David J. Chalmers

There’s an idea, discussed widely these days, that what we call “the universe” may be a simulation running on a gigantic computer: the Simulation Hypothesis. Now, if you like you can simply take this literally (as Hollywood has done), but for me its real interest is that it provides a fresh new way of looking at stale, often millennia-old, questions. For example, back in the 17th Century René Descartes was asking: how can I know that anything outside my own head is real? What if I’m show more dreaming all this, or some evil demon is deceiving me into thinking there’s a world out there when there isn’t? Were he alive today in the computer age, Descartes’ question would be more along the lines of: how can I know that I’m not in some kind of simulation?
    David Chalmers’ Reality+ explores this new angle on philosophy. It covers: the nature of knowledge (i. e. how we know about the outside world) and how far we can trust that knowledge; the nature of the world (or universe) we are looking at; the nature of the instrument (mind) doing the looking; God (as creator of that universe, and possible nature of); value (what is “good”, what is “right”)…all squinted at through the newfangled lens of the Simulation Hypothesis. In addition, there’s something even newer too—virtual reality—and, while still unwieldy at present (headset, gloves and so on), it’s certain to become ever more subtle and invasive. Much of this book is about VR and what it may already be telling us about the relationship between mind and world. Running through it is what Chalmers calls “Simulation realism”, his contention that virtual objects are real—i.e. things which are part of a virtual world are real in the fullest sense of that word; and that if something (or someone) is part of a simulation, that doesn’t make it (or them) any less real.
    Chalmers, a philosopher himself, makes his case very well, and one particular chapter out of the book’s twenty-four contained an idea so striking I’ve been mulling it over myself ever since. As for the Simulation Hypothesis itself though, I’m not, so far, persuaded by that. But it is like opening a window and letting some fresh clean air into the musty atmosphere of a philosophy class; and what’s also obvious to me is that, as we begin to design and run simulated universes ourselves, it’s going to let in a whole lot more. show less

I've asserted for a long time that reality is overrated, and that we'd be better off if we uploaded ourselves to a virtual world. This fantastic and fascinating book examines the philosophical issues related to both of these concepts.
Along the way, it tackles everything from the trolley problem to brains in vats, and addresses a wide range of concepts and ideas.

Although by no means light reading, it's written clearly, and all of the philosophical jargon is defined as it's used, so you can show more still easily understand everything even if you don't remember off the top of your head the difference between ontology and deontology, or don't know Kant's categorical imperative from epistemic structuralism.
Chalmers is also careful to differentiate between his descriptions of others' works and his own opinions, which I appreciated.

Not everyone may agree with all of his conclusions regarding whether or not we may be living in a computer simulation and how we can tell, but if you ever wondered things like "how do I know what is real," whether it's morally acceptable to commit crimes in video games, how to organize society in the metaverse, questioned the personhood status of artificial people like Star Trek's Commander Data, or were intrigued by The Matrix films or enjoyed Black Mirror, then you will find this book interesting, and [unless you are a philosophy major] likely learn a lot of philosophy along the way. show less

The simulation hypothesis states that, as civilizations advance, they develop the capability to simulate entire worlds, and once they do, they will create hundreds or even thousands of them. With hundreds or thousands of simulations running, the number of individuals within simulations will far outnumber non-simulated individuals in the universe. And if that’s the case, then it’s more likely that you exist within a simulation than in a non-simulated world. Therefore, it’s reasonable show more for you to believe that this has already happened, and that you currently inhabit a simulation.

Some people, like David Chalmers, believe that this argument should be taken seriously. While Chalmers doesn’t claim to know we are living in a simulation, he does think it’s a serious possibility, enough so to write an entire book about the prospect and what it means for the future of our VR and augmented reality technologies.

I, for one, do not find the simulation hypothesis to be persuasive. While I might ultimately be living in a simulation, and I can’t prove that I’m not, this is not the same thing as making the claim that it is reasonable for me to suppose that I am, especially without any convincing evidence.

Chalmer's argument makes a few critical mistakes: (1) it inappropriately shifts the burden of proof, (2) it incorrectly assumes that knowledge requires certainty, and (3) it seriously underestimates the difficulty involved in creating simulations of entire worlds with conscious inhabitants.

Chalmers makes all of these mistakes in his latest book, Reality : Virtual Worlds and the Problems of Philosophy. The problem for the reader is, if you don’t find the simulation hypothesis to be persuasive, you’re not going to find the rest of the book to be very persuasive (or, at times, very interesting) either. If you do find the simulation hypothesis to be persuasive, however, you will learn more about its implications than you ever could have imagined.

