Faculty of Philosophy, Oxford University
from Simulation-Argument Website
Children dying of AIDS; lovers separated by war and poverty; cancer patients tormented by unbearable pain; stroke victims deprived of their use of language and reason…
One would think nobody but a sadist could have the imagination to think up these horrors, much less possess the desire to create a world that contains them in such abundance.
But the machines did it, at least that’s
how the story goes.
Indeed, as the story goes, they tried that, but supposedly it didn’t work.
The existence of unnecessary evil is one of the most powerful arguments against the belief that the world was created by an all-powerful, all-knowing, and perfectly good God.
Theologians have spent centuries trying to answer it, and with very questionable success.
But the problem of evil is only a
problem if one assumes that the world was created by an omnipotent
and perfectly good being. If one assumes instead that the creator
was not perfectly good, and perhaps not even omnipotent, then it
would be much easier to reconcile the view that our world was
created with its seemingly obvious ethical shortcomings.
But what if you had the ability to
create this kind of Matrix, would you do it? Even if you would not
have chosen to create a world like this, there are many other people
who do not share your scruples. If these people had the ability to
create Matrices, some of their works might well look like the world
in which we find ourselves.
But perhaps future historians would create a Matrix that mimicked the history of their own species. They might do this to find out more about their past, or to explore counterfactual historical scenarios. In the world of the Architect(s), Napoleon may have succeeded in conquering Europe, and our world might be a Matrix created to research what would have happened if Napoleon had been defeated.
Or perhaps there will be future artists who create Matrices as an art form much like we create movies and operas. Or perhaps the tourist industry will create simulations of interesting historical epochs so that their contemporaries can go on themed holidays to some bygone age by entering into the simulation and interacting with its inhabitants.
The possible motives are myriad, and if
future people are anything like present people, and if they have the
technological might and the legal right to create Matrices, we would
expect that many Matrices would be created, including ones that
would look like the world that we are experiencing.
If this were the case, where would you most likely be? The so-called Simulation argument, which I introduced a few years ago, makes this line of reasoning more precise and takes it to its logical conclusion.
The conclusion is that there are three basic possibilities at least one of which is true.
Why? Because if the first two possibilities are not the case, then there are more “people” living in Matrices than in “real worlds.”
As a “person” then the chances are that you are living in a Matrix rather than in a “real world.” The Simulation argument does not tell us which of these three possibilities obtain, only that at least one of them does.
The argument employs some math and probability theory, but the basic idea can be understood without recourse to technical apparatus.
Many philosophers and cognitive
scientists believe that such brain-simulations would be conscious,
provided the simulation was sufficiently detailed and accurate.
While these estimates are very approximate, it turns out that even when allowing for a large margin of error, the computational resources of a mature civilization would suffice to create very many Matrices.
Even a single planetary-sized computer, constructed with advanced molecular nanotechnology, could simulate the entire mental history of humankind by using less than one millionth of its computing power for one second; and this presupposes only already known computational mechanisms and engineering principles.
A single civilization may eventually build millions of such computers.
We can conclude that a technologically
mature civilization would have enough computing power such that even
if it devoted but a tiny fraction of it to creating Matrices, there
would soon be many more simulated people than there were people
living in the original history of that civilization.
If the book you are holding in your hands is a simulated book, the simulation would only need to include its visual appearance, its weight and texture, and a few other macroscopic properties, because you have no way of knowing what its individual atoms are doing at this moment. If you were to study the book more carefully, for example by examining it under a powerful microscope, additional details of the simulation could be filled in as needed. Objects that nobody is perceiving could have an even more compressed representation.
Such simplifications would dramatically reduce the computational requirements.
Consider the set of civilizations that are at similar level of technological development as our own current civilization. Suppose that some non-trivial fraction of these eventually go on to become technologically mature. Suppose, furthermore, that some non-trivial fraction of these devote a non-negligible proportion of their resources to building Matrices.
Then most people like us live in Matrices rather than outside them.
There are thus three basic
possibilities: either almost every civilization like ours go extinct
before reaching technological maturity; or almost every mature
civilization lacks any interest in building Matrices; or almost all
people with our kind of experiences live in Matrices.
Presumably, Architects would have used their advanced technology to improve their own capacities, so they may be super-intelligent and have complete control over their own mental states. Rather than resorting to Matrix-building for recreation, they may obtain pleasure more efficiently by direct stimulation of their brains’ pleasure centers.
Their science may be so advanced that they have little to learn from running simulations of their historical past.
Furthermore, they might develop ethical
norms that prohibit the creation of Matrices. So we cannot infer
from the fact that many current people would be tempted to construct
Matrices that the same would hold for the super-advanced folks that
would actually have the ability to act on this motive.
Unless we had some specific evidence to the contrary, we would therefore have to conclude that the world we see around us exists only by virtue of being simulated on a powerful computer built by some technologically highly advanced Architect.
Descartes (1596-1650) posed this question in his Meditationes, and considered the scenario where a hypothetical evil demon caused us to have erroneous beliefs about external objects.
In more recent years, Descartes’ skeptical scenario has been given a more modern finish, and instead of a demon one is now asked to imagine a mad scientist who has extracted one’s brain and who keeps it in a vat where the scientist is stimulating it with electrical signals replicating the sensory input that the brain would have had if it had interacted with a very different environment from that which is present in the real world.
