Adam Leite

In Knowledge and Its Limits, Timothy Williamson argues that knowledge is a purely mental state, that is, that it is never a complex state or condition comprising mental factors and non-mental, environmental factors. Three of his arguments are evaluated: arguments from (1) the non-analyzability of the concept of knowledge, (2) the “primeness” of knowledge, and (3) the (alleged) inability to satisfactorily specify the “internal” element involved in knowledge. None of these arguments succeeds. Moreover, consideration of the third argument points the way to a cogent argument that knowledge is not a purely mental state.

Modern-day heirs of the Cartesian revolution have been fascinated by the thought that one could utilize certain hypotheses – that one is dreaming, deceived by an evil demon, or a brain in a vat – to argue at one fell swoop that one does not know, is not justified in believing, or ought not believe most if not all of what one currently believes about the world. A good part of the interest and mystique of these discussions arises from the contention that the seeds of such arguments lie in our ordinary epistemic practices, so that external world skepticism can arise “from within”. But is this contention correct? I doubt it. Taking skepticism seriously requires that we address this question head on. To do so, I will approach skeptical arguments from a certain vantage point. I will try to stand, as far as possible, with both feet squarely in ordinary life. I will start out with all of our ordinary commitments about what is the case, about what we know or have reason to believe, about when someone knows, is justified, or has good reason to believe something, and about how one should proceed in deciding what to believe. My question, then, will be this. From within that vantage point can I somehow be moved in a reasonable way to accept the conclusion that I know far less about the world around me than I thought, or that epistemically speaking, I really ought not believe much of what I have believed about the world around me? In order for such movement to take place, I will have to find reason from within my ordinary standpoint to discount or reject much of what I ordinarily accept. And of course, that reason will have to come from some..

Traditional epistemological reflection on our beliefs about the world attempts to proceed without presupposing or ineliminably depending upon any claims about the world. It has been argued that epistemological externalism fails to engage in the right way with the motivations for this project. I argue, however, that epistemological externalism satisfyingly undermines this project. If we accept the thesis that certain conditions other than the truth of one's belief must obtain in the world outside of one's mind in order for one to have knowledge (or justified belief) about the world, then there is no good intellectual motivation for taking up the traditional project. This results stands even if we accept the traditional theses that knowledge requires justified belief and that justified belief requires the ability to provide good reasons for one's belief.

This book argues that external world skepticism is false for straightforward reasons. To make this case it develops and defends a neglected methodological approach involving a distinctive process of first-person reflection. We begin within the practices, procedures, and commitments of ordinary life and science. We then seek some reason to think skepticism true, carefully scrutinizing all the most important arguments. Finding no reason to think it true and decisive reasons to think it false, we reject it. As the book shows, this is a fully satisfactory refutation. No epistemological theorizing is needed. The book begins by exploring and defending this method in seminal works of G. E. Moore and J. L. Austin. Turning to contemporary epistemology, it asks why we shouldn't appeal to considerations about the world when responding to skeptical argumentation. No good reason is found, despite exploration of a wide range of central issues in recent epistemology. To the contrary, perfectly ordinary examples indicate that it is correct to reject the skeptical scenarios - the dreaming worry, Descartes' evil demon, the brain-in-a-vat - by appealing to things we know about the world. Likewise, considerations about sensory perception do not provide any reason to think our evidence excludes considerations about the world. Along the way, methodological lessons are drawn from consideration of the most important skeptical arguments in the contemporary literature. The book concludes by defending the satisfactoriness of its approach. What emerges is a new understanding of what philosophical illumination might look like in relation to core epistemological issues.

I take as my starting point the evident fact that people are capable of modifying their beliefs in response to reasons in the course of deliberation. This fact is sufficient to make notions such as responsibility, blameworthiness, and praiseworthiness applicable to people with regard to their beliefs. If a state is such, and one is such, that one is capable of determining it through one’s best evaluations of reasons in the course of deliberation, then even if it isn’t under one’s voluntary control, it is attributable to one as something for which one is appropriately held accountable. There is thus conceptual space for the possibility of one’s conducting oneself poorly or well with regard to it, and accordingly for the application of praise or criticism. And there is room for an evaluation of whether one has conducted oneself responsibly or irresponsibly – that is, whether one has proceeded in a way that takes proper account of the considerations which one reasonably could have been expected to take account of, or not.

My dissertation aims to understand external world skepticism and its place in our epistemic lives. I propose that the best way to investigate skepticism is to seek the strongest possible argument in its favor. In order to determine what requirements such an argument would have to meet, I develop and defend a novel contextualist account of empirical justification. This account involves four theses. In order to be justified in holding a belief, one must ordinarily be able to justify holding it, because epistemic basing relations depend upon the subject's justificatory activity. Justificatory status is relative to the real-world circumstances . The demand for a global justification of beliefs about the world is incoherent. Claims about the world can constitute fundamental justificatory starting-points in virtue of one's recognition that there is no reason to doubt them in one's circumstances. Taken together, I urge that being justified in holding an empirical belief is ordinarily a matter of being able to defend one's belief by appealing to other claims about the world which are adequate reasons for holding the belief in one's circumstances. I argue that a version of the skeptic's dream-argument goes through even if this account of empirical justification is correct. This argument is not generated by a closure principle, nor does it assume experiential foundationalism or any views in the philosophy of perception. I take this argument to be the strongest possible argument for skepticism. However, I maintain that it depends upon empirical considerations about the nature of dreams which we have good phenomenological and neurophysiological reasons for rejecting. I thus conclude that skepticism is an empirical issue and that we have good empirical reasons for rejecting the skeptic's claim. However, the fact that skepticism could be empirically true shows that the positive justificatory status of all of our empirical beliefs depends upon contingent facts. Our epistemic practices are vulnerable to empirical collapse, along with everything which depends upon them