Interested in thoughts on this excerpt from Martin Rees

From: Danny Mayes <>
Date: Wed, 26 Jul 2006 00:29:19 -0400

Which approximates my ideas on the nature of reality and the possible role
of intelligence.


(MARTIN REES:) This is a really good time to be a cosmologist, because in
the last few years some of the questions we've been addressing for decades
have come into focus. For instance, we can now say what the main ingredients
of the universe are: it's made of 4% atoms, about 25% dark matter, and 71%
mysterious dark energy latent in empty space. That's settled a question that
we've wondered about, certainly the entire 35 years I've been doing

We also know the shape of space. The universe is 'flat'-in the technical
sense that the angles of even very large triangles add up to 180 degrees.
This is an important result that we couldn't have stated with confidence two
years ago. So a certain phase in cosmology is now over.

But as in all of science, when you make an advance, you bring a new set of
questions into focus. And there are really two quite separate sets of
questions that we are now focusing on. One set of questions addresses the
more 'environmental' side of the subject-we're trying to understand how,
from an initial Big Bang nearly 14 billion years ago, the universe has
transformed itself into the immensely complex cosmos we see around us, of
stars and galaxies, etc.; how around some of those stars and planets arose;
and how on at least one planet, around at least one star, a biological
process got going, and led to atoms assembling into creatures like
ourselves, able to wonder about it all. That's an unending quest-to
understand how the simplicity led to complexity. To answer it requires ever
more computer modeling, and data in all wavebands from ever more sensitive

Another set of questions that come into focus are the following:

* Why is the universe expanding the way it is?
* Why does it have the rather arbitrary mix of ingredients?
* Why is it governed by the particular set of laws which seem to
prevail in it, and which physicists study?

These are issues where we can now offer a rather surprising new perspective.
The traditional idea has been that the laws of nature are somehow unique;
they're given, and are 'there' in a platonic sense independent of the
universe which somehow originates and follows those laws.

I've been puzzled for a long time about why the laws of nature are set up in
such a way that they allow complexity. That's an enigma because we can
easily imagine laws of nature which weren't all that different from the ones
we observe, but which would have led to a rather boring universe-laws which
led to a universe containing dark matter and no atoms; laws where you
perhaps had hydrogen atoms but nothing more complicated, and therefore no
chemistry; laws where there was no gravity, or a universe where gravity was
so strong that it crushed everything; or the lifetime was so short that
there was no time for evolution.

It always seemed to me a mystery why the universe was, as it were,
'biophilic'-why it had laws that allowed this amount of complexity. To give
an analogy from mathematics, think of the Mandelbrot Set; there's a fairly
simple formula, a simple recipe that you can write down, which describes
this amazingly complicated pattern, with layer upon layer of structure. Now
you could also write down other rather similar-looking recipes, similar
algorithms, which describe a rather boring pattern. What has always seemed
to me a mystery is why the recipe, or code, that determined our universe had
these rich consequences, just as the algorithms of the Mandelbrot set rather
than describing something rather boring, in which nothing as complicated as
us could exist.

For about 20 years I've suspected that the answer to this question is that
perhaps our universe isn't unique. Perhaps, even, the laws are not unique.
Perhaps there were many Big Bangs which expanded in different ways, governed
by different laws, and we are just in the one that has the right conditions.
This thought in some respect parallels the way our concept of planets and
planetary systems has changed.

People used to wonder: why is the earth in this rather special orbit around
this rather special star, which allows water to exist or allows life to
evolve? It looks somehow fine-tuned. We now perceive nothing remarkable in
this, because we know that there are millions of stars with retinues of
planets around them: among that huge number there are bound to be some that
have the conditions right for life. We just happen to live on one of that
small subset. So there's no mystery about the fine-tuned nature of the
earth's orbit; it's just that life evolved on one of millions of planets
where things were right.

It now seems an attractive idea that our Big Bang is just one of many: just
as our earth is a planet that happens to have the right conditions for life,
among the many many planets that exist, so our universe, and our Big Bang,
is the one out of many which happens to allow life to emerge, to allow
complexity. This was originally just a conjecture, motivated by a wish to
explain the apparent fine-tuning in our universe-and incidentally a way to
undercut the so-called theological design argument, which said that there
was something special about these laws.

But what's happened in the last few years, and particularly sin the last
year, is that the basis for this so-called multiverse idea has strengthened,
and, moreover, the scale which we envisage for the multiverse has got even
vaster than we had in mind a few years ago. There's a firmer basis for the
'multiverse' concept because recent work on the best theory we have for the
fundamental laws of nature, namely superstring theory, suggests that there
should indeed be many possible forms for a universe, and many possible laws
of nature.

At first it was thought that there might be just one unique solution to the
equations, just one possible three-dimensional universe with one possible
'vacuum state' and one set of laws. But it seems now, according to the
experts, that there could be a huge number. In fact Lenny Susskind claims
that there could be more possible types of universe than there are atoms in
our universe-a quite colossal variety. The system of universes could be even
more intricate and complex than the biosphere of our planet. This really is
a mind-blowing concept, especially when we bear in mind that each of those
universes could themselves be infinite.

