This book is a defense of modal realism; the thesis that our world is but one of a plurality of worlds, and that the individuals that inhabit our world are only a few out of all the inhabitants of all the worlds. Lewis argues that the philosophical utility of modal realism is a good reason for believing that it is true.

The aim of this paper is to sketch a theory of justified belief. What I have in mind is an explanatory theory, one that explains in a general way why certain beliefs are counted as justified and others as unjustified. Unlike some traditional approaches, I do not try to prescribe standards for justification that differ from, or improve upon, our ordinary standards. I merely try to explicate the ordinary standards, which are, I believe, quite different from those of many classical, (...) e. g., ‘Cartesian’, accounts. (shrink)

In the movie, Memento, the hero, Leonard, suffers from a form of anterograde amnesia that results in an inability to lay down new memories. Nonetheless, he sets out on a quest to find his wife’s killer, aided by the use of notes, annotated polaroids, and (for the most important pieces of information obtained) body tattoos. Using these resources he attempts to build up a stock of new beliefs and to thus piece together the puzzle of his wife’s death. At one (...) point in the movie, a character exasperated by Leonard’s lack of biological recall, shouts. (shrink)

The Credit Theory of Knowledge (CTK)—as expressed by such figures as John Greco, Wayne Riggs, and Ernest Sosa—holds that knowing that p implies deserving epistemic credit for truly believing that p . Opponents have presented three sorts of counterexamples to CTK: S might know that p without deserving credit in cases of (1) innate knowledge (Lackey, Kvanvig); (2) testimonial knowledge (Lackey); or (3) perceptual knowledge (Pritchard). The arguments of Lackey, Kvanvig and Pritchard, however, are effective only in so far as (...) one is willing to accept a set of controversial background assumptions (for instance, that innate knowledge exists or that doxastic voluntarism is wrong). In this paper I mount a fourth argument against CTK, that doesn’t rest on any such controversial premise, and therefore should convince a much wider audience. In particular, I show that in cases of extended cognition (very broadly conceived), the most salient feature explaining S ’s believing the truth regarding p may well be external to S , that is, it might be a feature of S ’s (non-human, artifactual) environment. If so, the cognitive achievement of knowing that p is not (or only marginally) creditable to S , and hence, CTK is false. (shrink)

This paper explores the ramifications of the extended cognition thesis in the philosophy of mind for contemporary epistemology. In particular, it argues that all theories of knowledge need to accommodate the ability intuition that knowledge involves cognitive ability, but that once this requirement is understood correctly there is no reason why one could not have a conception of cognitive ability that was consistent with the extended cognition thesis. There is thus, surprisingly, a straightforward way of developing our current thinking about (...) knowledge such that it incorporates the extended cognition thesis. (shrink)

In Supersizing the Mind, Andy Clark argues that the human mind is not bound inside the head but extends into body and environment.

Where does the mind stop and the rest of the world begin? The question invites two standard replies. Some accept the demarcations of skin and skull, and say that what is outside the body is outside the mind. Others are impressed by arguments suggesting that the meaning of our words "just ain't in the head", and hold that this externalism about meaning carries over into an externalism about mind. We propose to pursue a third position. We advocate a very different (...) sort of externalism: an _active externalism_, based on the active role of the environment in driving cognitive processes. (shrink)

The place of social epistemology within contemporary philosophy, as well as its relation to other academic disciplines, is the topic of an ongoing debate. One camp within that debate holds that social epistemology should be pursued strictly from within the perspective of individualistic analytic epistemology. In contrast, a second camp holds that social epistemology is an interdisciplinary field that should be given priority over traditional analytic epistemology, with the specific aim of radically transforming the latter to fit the results and (...) methodology of the former. We are rather suspicious of this apparent tension, which we believe can be significantly mitigated by paying attention to certain recent advances within philosophy of mind and cognitive science. Accordingly, we attempt to explain how extended knowledge, the result of combining active externalism from contemporary philosophy of mind with contemporary epistemology, can offer an alternative conception of the future of social epistemology. (shrink)

We very often grant that a person can gain knowledge on the basis of epistemic artifacts such as telescopes, microscopes and so on. However, this intuition threatens to undermine virtue reliabilism according to which one knows that p if and only if one’s believing the truth that p is the product of a reliable cognitive belief-forming process; in an obvious sense epistemic artifacts are not parts of one’s overall cognitive system. This is so, unless the extended cognition hypothesis (HEC) is (...) true. According to HEC when parts of the environment become properly coupled to the agent’s brain then they too can be considered constitutive parts of the overall cognitive mechanism—i.e. cognition potentially extends to the world surrounding the agent. Interestingly, HEC and the broader framework of virtue reliabilism share some intriguing similarities, which render these two views mutually supportive. Making these similarities explicit provides a principled account of the way in which our knowledge-conducive cognitive characters may extend beyond our natural cognitive capacities by incorporating epistemic artifacts. (shrink)