December 04, 2006

The Reading Argument

The Reading Argument: Why the Probability that You Are Living in a Novel is Quite High

Sonny Moonie

(A parody of:

The Simulation Argument: Why the Probability that You Are Living in a Matrix is Quite High

Nick Bostrom

Times Higher Education Supplement, May 16, 2003)

The Simulation Argument had many otherwise naturally philosophical minds ruminating on the artificiality of reality. Picture the scenario of that essay for ridicule: our own minds assumed to exist possibly only as simulations in a computer programmed to amuse a relatively wealthy extraterrestrial individual, just to probe such questions as whether terrestrial civilization will ever achieve that libertarian tranhumanist fantasy.

However, a serious line of reasoning from a related, more plausible scenario leads to a striking conclusion about the world we live in. I call this the reading argument. Perhaps its most startling lesson is that there is a significant probability that you are living in the reading of a novel. I mean this literally: if the reading hypothesis is true, you exist in an imagined world read in a novel written by some advanced civilization. Your body, too, is merely a detail of that reading. What grounds could we have for taking this hypothesis seriously? Before getting to the gist of the reading argument, let us consider some of its preliminaries. One of these is the assumption of “substrate independence”. This is the idea that conscious minds could in principle be implemented not only on intrinsically unconscious substrates (such as the carbon-based biochemistry inside you or silicon-based electronics inside artificially intelligent computers) but also on some other computational substrate such as another conscious mind.

Of course, the minds we have today are not powerful enough to visualize all the mental processes that take place in your life. Even if they were, we wouldn’t know how to write a novel that lets them do it. But ultimately, what allows you to have conscious experiences is not the fact that your brain is made of squishy, biological matter but rather that it implements a certain computational architecture. This assumption is quite widely (although not universally) accepted among cognitive scientists and philosophers of mind. For the purposes of this article, we shall take it for granted.

Given substrate independence, it is in principle possible to emulate a human mind with a sufficiently intelligent other mind. Doing so would require very high powers of concentration that we do not yet have. It would also require advanced authorial abilities, or sophisticated ways of writing a very detailed factual biography of a human being which advanced novelists could then fictionalize. Although we will not be able to do this in the near future, the difficulty appears to be merely literary. There is no known physical law or material constraint that would prevent a sufficiently literarily advanced civilization from implementing human minds in a novel.

Our second preliminary is that we can estimate, at least roughly, how long a book it would take to implement a human mind along with a virtual reality that would seem completely realistic for it to interact with. Furthermore, we can establish lower bounds on how thick the novels of an advanced civilization could be. Literary futurists have already produced designs for imaginarily possible libraries of books that could be published using advanced molecular printing technology. The upshot of such an analysis is that a literarily mature civilisation that has developed at least those technologies that we already know are physically possible, would be able to write books long enough to describe an astronomical number of human-like lives, even if only a tiny fraction of their pages were used for that purpose.

If you are such a character in a novel, there might be no direct observational way for you to tell; the virtual reality that you would be living in would look and feel perfectly real. But all that this shows, so far, is that you could never be completely sure that you are not living in a reading. This result is only moderately interesting. You could still regard the reading hypothesis as too improbable to be taken seriously.

Now we get to the core of the reading argument. This does not purport to demonstrate that you are in a reading. Instead, it shows that we should accept as true at least one of the following three propositions:

(1) The chances that a species at our current level of development can avoid going extinct before becoming literarily mature is negligibly small

(2) Almost no literarily mature civilizations are interested in reading and writing books about minds like ours

(3) You are almost certainly in a reading.

Each of these three propositions may be prima facie implausible; yet, if the reading argument is correct, at least one is true (it does not tell us which).

While the full reading argument would employ some critical theory and wordiness, the gist of it can be understood in pseudoscientific terms. Suppose that proposition (1) is false. Then a significant fraction of all species at our level of development eventually becomes literarily mature. Suppose, further, that (2) is false, too. Then some significant fraction of these species that have become literarily mature will use some portion of their library resources to read novels about minds like ours. But, as we saw earlier, the number of read about minds that any such literarily mature civilisation could cause to exist is astronomically huge.

Therefore, if both (1) and (2) are false, there will be an astronomically huge number of read into existence minds like ours. If we work out the numbers, we find that there would be vastly many more such characterized minds than there would be non-fictional minds possessing organic bodies. In other words, almost all minds like yours, having the kinds of experiences that you have, would be fictional rather than real. Therefore, by a very weak principle of indifference, you would have to think that you are probably one of these fictional characters rather than one of the exceptional ones that possess real biological parts.

