How is it possible ? Isn’t a simulated or “virtual” world necessarily a realm of illusion, and wouldn’t we be deceived if we took its inhabitants for real? Chalmers replies no, arguing that the labels “virtual” and “real” should not be opposed as implied by this objection. Admittedly, the products of a computer simulation are not part of physical reality, but there are other ways for something to be real. For example, consider the possibility of me throwing a World Series no-hitter, and then compare it to each of the following: my throwing a World Series no-hitter in the context of a simulated season in a video game, and my simply dreaming that I was throwing a no-hitter. There is a perfectly natural sense in which the middle possibility, where I play a simulated season without ever leaving my living room, is the one in which I really throw a no-hitter. (For example, if I brag about the achievement to my friends and they ask me if I really did, so I won’t lie to them or mislead them if I say yes, as long as it’s understood that we’re talking about a video game.) Chalmers applies a sophisticated version of this argument to the idea that our whole world is a massive simulation. Having discarded the error of confusing the real with the physical, we can see that there is nothing unreal about what happens in a virtual world.
But wait. For me to pitch a no-hitter in a World Series game, a lot of things would have to be true of me that aren’t – for example, that I had the ability to pitch effectively to professional hitters, and that at one point I was standing on the mound in a major league stadium. None of these things need to be true for me to throw a no-hitter only in a video game or only in a dream. Of course, those things wouldn’t have to be true either for me to throw a no-hitter in a massive computer simulation – in which case I myself wouldn’t have been a human being on a pitcher mound ( or in my living room or in bed), but a brain in a vat or a self-aware virtual avatar consisting only of digital bits. And doesn’t that show that there is an important difference in the way things go with me, and the nature of the activities in which I engage, depending on whether or not I am a living organism that acts in the physical world by means of my bodily movements? Doesn’t it reveal an important difference between, on the one hand, what we are and do in a physical world and, on the other hand, what we are and do in a purely virtual world?
This is a point where Chalmers’ argument rests on his attachment to a fundamentally Cartesian anthropology, and betrays his failure to recognize that the image of Descartes is at work in the background. Consider the following passage, in which Chalmers explains what makes a given body “mine”:
I might lose pain or hunger and be unable to eat or drink, but this body would still be my body. My thought might occur in a Cartesian mind, but that body would still be mine. And it is not so obvious that the physical body is the place of my existence. I could transplant my brain into a new body or upload myself to the cloud and exist without the old body. It can therefore be argued that, like my avatar [in a computer simulation]my physical body is not quite the same as me.
This argument is supposed to show that if I throw a pitch in a virtual baseball game, myself will be located on a pitcher’s mound no more and no less than if I do it in a physical game. According to Chalmers, what is true in both cases is that “my body”, whether a physical thing or a digital avatar, will be standing on a physical or virtual mound, and that my body will not be the same as me. This, of course, is exactly the conclusion of Descartes’ Second Meditation, argued in much the same way.
Beyond the similarity to Descartes’ arguments, it is striking that every description Chalmers gives of what “could” happen is entirely unchallenged and unsubstantiated. It is an observable fact that human beings can enter persistent vegetative states in which they lack consciousness and cannot eat or drink voluntarily. In contrast, the supposed possibility that human-like thought can occur in immaterial minds or be transplanted via our brains into new bodies or downloaded into computer systems is so far only a philosopher’s fantasy. And outside the confines of that fantasy, we have no way of telling what would happen if any of these “coulds” become real. Imagine that my brain is transplanted into another body, which then begins to think like me. What reason is there to think that the resulting person would actually be being me, rather than a mental duplicate of me would have emerged? The problem is even more serious in the case where “I” is supposed to have been uploaded to a digital cloud. Since multiple versions of “me” can be created simultaneously in this way, why should any of them claim to identify with the original? The answer, in each case, is that the only reason to say what Chalmers does is that we simply take Descartes’ mind picture for granted.
Reality+ is in many ways a resounding success. It’s well-written, cleverly illustrated, and packed with useful distinctions and powerful arguments. It makes excellent use of history and contemporary culture to help the general reader understand its key concepts. And he does all this without sacrificing any of the rigor one would expect in the treatment of these questions by an analytical philosopher in an academic journal.
Yet I also find the book to be a telling illustration of how one of the dominant contemporary approaches to philosophy may fall short of the demands of the discipline. So long as our philosophical thinking is tied only to fantasy or the furthest limits of scientific speculation, its conclusions will tend to reflect our casual and culturally contingent presuppositions. And as long as this work continues without being aware of the philosophical images on which our thinking is based, we will be unable to challenge the accuracy of these images or to seek potential alternatives to them.
Virtual worlds and the problems of philosophy
David J. Chalmers
$32.50 | 544 p.