Human beings who have mastered a natural language are self-conscious creatures: they can think, and indeed speak, about themselves in the first person. This dissertation is about the significance of this capacity: what it is and what difference it makes to our minds. My thesis is that the capacity for self-consciousness is essential to rationality, the thing that sets the minds of rational creatures apart from those of mere brutes. This, I argue, is what Kant was getting at in a famous passage of his Critique of Pure Reason, when he claimed that a representation which could not be "accompanied with the 'I think'" would be "nothing to me" as a thinking being. I call this claim the Kantian thesis. My dissertation seeks to explain and defend the Kantian thesis, to show how it entails that the advent of self-consciousness brings with it a new kind of mind, and to sketch the implications of this point for a philosophy of mind that seeks to understand the minds of rational creatures. This involves, on the one hand, an investigation of the kinds of capacities that characterize a rational creature, and, on the other hand, an argument connecting reason with self-consciousness. I show that a rational creature, in the interesting sense, is one capable of conceptual representation, and I argue that (1) to represent conceptually is to represent in a way that decouples information from any particular context or purpose, (2) this special form of representation is possible only in a creature that can reflect explicitly on grounds for judging a proposition true, and (3) to have this capacity to reflect explicitly on grounds is necessarily to have the crux of self-consciousness. If this is right, then the representations of a rational creature must differ from those of a nonrational creature not merely in complexity but in kind. The dissertation sketches the implications of this point for various forms of naturalism and reductionism in the philosophy of mind, for debates about how to explain "first person authority," and for our understanding of the sort of failure of self-consciousness involved in self-deception.

How can perception yield knowledge of the world? One challenge in answering this question is that one necessarily perceives from a particular location. Thus, what is immediately perceptually available is subject to situational features, such as lighting conditions and ones location. Nonetheless, one can perceive the shape and color of objects. My dissertation aims to provide an explanation for how this is possible. The main thesis is that giving such an explanation requires abandoning the traditional model of perception as a two-place relation between subjects and objects in favor of a model of perception as a three-place relation between subjects, objects, and situations. In a first part, I show that treating perception as a three-place relation allows one to embrace the motivations for phenomenalism and indirect realism by recognizing that objects are presented a certain way, while preserving the intuition that subjects directly perceive objects. Second, it allows one to acknowledge that perceptions are not just individuated by the objects they are of, but by the way those objects are presented given the situational features. In a second part, I spell out the consequences of the situation-dependency of perception for perceptual content. I argue that a view on which perception represents objects is compatible with the idea that perception is a matter of standing in relation to objects, if perceptual content is understood in terms of potentially gappy content schema. If one acknowledges that perception is both relational and representational, the problems of pure relationalist and pure intentionalist accounts can be avoided. In contrast to pure relationalism, such a view explains how veridical and hallucinatory experiences can be phenomenologically indistinguishable. Both experiences share a common content schema. But in contrast to pure intentionalism, the view explains how the content of these experiences differ. In the case of a veridical experience, the content schema is saturated by an object. In a hallucination, the content schema is gappy. My dissertation explores the implications of these ideas for the particularity of perception and the relation between perceptual consciousness, content, and attention.

It is now commonly accepted that any adequate history of late nineteenth and early twentieth century philosophy - and thus of the origins of analytic philosophy - must take seriously the role of Neo-Kantianism and Kant interpretation in the period. My dissertation is a contribution to our understanding of this interesting but poorly understood stage in the history of philosophy. Kant's theory of the concepts, postulates, and proofs of geometry was informed by philosophical reflection on diagram-based geometry in the Greek synthetic tradition. However, even before the widespread acceptance of non-Euclidean geometry, the projective revolution in nineteenth century geometry eliminated diagrams from proofs and introduced "ideal" elements that could not be given a straightforward interpretation in empirical space. A Kantian like the very early Russell felt forced to regard the ideal elements as convenient fictions. The Marburg Neo-Kantians—the philosophical school that included Ernst Cassirer (1874-1945)—thought that philosophy, as "transcendental logic," needed to take the results of established pure mathematics as a "fact," not a fiction. Cassirer therefore updates Kant by rejecting the "Transcendental Aesthetic" and by using elements in Richard Dedekind's foundations of arithmetic to rework Kant's idea that the geometrical method is the "construction of concepts". He further argues that geometry is "synthetic" because it progresses when mathematicians introduce new structures (like the complex projective plane) that are not contained in the old structures, but unify them under a new point-of-view. This new "Kantian" theory of modern mathematics, Cassirer argues, is inconsistent with the traditional theory of concept formation by abstraction. Drawing on earlier Neo-Kantian interpretations, Cassirer argues that Kant's theory of concepts as rules undermines the traditional theory of concept formation and gives a "transcendental" defense of the new logic of Frege and Russell. (In an appendix, I discuss the contemporaneous accounts of concept formation in Gottlob Frege and Hermann Lotze.)

