The principle of epistemic closure is the claim that what is known to follow from knowledge is known to be true. This intuitively plausible idea is endorsed by a vast majority of knowledge theorists. There are significant problems, however, that have to be addressed if epistemic closure – closed knowledge – is endorsed. The present essay locates the problem for closed knowledge in the separation it imposes between knowledge and evidence. Although it might appear that all that stands between knowing (...) the truth of the premises of a valid inference and knowledge of its conclusion is inferring it from the premises, the evidence for each of the premises may jointly count against the conclusion. The intuitive view regarding inferred knowledge says one thing, the evidence says another. One epistemological framework that seems to have the resources to resolve this tension endorses the view that knowledge always requires conclusive evidence. A second framework resolves the tension by limiting the scope of the closure principle. Only inferences drawn directly from propositions contained in the scope of a single knowledge operator are considered closed. The aim of the present essay is to revive the unpopular third option, the idea that knowledge is open. The essay proceeds by arguing that in different ways the two former frameworks only succeed in relocating the problem, not in resolving it. The first framework, the infallibilist view, relocates the problem to a sharp separation between knowledge of the occurrences of events from knowledge of their chance of occurring, a separation leading to several significant additional problems. The fallibilist view, the second framework, in endorsing closure neglects to take into full account the ways in which evidence fails to be transitive. For instance, evidence can count in favor of a conjunction while counting against each of its conjuncts. This fact, which is argued for in the essay on probabilistic as well as non-probabilistic grounds, is used as the foundation of an argument against closed knowledge that can be used as a way to understand several of the most fundamental challenges of epistemology. Not only can an open knowledge view that is based on open evidence resolve all these problems in a simple and natural way, it can also respond to formidable challenges that significantly hinder other open knowledge views. There are good reasons, then, to view both knowledge and evidence as open. (shrink)

Many philosophers and scientists rightly take hallucinations to be phenomena that challenge in a most pressing way our theories of perception and cognition, and epistemology in general. However, very few challenge the received views on the hallucinatory experience and even fewer critically delve into the subject with both breadth and depth. There are all kinds of problems concerning hallucinations—including conceptual, methodological, and empirical issues—that call for a multilevel analysis and an interdisciplinary approach which in turn provide the detail and scope (...) that the subject demands. In this paper, I present and briefly discuss four interrelated problems: (1) definitions, (2) dependence on perception, (3) two views on hallucinations, and (4) methodology. Neglect or underestimation of these problems, among other things, continue to prevent a proper understanding of the concept and the corresponding experience, giving rise to misconceptions and even plain myths on the subject. Hallucinations do occur; but in order to productively investigate them (for whatever end), we first need to get clear on the concept and develop a suitable epistemological framework for their analysis. (shrink)

“Naturalization” is the game in town in the science of mind and consciousness. How is it possible to give a naturalistic account of consciousness without simply denying its phenomenal, experiential and intentional component? I address this question by examining Dretske’s representationalist theses, showing that their main defect is the absence of any characterization of the structure of intentional/representational states, be it perception (presentation) or intuitive presentification. I conclude these considerations by indicating a series of difficulties a programme of “naturalizing” consciousness (...) has to confront when taking seriously what is shown by phenomenological analyses of consciousness and intentionality. (shrink)