A leading philosopher takes a mind-bending journey through virtual worlds, illuminating the nature of reality and our place within it. Virtual reality is genuine reality; that's the central thesis of Reality+. In a highly original work of "technophilosophy," David J. Chalmers gives a compelling analysis of our technological future. He argues that virtual worlds are not second-class worlds, and that we can live a meaningful life in virtual reality. We may even be in a virtual world already. Along the way, (...) Chalmers conducts a grand tour of big ideas in philosophy and science. He uses virtual reality technology to offer a new perspective on long-established philosophical questions. How do we know that there's an external world? Is there a god? What is the nature of reality? What's the relation between mind and body? How can we lead a good life? All of these questions are illuminated or transformed by Chalmers' mind-bending analysis. Studded with illustrations that bring philosophical issues to life, Reality+ is a major statement that will shape discussion of philosophy, science, and technology for years to come. (shrink)

Hilary Putnam’s BIV argument first occurred to him when ‘thinking about a theorem in modern logic, the “Skolem–Löwenheim Theorem”’ (Putnam 1981: 7). One of my aims in this paper is to explore the connection between the argument and the Theorem. But I also want to draw some further connections. In particular, I think that Putnam’s BIV argument provides us with an impressively versatile template for dealing with sceptical challenges. Indeed, this template allows us to unify some of Putnam’s most enduring (...) contributions to the realism/antirealism debate: his discussions of brains-in-vats, of Skolem’s Paradox, and of permutations. In all three cases, we have an argument which does not merely defeat the sceptic; it also shows us that we must reject some prima facie plausible philosophical picture. (shrink)

This paper argues that at least one of the following propositions is true: the human species is very likely to go extinct before reaching a "posthuman" stage; any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history ; we are almost certainly living in a computer simulation. It follows that the belief that there is a significant chance that we will one day become posthumans who run ancestor-simulations is false, unless we are currently (...) living in a simulation. A number of other consequences of this result are also discussed. (shrink)

This article reports on a newly discovered bug in the original simulation argument. Two different ways of patching the argument are proposed, each of which preserves the original conclusion.

Crispin Wright; IV*—On Putnam's Proof that We are not Brains-in-a-Vat1, Proceedings of the Aristotelian Society, Volume 92, Issue 1, 1 June 1992, Pages 67–94, h.

Hilary Putnam's argument against metaphysical realism (commonly referred to as the "model theoretic argument") has now enjoyed two decades of discussion.(1) The text is rich and contains variously construable arguments against variously construed philosophical positions. David Lewis isolated one argument and called it "Putnam's Paradox".(2) That argument is clear and concise; so is the paradoxical conclusion it purports to demonstrate; and so is Lewis' paradox-avoiding solution. His solution involves a position I call "anti-nominalism": not only are classes real, but they (...) are divided into arbitrary and 'natural' classes. The natural classes 'carve nature at the joints', being (as other philosophers might say) the extensions of 'real' properties, universals, or Forms.(3) Thus the argument was turned, in effect, into support for a metaphysical realism stronger than Putnam envisaged. (shrink)

Support is canvassed for a novel solution to the sceptical problem regarding our knowledge of the external world. Key to this solution is the claim that what initially looks like a single problem is in fact two logically distinct problems. In particular, there are two putative sceptical paradoxes in play here, which each trade on distinctive epistemological theses. It is argued that the ideal solution to radical scepticism would thus be a biscopic proposal—viz., a two-pronged, integrated, undercutting treatment of both (...) putative sceptical paradoxes. A particular biscopic proposal is then explored which brings together two apparently opposing anti-sceptical theses: he Wittgensteinian account of the structure of rational evaluation and epistemological disjunctivism. It is argued that each proposal enables us to gain a purchase on one, but only one, aspect of the two-sided sceptical problem. Furthermore, it is argued that these proposals are not only compatible positions, but also mutually supporting and advanced in the same undercutting spirit. A potential cure is thus offered for epistemic angst. (shrink)

Tim Button explores the relationship between words and world; between semantics and scepticism. -/- A certain kind of philosopher – the external realist – worries that appearances might be radically deceptive. For example, she allows that we might all be brains in vats, stimulated by an infernal machine. But anyone who entertains the possibility of radical deception must also entertain a further worry: that all of our thoughts are totally contentless. That worry is just incoherent. -/- We cannot, then, be (...) external realists, who worry about the possibility of radical deception. Equally, however, we cannot be internal realists, who reject all possibility of deception. We must position ourselves somewhere between internal realism and external realism, but we cannot hope to say exactly where. We must be realists, for what that is worth, and realists within limits. -/- In establishing these claims, The Limits of Realism critically explores and develops several themes from Hilary Putnam’s work: the model-theoretic arguments; the connection between truth and justification; the brain-in-vat argument; semantic externalism; and conceptual relativity. The book establishes the continued significance of these topics for all philosophers interested in mind, logic, language, or the possibility of metaphysics. (shrink)