The guiding questions of this volume are: Can we have knowledge of the external world of things outside our minds?

Knowledge and its Limits presents a systematic new conception of knowledge as a kind of mental stage sensitive to the knower's environment. It makes a major contribution to the debate between externalist and internalist philosophies of mind, and breaks radically with the epistemological tradition of analyzing knowledge in terms of true belief. The theory casts new light on such philosophical problems as scepticism, evidence, probability and assertion, realism and anti-realism, and the limits of what can be known. The arguments are (...) illustrated by rigorous models based on epistemic logic and probability theory. The result is a new way of doing epistemology and a notable contribution to the philosophy of mind. (shrink)

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.

The course of my experience is quite consistent with the hypothesis that it is being produced by a mad scientist who is feeding into my sensory receptors entirely delusive stimuli. Indeed, I could at this very moment be nothing more than a brain floating in a vat of nutrients, my nerve ends linked up to some infernal apparatus by means of which my unknown deceiver induces in me utterly erroneous beliefs about the world.So begins a familiar line of thought which (...) dramatizes an equally familiar sceptical problem about the relation between our experiences and the world. However, Hilary Putnam has recently offered a marvellously ambitious argument which is intended to kill stone-dead the philosophical fantasy that we might be deluded brains in a vat. (shrink)

The course of my experience is quite consistent with the hypothesis that it is being produced by a mad scientist who is feeding into my sensory receptors entirely delusive stimuli. Indeed, I could at this very moment be nothing more than a brain floating in a vat of nutrients, my nerve ends linked up to some infernal apparatus by means of which my unknown deceiver induces in me utterly erroneous beliefs about the world.So begins a familiar line of thought which (...) dramatizes an equally familiar sceptical problem about the relation between our experiences and the world. However, Hilary Putnam has recently offered a marvellously ambitious argument which is intended to kill stone-dead the philosophical fantasy that we might be deluded brains in a vat. (shrink)

UNCLEAR as it is, the traditional doctrine that the notion "meaning" possesses the extension/intension ambiguity has certain typical consequences. The doctrine that the meaning of a term is a concept carried the implication that mean- ings are mental entities. Frege, however, rebelled against this "psy- chologism." Feeling that meanings are public property-that the same meaning can be "grasped" by more than one person and by persons at different times-he identified concepts (and hence "intensions" or meanings) with abstract entities rather than (...) mental entities. However, "grasping" these abstract entities was still an individual psychological act. None of these philosophers doubted that understanding a word (knowing its intension) was just a matter of being in a certain psychological state (somewhat in the way in which knowing how to factor numbers in one's head is just a mat- ter of being in a certain very complex psychological state). (shrink)

Consider the skeptic about the external world. Let’s straightaway concede to such a skeptic that perception gives us no conclusive or certain knowledge about our surroundings. Our perceptual justification for beliefs about our surroundings is always defeasible—there are always possible improvements in our epistemic state which would no longer support those beliefs. Let’s also concede to the skeptic that it’s metaphysically possible for us to have all the experiences we’re now having while all those experiences are false. Some philosophers dispute (...) this, but I do not. The skeptic I want to consider goes beyond these familiar points to the much more radical conclusion that our perceptual experiences can’t give us any knowledge or even justification for believing that our surroundings are one way rather than another. (shrink)

This essay is concerned with solipsism, understood as the extreme sceptical view that I have no knowledge except of my subjective state. A less rough formulation of the view is mooted, inspired by a Quinean combination of naturalism and empiricism. An objection to the resultant position is then considered, based on Putnam’s argument that we are not brains in vats. This objection is first outlined, then pitted against a series of counter-objections. Eventually it is endorsed, but only at the price (...) of exposing the formulation of solipsism in question as not, after all, a satisfactory formulation. This leads to further speculation about the status of solipsism itself. Two of the possibilities that are considered are, firstly, that it is incoherent and, secondly, that it is inexpressible. (shrink)

Hilary Putnam has offered two arguments to show that we cannotbe brains in a vat, and one to show that our cognitive situationcannot be fully analogous to that of brains in a vat. The latterand one of the former are irreparably flawed by misapplicationsof, or mistaken inferences from, his semantic externalism; thethird yields only a simple logical truth. The metaphysical realismthat is Putnam’s ultimate target is perfectly consistent withsemantic externalism.

This work, written from a neo-Pyrrhonian perspective, is an examination of contemporary theories of knowledge and justification. It takes ideas primarily found in Sextus Empiricus's Outlines of Pyrrhonism, restates them in a modern idiom, and then asks whether any contemporary theory of knowledge meets the challenges they raise. The first part, entitled "Gettier and the Problem of Knowledge," attempts to rescue our ordinary concept of knowledge from those philosophers who have assigned burdens to it that it cannot bear. Properly understood, (...) Fogelin shows that the concept of knowledge is unproblematic. The second part of this study, called "Agrippa and the Problem of Justification," examines Agrippa's contribution to Pyrrhonism, a systematic reduction of its procedures which came to be known as the "Five Modes Leading to the Suspension of Belief." These modes present a completely general procedure for refuting any claim a dogmatist might make. Though largely unnoticed, there is, according to Fogelin, an uncanny resemblance between problems posed by Agrippa's "Five Modes" and those that contemporary epistemologists address under the heading of a theory of justification. Fogelin examines the strongest contemporary theories of justification--in both foundationalist and anti-foundationalist forms. The conclusion is that recent philosophical writings on justification have made no significant progress in responding to the Pyrrhonian problems these writings have addressed. (shrink)

This paper defends the legitimacy of semantical responses to certain skeptical challenges, with a particular focus on Putnam’s treatment of a particular version of Brain-in-Vat skepticism. It argues that while Putnam’s argument does not provide a general reply to Brain-in-Vat skepticism, the general approach it exemplifies is actually crucial in replying to other skeptical challenges that are otherwise hard to rebut.

The sceptic about the external world presents us with a paradox: an apparently acceptable argument for an apparently unacceptable conclusion—that we do not know anything about the external world. Some paradoxes, for instance the liar and the sorites, are very hard. The defense of a purported solution to either of these two inevitably deploys the latest in high-tech philosophical weaponry. On the other hand, some paradoxes are not at all hard, and may be resolved without much fuss. They do not (...) contain profound lessons about the human condition. Where should we place the sceptical paradoxes? (shrink)

This is a response to a recent Philosophical Studies article by Bredo Johnsen, in which he makes a number of criticisms of Putnamian anti-skeptical arguments.

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)

The following is not a successful skeptical scenario: you think you know you have hands, but maybe you don't! Why is that a failure, when it's far more likely than, say, the evil genius hypothesis? That's the question.<br><br>This is an earlier draft.