There is a very peculiar hypothesis that keeps recurring in
public discussions among scientists. It
is very speculative, but also, very thought-provoking. It concerns the idea that the physical
reality in which we live is a computer simulation. By extension, we ourselves could be simulated
creatures, products of a computer and the simulation program it runs.
While that notion is preposterous on many levels, it is
seriously discussed by many people whose intellects dwarf mine, and so, it
deserves discussion, if only as a philosophical exercise—a useful one at that.
One of the first questions which challenges the Computer
Simulation Hypothesis is, if we are simulated creatures, then who simulated
us, and to a further point, are they themselves simulations? To ask another way, is there an ultimate Simulator?
It all comes down to questions of the ultimate, absolute
fundamental reality of, well, of reality itself.
One of the supporting arguments for our being in a
simulation, is that the physical universe we observe, does behave in many
respects as if it were designed, as if it were programmed, as if it followed
rules and instructions. Dr. Max Tegmark,
a physicist, has remarked that the universe obeys mathematical rules so
thoroughly, that he concludes that reality is math itself.
In regard to discussing such rules, however, we diverge into
the theory of Intelligent Design, specifically design by a fundamental
creative force or agent, and then we quickly merge into theology, a field at
which physicalist theory scoffs.
The greatest obstacle to the computer simulation hypothesis
is the fact of our consciousness. It
must be clarified that the term consciousness is used here in the very specific
context of our inward consciousness, our self-perception of our
self-perception. Inward consciousness is
the only observed reality which perceives itself. It does so from within itself. Physics has no explanation for it beyond some
vague concepts of emergent properties, but such concepts are far removed from
our experience of consciousness.
As the late JBS Haldane said, if our consciousness were the
product solely of physical matter, then we would have no way of knowing
that. That is because physics, not
conscious reason, would determine our every thought (and word and deed). We would think and believe only according to
the dictates of unconscious, deterministic laws of physics, whether or not
those thoughts and beliefs were correct.
Were such the case, we would be observers of, not volitional
participants in, our own lives.
The paradox would be, that the very fact of something being true,
would prevent us from knowing that it is true.
Truth itself would obscure truth.
Consciousness, its inward reality, is a perplexing
mystery. It is not only the greatest
unsolved question of science, it is arguably, by its very nature, forever
beyond the ability of science to understand.
The famous phrase of Renee Descartes, “I think, therefore I
am,” has many levels of meaning. One of
them is that, the one and only fact of which we can be absolutely certain is
that we are conscious. Every other fact
comes to us through our senses, such as sight and hearing, but all our senses
are subject to error, such as optical illusions. Nobody, however, can think he is conscious
unless he is.
The philosophy of Idealism goes so far as to claim
that the only fundamental reality is consciousness itself. There are many branches and implications
arising from that claim, but let us return to the simulation hypothesis.
How did the simulation hypothesis ever become a
matter of serious discussion?
With the advent of the computer revolution, technology has
changed so dramatically that it is difficult to overstate the effects of
computerization. Computers can process
tremendously vast amounts of data in fractions of a second. They can work on difficult problems 24 hours
a day without pause, producing vast amounts of information.
One category of the projects that has been tackled by
computers is that of simulations.
For example, weather forecasting involves calculations using complex
bodies of atmospheric measurements.
Another project has been to predict the movements of planets within our
solar system, and to predict the movements of stars within our galaxy, and even
the motions of galaxies throughout the observable universe.
As our knowledge of astronomy has increased, it has been
discovered that there are many billions of planets in our galaxy, and
presumably in other galaxies. It
naturally follows that we might expect some of those planets will contain
technologically advanced life forms. If
that expectation is justified, then we may find that some life form somewhere
has developed a super-computer, one so unimaginably powerful, that it can
simulate not only the movements of planets and stars and galaxies, but even of
atoms and their subatomic particles—and do so on the scale of our known
universe.
It is in this context that some scientists have developed
the idea that, not only do we produce simulations (however primitive by
comparison), but that we might ourselves be the product of hyper-advanced
simulations.
