Thought Experiments:
Science Fiction as a Window intoPhilosophical Puzzles
Let us open the door to age-old questions about our very nature, the nature of the universe, and whether there are limits to what we, as humans, can understand. But as old as these issues are, let us do something relatively new - let us borrow from the world of science fiction thought experiments to fire the philosophical imagination. Good science fiction rarely disappoints; good philosophy more rarely still.
Thought experiments are imagination’s fancies; they are windows into the fundamental nature of things. A philosophical thought experiment is a hypothetical situation in the “laboratory of the mind” that depicts something that often exceeds the bounds of current technology or even is incompatible with the laws of nature, but that is supposed to reveal something philosophically enlightening or fundamental about the topic in question. Thought experiments can demonstrate a point, entertain, illustrate a puzzle, lay bare a contradiction in thought, and move us to provide further clarification. Indeed, thought experiments have a distinguished intellectual history. Both the creation of relativity and the interpretation of quantum mechanics rely heavily upon thought experiments. Consider, for instance, Einstein’s elevator and Schrödinger ’s cat. And philosophers, perhaps even more than physicists, make heavy use of thought experiments. René Descartes, for instance, asked us to imagine that the physical world around us was an elaborate illusion. He imagined that the world was merely a dream or worse yet, a hoax orchestrated by an evil demon bent on deceiving us. He then asked: how can we really be certain that we are not deceived in either of these ways? (See Descartes’ piece in this volume, Chapter 4.) Relatedly, Plato asked us to imagine prisoners who had been shackled in a cave for as long as they can remember. They face a wall. Behind them is a fire. Between the prisoners and the fire is a pathway, where men walk, carrying vessels, statues and other objects (See Figure I.1.)
Fig. I.1 Plato’s cave
As the men walk behind the prisoners, they and the objects they carry cast shadows on the cave wall. The prisoners are thus not able to see the actual men and objects; their world is merely a world of shadows. Knowing nothing of the real causes of the shadows, the prisoners would naturally mistake these shadows for the real nature of things. Plato then asked: is this analogous to our own understanding of reality? That is, is the human condition such that our grasp of reality is only partial, catching only the slightest glimpse into the true nature of things, like the prisoners’ world of shadows?1
Intriguingly, if you read science fiction writers like Stanislaw Lem, Isaac Asimov, Arthur C. Clark and Robert Sawyer, you are already aware that some of the best science fiction tales are in fact long versions of philosophical thought experiments. From Clark’s 2001, which explored the twin ideas of intelligent design and artificial intelligence gone awry, to the Wachowski brothers’ Matrix films, which were partly inspired by Plato’s Cave, philosophy and science fiction are converging upon a set of shared themes and questions. Indeed, there is almost no end to the list of issues in science fiction that is philosophically intriguing. It is thus my modest hope that this short book isolates a number of key areas in philosophy where the interplay between philosophy and science fiction is especially rich. For instance, you might have seen the films AI o r I, Robot (or you may have read the stories they are derived from). And you might have asked:
• Can robots be intelligent? Should they have rights?
• Is artificial intelligence even possible?
Or you might have read a time travel story, such as H. G. Wells’s The Time Machine, and asked:
Is time travel possible? Indeed, what is the nature of space and time?
In this book, we delve into these questions, as well as many others, such as:
• Could I be deceived about the external world, as in The Matrix, or Vanilla
Sky?
• What is the nature of persons? For instance, can my mind survive the death of my body? Can I ‘upload’ my memories into a computer and somehow survive? (E.g., as in Mindscan.)
• Do we ever act freely, or is everything predetermined? (E.g., see Minority
Report.)
• Should we enhance our brains, and even change our very nature?
So let us see, in more detail, where our reflections will lead.
Part I: Could I be in a “Matrix” or Computer
Simulation?
Related Works: The Matrix; Permutation City; The 13th
Floor; Vanilla Sky; Total Recall; Animatrix
You sit here in front of this book. You are as confident that the book exists as you are of the existence of any physical object. The lighting is good; indeed, you feel the pages pressing on your hands - this is no illusion. But think of stories like The Matrix or Vanilla Sky . How can you really be sure that any of this is real? Perhaps you are simply part of a computer-generated virtual reality, created by an omnipotent supercomputer of unthinkable proportions. Is there some way to rule out such a scenario?
