Online research in philosophy

In this paper I discuss Fred Dretske's account of knowledge critically, and try to bring out how his account of informational content leads to cases of extreme epistemic good luck in his treatment of knowledge. My main interest, however, is to establish that the cases of epistemic luck arise because Dretske's account of knowledge in a fundamental way fails to take into account the role our actual recognitional capacities and powers of discrimination play in perceptually based knowledge. This result is, I believe, new. The paper has three sections. In Section 1 I give a short exposition of Dretske's theory, and make some necessary qualifications about how it is to be understood. In Section 2 I discuss in greater detail how the theory actually works, and provide some examples I think are very troublesome for Dretske. In Section 3 I argue that these cases establish my main claim. I also show that there are cases of epistemic bad luck due to Dretske's account of how information causes belief.

This book presents an attempt to develop a theory of knowledge and a philosophy of mind using ideas derived from the mathematical theory of communication developed by Claude Shannon. Information is seen as an objective commodity defined by the dependency relations between distinct events. Knowledge is then analyzed as information caused belief. Perception is the delivery of information in analog form (experience) for conceptual utilization by cognitive mechanisms. The final chapters attempt to develop a theory of meaning (or belief content) by viewing meaning as a certain kind of information-carrying role.

The question whether epistemological concepts are closed under deduction is an important one since many skeptical arguments depend on closure. Such skepticism can be avoided if closure is not true of knowledge (or justification). This response to skepticism is rejected by Peter Klein and others. Klein argues that closure is true, and that far from providing the skeptic with a powerful weapon for undermining our knowledge, it provides a tool for attacking the skeptic directly. This paper examines various arguments in favor of closure and Klein's attempted use of closure to refute skepticism. Such a refutation of skepticism is mistaken. But the closure principle is in any case false, so the skepticism that depends on it is undermined. The appeal of the closure principle derives from a failure to recognize an important feature of our epistemological concepts, namely, their context relativity.

In early essays and in more recent work, Fred Dretske argues against the closure of perception, perceptual knowledge, and knowledge itself. In this essay I review his case and suggest that, in a useful sense, perception is closed, and that, while perceptual knowledge is not closed under entailment, perceptually based knowledge is closed, and so is knowledge itself. On my approach, which emphasizes the safe indication account of knowledge, we can both perceive, and know, that sceptical scenarios (such as being a brain in a vat) do not hold.

Fred Dretske's "Knowledge and the Flow of Information" is an extended attempt to develop a philosophically useful theory of information. Dretske adapts central ideas from Shannon and Weaver's mathematical theory of communication, and applies them to some traditional problems in epistemology. In doing so, he succeeds in building for philosophers a much-needed bridge to important work in cognitive science. The pay-off for epistemologists is that Dretske promises a way out of a long-standing impasse -- the Gettier problem. He offers an alternative model of knowledge as information-based belief, which purports to avoid the problems justificatory accounts face. This essay looks closely at Dretske's theory. I argue that while the information-theoretic framework is attractive, it does not provide an adequate account of knowledge. And there seems to be no way of tightening the theory without introducing some version of a theory of justification -- the very notion Dretske's theory was designed to avoid.

Peter Baumann and Nicholas Shackel defend me against a serious criticism by Christoph Jäger. They argue that my account of information is consistent with my denial of closure for knowledge. Information isn’t closed under known entailment either. I think that, technically speaking, they are right. But the way they are right doesn’t help me much in my effort to answer the skeptic. I describe a way in which information, like knowledge, fails to be closed in a way that makes an information-based account of knowledge an effective tool in answering the skeptic.

Dretske proposes a theory of knowledge in terms of a theory of information, but wishes to deny that empirical knowledge settles the large question of scepticism. This leads him to deny the closure of knowledge under known entailment. In a recent paper Jäger argues that Dretske’s theory of information entails closure for knowledge, ‘at least for the kind of propositions here at issue’ (Jäger 2004:194). If Jäger is right, Dretske is seriously embarrassed and must give something up. In this paper I show that there are two flaws in Jäger’s argument. The principle of informational closure considered by Jäger is incompatible with Dretske’s theory of information, and Jäger’s argument that Dretske is committed to a certain kind of substitution instance of that principle of informational closure is invalid. I propose adequacy conditions on signalled information and use them to motivate a formulation of a general closure principle for signalled information. I show that Dretske’s account of information satisfies the adequacy conditions, but in a way which commits him to an instance of the general closure principle. I argue that Dretske is consequently committed to closure for some cases of knowledge for which he wishes to deny closure. Finally, I sketch how, on the basis of the closure principle to which Dretske is committed, Jäger’s broader argument may yet go through.

Christoph Jäger (2004) argues that Dretske’s information theory of knowledge raises a serious problem for his denial of closure of knowledge under known entailment: Information is closed under known entailment (even under entailment simpliciter); given that Dretske explains the concept of knowledge in terms of “information”, it is hard to stick with his denial of closure for knowledge. Thus, one of the two basic claims of Dretske would have to go. Since giving up the denial of closure would commit Dretske to skepticism, it would most probably be better to rather give up the information-theoretic account of knowledge. But that means that one of the best externalist views of knowledge has to be given up. I argue here that Jäger is mistaken and that there is no problem for Dretske. There is a rather easy way out of Jäger’s problem.