So if you think that (1) and (2) are both false, you should accept (3). It is not coherent to reject all three propositions. In reality, we do not have much specific information to tell us which of the three propositions might be true. In this situation, it might be reasonable to distribute our credence roughly evenly between the three possibilities, giving each of them a substantial probability.

Let us consider the options in a little more detail. Possibility (1) is relatively straightforward. For example, maybe there is some highly dangerous literary theory that every sufficiently advanced civilization develops, and which then destroys its culture. Let us hope that this is not the case.

Possibility (2) requires that there is a strong convergence among all sufficiently advanced civilizations: almost none of them is interested in reading or writing books about minds like ours, and almost none of them contains any relatively wealthy individuals who are interested in doing that and are free to act on their desires. One can imagine various reasons that may lead some civilizations to forgo reading novels, but for (2) to obtain, virtually all civilizations would have to do that. If this were true, it would constitute an interesting constraint on the future evolution of advanced intelligent life.

The third possibility is the philosophically most intriguing. If (3) is correct, you are almost certainly now living in the reading of a book that was created by some advanced civilization. What kind of empirical implications would this have? How should it change the way you live your life?

Your first reaction might think that if (3) is true, then all bets are off, and that one would go crazy if one seriously thought that one was living in a fiction.

To reason thus would be an error. Even if we were in a novel, the best way to predict what would happen next in our story is still the ordinary methods – extrapolation of past trends, scientific modelling, common sense and so on. To a first approximation, if you thought you were in a novel, you should get on with your life in much the same way as if you were convinced that you are living a non-fictionalized life at the ground level of reality.

The reading hypothesis, however, may have some subtle effects on rational everyday behaviour. To the extent that you think that you understand the motives of the authors, you can use that understanding to predict what will happen in the fictional world they created. If you think that there is a chance that the author of this world happens to be, say, a true-to-faith descendant of some contemporary Christian fundamentalist, you might conjecture that he or she has set up the story in such a way that the fictional characters will be rewarded or punished according to Christian moral criteria. An afterlife would, of course, be a real possibility for a fictional creature (who could either be continued in a different story after her death or even be transferred into the simulator’s universe by being provided with the temporary use of an actress's real body there). Your fate in that afterlife could be made to depend on how you behaved in your present fictional publication. Other possible reasons for writing novels include the artistic, scientific or recreational. In the absence of grounds for expecting one kind of novel rather than another, however, we have to fall back on the ordinary empirical methods for getting about in the world.

If we are just in a novel, is it possible that we could know that for certain? If the novelists don’t want us to find out, we probably never will. But if they choose to reveal themselves, they could certainly do so. Maybe an essay informing you of the fact would pop up in front of you, or maybe they would “write” you into their world. Another event that would let us conclude with a very high degree of confidence that we are in a fiction is if we ever reach the point where we are about to visualize our own literary characters exactly equivalent to human lives. If we start reading full characters, that would be very strong evidence against (1) and (2). That would leave us with only (3).

(Nick Bostrom is a British Academy postdoctoral fellow in the philosophy faculty at Oxford University. His simulation argument is published in The Philosophical Quarterly. A preprint of the original paper is available at

(Sonny Moonie is the pseudonymous author of this close parody which makes it possible to visualize a modern presentation of an old idea that is not exactly his own opinion, but may be imagined as being held by some fictional character.)

The Body of
B Franklin Printer,
(Like the Cover of an old Book
Its Contents torn out
And stript of its Lettering and Gilding)
Lies here, Food for Worms.
But the work shall not be lost;
For it will, (as he believ'd) appear once more,
In a new and more elegant Edition
Revised and corrected
By the Author.

"Epitaph," Benjamin Franklin

[I wrote all of the above by March 9, 2004. I think someone else has done a "novel argument" in response to the "simulation argument," and I'm trying to find it. Some famous writer said you're supposed to burn all your backstory when you become a writer, and I agree, but I think this still holds up as funny, and it's just a word-substitution parody, and I haven't really become a writer yet if I'm still using a pseudonym.]

[I found the "novel argument" I was looking for. It's by Rudy Rucker, whose blog I found via Mac Tonnies' blog Posthuman Blues. Rudy's answer to the question at Edge in 2005: "What Do You Believe Is True Even Though You Cannot Prove It?" is approximately that the universe has multiple revisions like a novel, not necessarily that it is any more like a novel.]