Our first section explores the aforementioned issue of the reality of the external world. Does the world around you - the people you encounter, the book you are now reading, indeed, even your hand - really exist? Answers to this question are a central focus of the sub-field of philosophy known as “epistemology,” or “theory of knowledge.” We begin with a brief science fiction story written by a philosopher, John Pollock, who depicts a “brain in a vat” scenario. Pollock’s thought experiment, like the works named in the section title listed above, invites reflection on a philosophical position known as “external world skepticism.” The skeptic about the external world holds that we cannot know that the external world that we believe is around us really exists, instead we may be in a dream, in virtual reality, and so on. Represented in this section are the aforementioned ideas of both Plato and Descartes; such provide essential philosophical background for this topic. While reading the pieces in the section, as well as other sections of the book, readers may wish to view or read one or more of the science fiction works named in the section titles. (Relatedly, instructors using this book for their courses may want their students to do so. In particular, they may consider screening the Star Trek episodes I list, as they are short, leaving time for in class discussion.)
The next piece in the section develops the issue of external world skepticism in a stunning new direction, suggesting that virtual reality science fiction thought experiments depict science fact. For philosopher Nick Bostrom has recently offered an influential argument that we are, in fact, in a computer simulation. He observes that assuming that a civilization survives long enough to be technologically sophisticated, it would likely be very interested in running simulations of entire worlds. In this case, there would be vastly more computer simulations, compared to
just one real world. And if this is so, there would be many more beings who are in a simulation than beings who are not. Bostrom then infers that given this, it is more likely than not that we are in a simulation. Even the seasoned philosopher will find Bostrom’s argument extremely thought provoking. Because the argument claims that it is more likely than not that we are in a simulation it does not rely on remote philosophical possibilities. To the skeptic, the mere possibility of deceit means that we cannot know the external world exists; for the skeptic holds that we must be certain of something in order to truly say that we know it. On the other hand, opponents of external world skepticism have argued that just because a skeptical scenario seems possible, it does not follow that we fail to know the external world exists. For knowledge doesn’t require certainty; the skeptic places too strong a requirement on knowledge. But Bostrom’s argument bypasses this anti-skeptical move: Even if you reject the claim that knowledge requires certainty, if his argument is correct, then it is likely that we are in a simulation. That the world we know is a computer simulation is no remote possibility - more likely than not, this is how the world actually is.
Part I also features a related piece by philosopher David J. Chalmers. In his “Matrix as Metaphysics” Chalmers uses the Matrix films as a means to develop a novel position on external world skepticism. Interestingly, Chalmers does not dispute Bostrom’s argument. Instead, he aims to deflate the significance of knowing we are in a simulation. Chalmers asks: why would knowing that we are in a simulation prove that the external world skeptic is correct? He writes:
I think that even if I am in a matrix, my world is perfectly real. A brain in a vat is not massively deluded (at least if it has always been in the vat). Neo does not have massively false beliefs about the external world. Instead, envatted beings have largely correct beliefs about their world. If so, the Matrix Hypothesis is not a skeptical hypothesis, and its possibility does not undercut everything that I think I know. (Chapter 5, p. 35)
Chalmers is suggesting that being in a simulation is not a situation in which we fail to know that the external world around us really exists. Suppose that we learn we are in a matrix. According to Chalmers, this fact tells us about the nature of the external world: it tells us that the physical world around us is ultimately made of bits, and that our creators were creatures who allowed our minds to interact with this world of bits. But upon reflection, knowing a new theory of the fundamental nature of the universe is just learning more physics. And while intriguing, this is not like proving that skepticism is true. For Chalmers contends that there is still a “physical world” which we interact with; what is different is that its fundamental physics is not about strings or particles, but bits. Furthermore, learning that there is a creator outside of
space and time who allowed our minds to interact with the physical world, while obviously of great metaphysical and personal import, is akin to learning that a particular religious view holds. This would be an earth shattering revelation, but it does not mean that we are not situated in the external world that we believe we are in.
Suggestively, a very basic brain in a vat was recently developed at the university of Florida in the laboratory of Thomas De Marse. It now is sophisticated enough to successfully fly a flight simulator.2 Bostrom would likely say that this is further proof that we are in a simulation; for when we start turning our own basic simulations on, this is, in effect, evidence that advancing societies have interest in doing so. It also indicates that we are nearing the point at which we are capable of surviving the technological age long enough to develop more advanced simulations. Indeed, I find De Marse’s development to be yet another telling example of the convergence between science fiction and science fact. Some of the most lavish science fiction thought experiments are no longer merely fictions - we see glimpses of them on the technological horizon.