The human brain has been compared to computers, and like
computers, the brain can create models of reality. These mental models might loosely be compared
to simulations.
Physical science regards the human brain as being the seat
of conscious thought and perception.
There is, of course, a clear correlation between the brain and
thought. Far less clear, however, is
whether the brain gives rise to consciousness, or just hosts it. The brain is composed of atoms, and atoms are
not considered to be conscious. Science
has not been able to bridge the gap between unconscious matter and
consciousness, so the role of the brain, in inward consciousness, might
be as a repository rather than as a source.
Regardless, it does seem likely that the brain’s mechanism
for understanding our physical surrounding is to simulate it. How the brain might do this is poorly
understood, if at all. Can the brain
understand itself? Can the brain
simulate itself? Might the principle of
self-similarity have something to do with it?
One might say that our understanding of the universe itself
is based in a mental image, a mental simulation of the cosmos.
All this, of course, forces us to ask what, exactly, is a
simulation?
Skipping over many important unknowns, we might ask, can the
universe be a simulation of itself?
Is the universe itself a computer?
The question contains some absurdities, because computers do
not exist in isolation. They have to be
designed and manufactured. They have to
serve a purpose. They rely on inputs
from the outside, and they produce outputs for an external user. Those outputs have to be formatted in a way
that is useful to the user. All of this
requires that the computer be properly programmed. Therefore, a computer is not just a thing
unto itself, it is a holistic system designed by and for humans.
Despite all that, the universe can be considered to be, at
least in some sense, a computer, one that may exist in isolation from all
external inputs, and from any external user.
Such a reality would be an entirely closed system. Even if one posits many universes, then those
many universes would comprise a multi-verse, and that multi-verse would be its
own closed system.
Such a contraption, if I may call it that, requires a
physicalist outlook for anyone to believe in its possibility. In short, physicalism is the paradigm that
everything in the material world can be explained by the material world, with
no need for anything outside the material world. Indeed, it holds that there is
nothing outside, or that there is no outside, at least nothing that has any
effect on our closed system.
Therefore, if the universe is considered to be a computer,
we must carefully avoid the inherent absurdities which may arise. We must ask, who made the computer? From what materials? We must ask, from where is the data
imported? Who wrote the program? What defines the output? In other words, our simulated world is not a
closed system.
Even if we dismiss the simulation hypothesis out of hand, we
might note that the behavior of subatomic particles seems to mimic certain
programming techniques that are employed in computers. One of them is that one can sometimes reduce
the need for storing data in separate locations for each and every data
bit.
One of the methods of doing this is to use statistical
computations. For example, in the
physical universe, we know that half of all uranium atoms (of a given isotope)
decay every period of time called its half-life. It is not possible to say exactly which atoms
will decay when, but after X number of years, half of them will have done
so. Therefore, each atom of U238 has a
fifty-percent chance of decaying during the next X number of years (where X
equals 4.468 billion). That decay could
occur, or not occur, at any moment, for each atom. (Each atom decays independently of the
others.)
If one were to create a simulated universe in a computer, he
would not need to encode in a separate memory cell, each uranium atom, but
simply apply a decay formula.
But why do those atoms (of U236) decay?
There are two explanations for why each and every object in
the universe behaves in exactly the way it does. One of them is the simulation hypothesis,
which is the topic of this commentary.
The other is natural law.
Each thing in the universe obeys natural law, because each thing is part
of the overall scheme of nature. Natural
law is not the same as human law. It is
not as if nature wrote down the speed of light, or the strength of gravity, and
so forth. All natural laws are really
one natural law. That natural law
governs how each thing in the universe interacts with each other thing in
nature. Furthermore, it is not exactly
clear that any one thing in the universe is entirely separate from any other
thing.
We must also apply these thoughts to the simulation
hypothesis. The computer in which we
supposedly exist, must also obey natural law, perhaps the identical law which
it simulates.
As one can quickly see, the philosophical can of worms has
been opened, and there may be no way to get all the worms back in the can.
