Online research in philosophy

In discussions of perception and its relation to knowledge, it is common to distinguish what one comes to believe on the basis of perception from the distinctively perceptual basis of one's belief. The distinction can be drawn in terms of propositional contents: there are the contents that a perceiver comes to believe on the basis of her perception, on the one hand; and there are the contents properly attributed to perception itself, on the other. Consider the content.

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.

It is close to current orthodoxy that perceptual experience is to be characterized, at least in part, by its representational content, roughly, by the way it represents things as being in the world around the perceiver. Call this basic idea the content view (CV).

When philosophers speak of direct perceptual knowledge, they obviously mean to suggest that such knowledge is unmediated ? but unmediated by what? This is where we find evidence of violent disagreement. To clarify matters, I want to identify and briefly describe several important senses of "direct" that have helped shape our understanding of perceptual knowledge. They are (1) "Direct" as Non-Inferential Perception; (2) "Direct" as Unmediating by Objects of Perception; (3) "Direct" as Conceptually Unmediated Perception; (4) "Direct" as Independent Verification of Perceptual Beliefs; and (5) "Direct" as Perception of What is Epistemically Prior.

Paul Moser's book defends what has been an unfashionable view in recent epistemology: the foundationalist account of knowledge and justification. Since the time of Plato philosophers have wondered what exactly knowledge is. This book develops a new account of perceptual knowledge which specifies the exact sense in which knowledge has foundations. The author argues that experiential foundations are indeed essential to perceptual knowledge, and he explains what knowledge requires beyond justified true beliefs. In challenging prominent sceptical claims that we have no justified beliefs about the external world, the book outlines a theory of rational belief.

Bill Brewer presents an original view of the role of conscious experience in the acquisition of empirical knowledge. He argues that perceptual experiences must provide reasons for empirical beliefs if there are to be any determinate beliefs at all about particular objects in the world. This fresh approach to epistemology turns away from the search for necessary and sufficient conditions for knowledge and works instead from a theory of understanding in a particular area.

When philosophers speak of direct perceptual knowledge, they obviously mean to suggest that such knowledge is unmediated ? but unmediated by what? This is where we find evidence of violent disagreement. To clarify matters, I want to identify and briefly describe several important senses of "direct" that have helped shape our understanding of perceptual knowledge. They are (1) "Direct" as Non-Inferential Perception; (2) "Direct" as Unmediating by Objects of Perception; (3) "Direct" as Conceptually Unmediated Perception; (4) "Direct" as Independent Verification of Perceptual Beliefs; and (5) "Direct" as Perception of What is Epistemically Prior.

The notion of perceptual content is commonly introduced in the analysis of perception. It stems from an analogy between perception and propositional attitudes. Both kinds of mental states, it is thought, have conditions of satisfaction. I try to show that on the most plausible account of perceptual content, it does not determine the conditions under which perceptual experience is veridical. Moreover, perceptual content must be bipolar (capable of being correct and capable of being incorrect), whereas perception as a mental state is not (if it is veridical, it is essentially so). This has profound consequences for the epistemological view that perception is a source of knowledge. I sktech a two-level epistemology which is consistent with this view. I conclude that the analogy between perception and propositional attitudes, from which the notion of perceptual content is born, may be more misleading than it is usually thought.