At first sight you might get worried about an infinity of things in
themselves infinite, but to deal with this you have to draw on a body of
mathematics called transfinite number theory, that goes back to Cantor in
the 19th century. Just as many kinds of pure mathematics have already been
taken over by physicists, this rather arcane subject of transfinite numbers
is now becoming relevant, because we've got to think of infinities of
infinity. Indeed, there's perhaps even a higher hierarchy of infinities: in
addition to our universe being infinite, and there being an infinite number
of possible laws of nature, we may want to incorporate the so-called many
worlds theory of quantum mechanics.

Each 'classical' universe is then replaced by an infinite number of
super-imposed universes, so that when there's a quantum choice to be made
the path forks into extra universes. This immensely complicated construct is
the consequence of ideas that are still speculative but are firming up. One
of the most exciting frontiers of 21st century physics, is to utilize the
new mathematics and the new cosmology to come to terms with all this.

What we've traditionally called 'our universe' is just a tiny part of
something which is infinite, so allows for many replicas of us elsewhere (in
our same space-time domain, but far beyond the horizon of our observations),
but even that infinite universe is just one element of an ensemble that
encompasses an infinity of quite different universes. So that's the pattern
adumbrated by cosmology and some versions of string theory. What we have
normally called the laws of nature are not universal laws-they're just
parochial by-laws in our cosmic patch, no more than that, and a variety of
quite different regimes prevail elsewhere in the ensemble.

One thing which struck me recently, and I found it a really disconcerting
concept, was that once we accept all that, we get into a very deep set of
questions about the nature of physical reality. That's because even in our
universe, and certainly in some of the others, there'd be the potential for
life to develop far beyond the level it's reached on earth today. We are
probably not the culmination of evolution on earth; the time lying ahead for
the earth is as long as the time it's elapsed to get from single-celled
organisms to us, and so life could spread in a post-human phase far beyond
the earth. In other universes there may be an even richer potentiality for
life and complexity.

Now life and complexity means information-processing power; the most complex
conceivable entities may not be organic life, but some sort of
hyper-computers. But once you accept that our universe, or even other
universes, may allow the emergence within them of immense complexity, far
beyond our human brains, far beyond the kind of computers we can conceive,
perhaps almost at the level of the limits that Seth Lloyd discusses for
computers-then you get a rather extraordinary conclusion. These super or
hyper-computers would have the capacity to simulate not just a simple part
of reality, but a large fraction of an entire universe.

And then of course the question arises: if these simulations exist in far
larger numbers than the universe themselves, could we be in one of them?
Could we ourselves not be part of what we think of as bedrock physical
reality? Could we be ideas in the mind of some supreme being, as it were,
who's running a simulation? Indeed, if the simulations outnumber the
universes, as they would if one universe contained many computers making
many simulations, then the likelihood is that we are 'artificial life' in
this sense. This concept opens up the possibility of a new kind of 'virtual
time travel', because the advanced beings creating the simulation can, in
effect, rerun the past. It's not a time-loop in a traditional sense: it's a
reconstruction of the past, allowing advanced beings to explore their

All these multiverse ideas lead to a remarkable synthesis between cosmology
and physics, giving substance to ideas that some of us had ten or 20 years
ago. But they also lead to the extraordinary consequence that we may not be
the deepest reality, we may be a simulation. The possibility that we are
creations of some supreme, or super-being, blurs the boundary between
physics and idealist philosophy, between the natural and the supernatural,
and between the relation of mind and multiverse and the possibility that
we're in the matrix rather than the physics itself.

Once you accept the idea of the multiverse, and that some universes will
have immense potentiality for complexity, it's a logical consequence that in
some of those universes there will be the potential to simulate parts of
themselves, and you may get sort of infinite regress, so we don't know where
reality stops and where the minds and ideas take over, and we don't know
what our place is in this grand ensemble of universes and simulated


Considerations of the multiverse change the way we think about ourselves and
our place in the world. Traditional religion is far too blinkered to
encompass the complexities of mind and cosmos. All we can expect is to have
a very incomplete and metaphorical view of this deep reality. The gulf
between mind and matter is something we don't understand at all, and some
minds can evolve to the stage that they can create other minds, there's real
blurring between the natural and the supernatural.

My attitude towards religion is really two-fold. First, as far as the
practice of religion is concerned, I appreciate it and participate in it,
but I'm skeptical about the value of interactive dialogue There's no
conflict between religion and science (except, of course, with naive
creationism and suchlike) , but I doubt-unlike some members of the Templeton
Foundation-that theological insights can help me with my physics. I'm
fascinated to talk to philosophers (and with some theologians) about their
work, but I don't believe they can help me very much. So I favor peaceful
coexistence rather than constructive dialogue between science and theology


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Received on Wed Jul 26 2006 - 00:31:12 PDT

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