Despite disagreeing with Chalmers, I did find his arguments to be well presented and thought-provoking nonetheless. Chalmers uses the simulation hypothesis—along with VR technology—to introduce the full spectrum of philosophical problems ranging from the nature of reality, knowledge, and values to the deepest questions we can ask about the mind, language, science, religion, and politics. It’s a fascinating journey and an interesting spin on the problems of philosophy, but in the end, in my mind, it’s an ultimately misguided one. show less

(Original Review, 2010-10-30)

Is the assumption that brains are "just magic" - unlike kidneys or spleens or bones correct? This elevation of "consciousness" to an almost dualistic status is irritating beyond belief, and seems to stem (pardon the pun) from the fact that brains are hellishly complicated and difficult to measure (difficult, but becoming easier).

Philosophers have proven USELESS at answering questions, but particularly useFUL at asking the wrong ones. We never did get a straight show more answer as to how many angels could dance on the point of a needle (or head of a pin depending on your source, it matters not). If I have learnt anything from my experience as a scientist, it is that sometimes, if you ask a stupid question, you get a stupid answer, and so continuing to ask the stupid question in the hope that the answer will become sensible is actually not very bright. "What is it like to be a bat?" Hmm, not sure. What's it like to be another human being? Since our brains - and more to the point our entire nervous systems - wire themselves uniquely, it would be hard to tell. This is the scientific equivalent of Bilbo's challenge to Gollum in The Hobbit: "What have I got in my pocket?" It's a stupid question, no matter how interesting the answer might be. Actually, since there are some blind humans who have learnt to echo-locate [2018 EDIT: And when, inevitably, technology brings us "Google Sonic Glasses" that connect directly to the brain, we can partly answer the question.]

Our brains are built to simulate an approximation of the world, because in being able to predict the world, our survival is more likely. It stands to reason that if we have a visual sense to detect objects, then part of that simulation will be what we refer to as sight, and if it updates in near real-time then it will immediately become "an experience". Add to that mix the multiple streams of information being centrally routed, and an algorithm to pick the important ones to respond to - thus leading to an ever-shifting spotlight of attention - and we understand broadly why we experience what we do and how. “The Hard Problem” is just another name for dualism or animism or vitalism or what I scathingly refer to as "Magic Pixies", a desire to make humans supernatural, rather than see us as what we are: complex, adaptive, resourceful.

There are good evolutionary reasons why sensation would be referred to a point, a locus of interaction with the world. There are good reasons for extrapolating behaviour into the future, rather than simply reacting to sensation. I would not be surprised for the interaction of sensation and extrapolation, memory, reflex and learning to coalesce in a sense of self: it is important to recognise the difference of self and non-self, and we know that the distinction can be impaired in illness and in illusions. There isn't one hard problem, there is consciousness emerging from individually soluble neurophysiological problems.

I suspect the question of why we're not "just brilliant robots, capable of retaining information, of responding to noises and smells and hot saucepans, but dark inside, lacking an inner life?" should be turned around. Man-made computers are becoming more sophisticated all the time, and it is probably only a matter of time before computers/robots can think and feel like us, or, indeed, in ways vastly superior to us. This theme is already completely out there (and has been for decades) in the world of science fiction.

We are clearly still a long way from answering all the "easy questions" (a few of which are cited in Chalmer's book) that are pertinent to the human brain, and I don't know how hard it would be to make a computer that modelled the thought processes of a human brain (perhaps partly because current computers use basic mechanisms such as logic gates that have somewhat different physical properties to those of neurons and synapses etc.). However, if these two things could be done (and they can both be classed as "easy questions" in the terms of Chalmer's take), we would, I am sure, have made a conscious machine reassembling a human brain, and the so called "hard question" of the basis of consciousness would simply disappear. Artificial consciousness simply depends on a level of complexity which man-made computers have yet to reach. Consciousness is surely dependent on biological entities for its origin, but not necessarily for its continuation. I know this Singularity stuff is quite hip, and popular in some circles, it strikes me as complete nonsense. Computers don't feel. Current "AI" can accomplish some tasks now that are really easy to humans, but they don't do it in the same way as us, and even where it "learns" it simply runs a series of calculations. Even if future AI could seems to us to be conscious, it will still be a simulacrum, just a really good one. It won't be alive and it won't be self-aware. I think the whole concept of The Singularity is based upon the premise that sufficiently complex technology is indistinguishable from magic to most people. But that is a failure of individuals to grasp its complexity, not that there is really "magic" going on… show less