into this meeting. Finally, as you can see, we
have tried to arrange the conference room in a way that recalls the setting of the
early days.
Thank you very much for your attention.