This is, of course, is the predicament
explored in the Matrix movie. How can one possibly know that
one is not such a brain in a vat, the philosophical skeptic
challenges, given that all the appearances we experience could be
the experiences of an envatted brain? (see
the brain in a vat)
The traditional skeptical argument offers no positive ground for thinking that we are living in a Matrix. At best, it shows that we cannot completely rule out that possibility, but we remain free to assign it a very small or negligible probability. If there are no mad scientists who experiment on conscious envatted human brains, then we are not envatted.
Even if there were a few such
brains-in-vats, they might be extremely rare compared to the
brains-in-crania that interact with the external world in the normal
way; and if so, then it may be highly unlikely that we would be
among the envatted ones.
From this we can then conclude that
either technologically mature civilizations that are interested in
creating Matrices are extremely rare compared to civilizations at
our own current stage of development or almost all people like us
live in Matrices. And from this, the division into three the three
basic possibilities mentioned above follows.
We might still think that the probability is less than 50%.
A degree of belief of something like 20% would seem quite reasonable given our current information.
They know there are many Matrices. They lead parts of their lives inside a Matrix. They know that most of their compatriots spend their whole lives in a Matrix. Given this, they should be extremely reluctant to think that they have escaped their Matrix. What appears to be an escape could easily just be simulated escape, so that they exit one level of the Matrix only to reemerge at another.
Wachowski brothers can of course
stipulate that this is not the case and that the heroes really do
get to experience “real” reality. But if Neo were rational, he would
never be able to be at all confident that this is what happens.
For if we develop the capability to create our own Matrices, and if we decide to make use of this capability, we would obtain very strong evidence against the first two possibilities:
This would leave us with only the third possibility - that we almost certainly inhabit a Matrix.
Certainly, if the Architects of a Matrix wished to reveal themselves, it would be easy enough for them to do so.
For example, they could make a window
pop up in our visual field with the text “YOU ARE LIVING IN A
MATRIX. CLICK HERE FOR MORE INFORMATION”.
Déjà vu is a sign of a glitch in the Matrix, which is re-running a sequence to cover something that has changed.
Some people have written to me that they have found signs that we are in a Matrix. One person, for instance, told me that he could see flickering pixels when he looked in his bathroom mirror. Another person wrote that he could hear voices in his head. But even if we are in a Matrix, it is far more likely that such phenomena are the result of imperfections in the reporters rather than in the Matrix itself.
There are many perfectly ordinary
explanations for why some people should report having these kinds of
experiences, including mental illness, over-excited imagination,
gullibility, and so forth. Dysfunctional brains could be simulated
just as easily as properly functioning ones, and including them in
the simulation may indeed add to its verisimilitude.
Even if some people did notice an anomaly, the Architect could backtrack the simulation a few seconds and rerun it in a way that avoided the anomaly entirely or else could simply edit out the memory of the anomaly from whoever had noticed something suspect.
But in fact we know almost nothing about what these motives might be. Because of this ignorance, our best method for getting around in our Matrix (if that is where we are) is to study the patterns we find in the world we experience. We would run experiments, discover regularities, build models, and extrapolate from past events.
In other words, we would apply the
scientific method and common sense in the same way as if we knew
that we were not in a Matrix. To a first approximation, therefore,
the answer to how you should live if you are in a Matrix is that
you should live the same way as if you are not in a Matrix.
For instance, while the physical world
cannot suddenly pop out of existence, a simulated reality could do
so at any time if the Architect decides to pull the plug. An
afterlife would also be a real possibility. When a person dies in a
simulation, he or she could be resurrected in another simulation, or
the Architect could uplift the deceased into his own level of
The so-called “problem of other minds” - how we can know that other people are really conscious and are not just behaving as if they were - is another old chestnut of philosophy.
There is, however, no consensus that such “zombie” people are possible even in principle.
have argued that it is necessarily true that anybody who acts
sufficiently like a normal human being must also have conscious
experience. (Whether this view would entail that your least favorite
politicians cannot be zombies is a question on which more research
The computer and the electrical activity of its circuitry would be physical phenomena in the more basic level of reality inhabited by the Architect of the Matrix.
Was there a Matrix on top of the Matrix? As Revolutions revealed, there was not. But there could have been.
A mature civilization would have enough computing power to run astronomically many Matrices. If we are in a Matrix, therefore, there are probably vast numbers of other Matrices, which differ from ours in some detail or in their overall design. These other Matrices may be run sequentially, as in the movie, or simultaneously by time-sharing the same processor or by using multiple computers.
From the viewpoint of the simulated
inhabitants, it makes little difference how the Matrices are
Since all the higher levels of
simulation would ultimately be implemented on this Architect’s
computer, he would have to shoulder the cost of all the simulations
and all the simulated people. If his computing power is limited,
there may be only a small number of levels.
If we combine this insight with the speculation that moral considerations may play a part in determining the treatment some simulated people receive at the hands of their Architects, we are led to the peculiar thought that everybody - not just the simulated people - may have a self-interested reason for behaving morally.
If behaving morally towards somebody includes judging and treating them according to moral criteria, this could further strengthen the reason that everybody have for behaving morally.
The stronger that reason is, the more we
would expect that people would be motivated by it. And the more
people are likely to be motivated to treating their simulated
creatures morally, the stronger this reason would become. This
reasoning can be iterated indefinitely in a truly “virtuous circle,”
albeit a rather tenuous one as it relies not only on the possibility
that we are in a simulation but also on tenuous speculations about
the motives of the Architects.
When we follow through the logical
implications of what we think we know, we discover just how much we
don’t yet know.