The idea that knowledge can be extended by inference from what is known seems highly plausible. Yet, as shown by familiar preface paradox and lottery-type cases, the possibility of aggregating uncertainty casts doubt on its tenability. We show that these considerations go much further than previously recognized and significantly restrict the kinds of closure ordinary theories of knowledge can endorse. Meeting the challenge of uncertainty aggregation requires either the restriction of knowledge-extending inferences to single premises, or eliminating epistemic uncertainty in (...) known premises. The first strategy, while effective, retains little of the original idea—conclusions even of modus ponens inferences from known premises are not always known. We then look at the second strategy, inspecting the most elaborate and promising attempt to secure the epistemic role of basic inferences, namely Timothy Williamson’s safety theory of knowledge. We argue that while it indeed has the merit of allowing basic inferences such as modus ponens to extend knowledge, Williamson’s theory faces formidable difficulties. These difficulties, moreover, arise from the very feature responsible for its virtue- the infallibilism of knowledge. (shrink)
Harman and Lewis credit Kripke with having formulated a puzzle that seems to show that knowledge entails dogmatism. The puzzle is widely regarded as having been solved. In this paper we argue that this standard solution, in its various versions, addresses only a limited aspect of the puzzle and holds no promise of fully resolving it. Analyzing this failure and the proper rendering of the puzzle, it is suggested that it poses a significant challenge for the defense of epistemic closure.
Timothy Williamson has famously argued that the (KK) principle (roughly, that if one knows that p, then one knows that one knows that p) should be rejected. We analyze Williamson’s argument and show that its key premise is ambiguous, and that when it is properly stated this premise no longer supports the argument against (KK). After canvassing possible objections to our argument, we reflect upon some conclusions that suggest significant epistemological ramifications pertaining to the acquisition of knowledge from prior knowledge (...) by deduction. (shrink)
In the Alcibiades I, Socrates argues for the importance of self-knowledge. Recent interpreters contend that the self-knowledge at issue here is knowledge of an impersonal and purely rational self. I argue against this interpretation and advance an alternative. First, the passages proponents of this interpretation cite—Socrates’ argument that the self is the soul, and his suggestion that Alcibiades seek self-knowledge by looking for his soul’s reflection in the soul of another—do not unambiguously support their reading. Moreover, other passages, particularly Socrates’ (...) cross-examination of Alcibiades, suggest the contrary reading, that self-knowledge includes knowledge of qualities peculiar to the individual. (shrink)
According to many scientists and futurists, technological advancements may soon make it possible significantly to extend average human life expectancy. This is often called "superlongevity." I discuss two arguments against superlongevity-first, a utilitarian argument from Peter Singer, and then an argument of my own. Although neither argument is decisive, I conclude that there are serious concerns about whether superlongevity would be a good idea that we need to reflect on as we consider the possibility.
Slip modes in single crystals of mercury deformed in tension at ?70°c and at ?183°c were determined experimentally, using conventional techniques of slip line observation and x-ray diffraction. At both temperatures the slip plane was , where indices are given with respect to the facecentred rhombohedral cell. At ?70°c some crystals slipped in the direction and the remainder in the direction. For both these modes the mean critical resolved shear stress was 16±5 g mm?2. At ?183°c some crystals slipped in (...) the direction with a critical resolved shear stress of 50±17 g mm?2; the remainder, which in the light of the behaviour at ?70°c would have been expected to slip in , deformed by twinning without prior slip. The interatomic spacing along is 15% greater than that along , the closest-packed direction; the predominance of as a slip direction is therefore surprising. (shrink)
There is strong sentiment for a policy which would exclude foreigners from access to organs from American cadaver donors. One common argument is that foreigners are free riders; since they are not members of the community whichgives organs, it would be unfair to allow them toreceive such a scarce resource.This essay examines the philosophical basis for the free rider argument, and compares that with the empirical data about organ donation in the U.S. The free rider argument ought not (...) to be used to exclude foreign nationals because it is based on fallacious assumptions about group membership, and how the giving community is defined. Polls show that even among the seventy-five per cent of Americans who support organ donation, only seventeen per cent had taken the small step of filling out donor cards. Therefore, it goes against logic to define the giving community as coextensive with American residency, while excluding foreigners who might well have become donors had they lived in countries which provided that option. (shrink)
Cet essai se concentre sur les tentatives de Hare de résoudre le problème du profiteur (free-rider) dans les termes de la théorie oú il distingue les niveaux intuitif et critique de la pensée morale. Hare fait valoir que la pensée critique correcte en utilitarisme des actes endosse les régles qui serviront a la pensée intuitive, règles enjoignant à un individu de s’acquitter de ses responabilités sociales, par exemplevoter ou recycler ses ordures. Je lais valoir que Hare propose ou suggère (...) implicitement divers critères de sélection des règles, critères que j’entreprends de désambiguïser. Je soutiens en outre qu’aucun de ces critères n’arrive à rèsoudre complètement le problème du profiteur. (shrink)
In this essay, I argue that environmental risk is a strategic situation that places the individual citizen in the position of an imprisoned rider who is being exploited without his or her knowledge by the preferences of others. I contend that what is at stake in policy decisions regarding environmental risk is not numerical probabilities or consistent, complete, transitive preferences for individual welfare, but rather respect for the human agency of the individual. Human agency is a prerequisite to one’s (...) utility function and is threatened and exploited in the strategic situation that produces the imprisoned rider. This problem is created by the policy maker’s assumption that his or her task is to assume rational preferences and aggregate them. The guidelines for evaluation and justification of policy should move beyondwelfare preferences and involve an active state protecting human agency and empowering the imprisoned rider. Only in this way can we free all citizens (a priori) from fear of exploitation by those who would impose collective and irreversible risk on each of them in violation of their unconditional right to their own agency. (shrink)
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In this book review, I assess the merits of the book as a whole (it's good!) while focusing in particular on chapters by Claudia Card, Patrick Frierson, Robert Louden, Pablo Muchnik, Jeanine Grenberg, and Allen Wood.
Lloyd's book, Morality in the Philosophy of Thomas Hobbes , correctly stresses the deductive element in Hobbes's proofs of the laws of nature. She believes that “the principle of reciprocity” is the key to these proofs. This principle is effective in getting ego-centric people to recognize moral laws and their moral obligations. However, it is not, I argue, the basic principle Hobbes uses to derive the laws of nature, from definitions. The principle of reason, which dictates that all similar cases (...) be treated similarly, is. It is important not to diminish the centrality of reason for Hobbes because it is essential to understanding his reply to “the fool” and understanding why the state of nature cannot be a continuum. (shrink)
The question of personal identity—what makes a person the same person over time—is puzzling. Through the course of a life, someone might undergo a dramatic alteration in personality, radically change her values, lose almost all of her memories, and undergo significant changes in her physical appearance. Given all of these potential changes, why should we be inclined to regard her as the same person? Battlestar Galactica presents us with an even bigger puzzle: What makes a Cylon the same Cylon over (...) time? There are only twelve different models, but there are many copies of each. So what makes the resurrected Caprica Six the same Cylon as the one who seduced Gaius Baltar into betraying humanity, and yet a different Cylon from the tortured Gina or Shelly Godfrey? (shrink)