I explore and defend the distinction between an abstract concept and conceptions of that concept—different ways of explicating the content of that concept. In particular, I investigate contested concepts: concepts for which there appear to be genuine, principled disputes about which of several competing conceptions is the correct one. Although philosophers (e.g., John Rawls and Ronald Dworkin) and others often employ the concept/conception distinction, it has seldom been the subject of sustained philosophical inquiry. In particular, little attention has been paid to its consequences for philosophy of language and philosophy of mind. This is unfortunate, for if they are adequately to explain certain common and important features of language and thought, theories of content must find a place for the concept/conception framework. I begin with a presentation of some examples of contested concepts, and then offer four conditions that jointly specify contested concepts and articulate four desiderata for an account of contested concepts. Next, I assess work in this area by W.B. Gallie, Christopher Peacocke, and James Higginbotham, and briefly consider the ramifications of the concept/conception framework for any general account of concepts. After presenting a hypothetical example of an extended conceptual contest, surveying the features of such disputes, I argue that the contested concept phenomenon is theoretically novel with respect to theories of content, in the sense that it resists assimilation to similar, familiar phenomena (e.g., ambiguity, vagueness, or confusion). Finally, I develop a positive account of contested concepts, arguing that when we attend to the considerations that exert rational force in disputes over contested concepts, we see that the contents of such concepts are intimately connected with the notion of reflective equilibrium. I close with a brief survey of some areas for future research and applications.

The topic of my dissertation is selfhood. I aim to explain what a self is such that it can sometimes succeed and other times fail at thinking and acting autonomously. I open by considering a failure of autonomy to which I return throughout the dissertation. The failure is that of self-deception. I show that in common cases of self-deception the self-deceived individual fails, due to a motive on his part, to be able to explain the cause of some belief or action of his. There are several philosophical projects that arise when one reflects on this failure. They are presented by the following questions: what are our minds like, such that this failure is possible? For what should we criticize the self-deceived individual, given that he has a motivated lack of self-knowledge but does not know he is so motivated? Is the self-deceived individual epistemically criticizable for lacking explanatory self-knowledge in a way that he is not criticizable for lacking knowledge that would help him explain anothers thoughts and actions? By answering these questions I provide an account of the rational unity that goes missing in self-deception and in the related phenomenon of epistemic akrasia. This unity canand I argue, shouldbe present in bodily action as well. When a person acts without this unity, he acts in a weak-willed, akratic way. I provide an account of this disunity, which, when added to my account of the disunity of self-deception, reveals the rational unity of an autonomous agent, the rational unity of the self.

The goal of my dissertation is to give an account of our capacity for a priori knowledge in terms of fundamental features of conceptual thought. In a nutshell, the claim is that a priori knowledge is possible because thinkers are able to recognize the norms that their thinking is subject to. But, as I argue, the contents of our propositional attitudes are themselves individuated in terms of the norms that fix their place in our thinking. Since contents — Fregean thoughts — are what may be the case, it follows that knowledge of the norms of thinking can be substantive knowledge of the possible shapes reality can take.

The philosophy of action defines itself by reference to a pair of canonical divisions. First, among events, a distinction is drawn between that which is a "mere event" and that which is an "action." Then, a second distinction is drawn among actions, between that which is action in some qualified way---because it is unintentional, or unconscious, or unfree, or what have you---and that which is action unqualifiedly. "The standard approach," as Anscombe called it, is to take for granted the genus EVENT, and to hunt for the differentia of action; or to take for granted the genus ACTION, and to hunt for that of unqualified action. The negative aim of the dissertation is to argue against the standard approach; the positive aim is to develop an alternative. I first distinguish three different forms of generality---forms that are associated with the traditional ideas of an accident, a category and an essence. I then ask: What kind of generality is exemplified by each of the two canonical divisions? The standard approach is viable only if both divisions exemplify what I call "accidental generality." In fact, neither does. The division of action into qualified and unqualified action is an example of what I call "essential generality." I argue that, as in all such cases, the question, "What is unqualified action?" reduces into the question, "What is action?" The other division is an example of what I call "categorial generality." The concept "action" refers to a category of a distinctively practical kind: an agent must think that what she is doing falls under this category, if, in fact, it does fall under it. Then any attempt to describe a differentia must be circular: sooner or later it must refer the agent's thought; and the agent's thought must in turn make reference to that which it needed to explain. On the positive account defended here, an action is a certain sort of temporally-ordered system of ends and means. The claim is that the agent herself must think of what she is doing as being such a system---if, indeed, it is one.

By a concept , I mean a unitary thought (of the sort normally represented by a word) that applies to a plurality of differing objects, and by The Problem of Concepts I mean the pervasive philosophical questions of how such thoughts are to be explained and by what standards they are to be evaluated. Aristotle is generally held to have been a Moderate Realist, who held that a concept is a putative grasp of a mind-independent universal object that exist somehow in or derivatively on the many particular objects to which the concept applies. I argue that Aristotle rejected the posit of such universal objects and instead understood universality as a feature of thought, which has a basis in reality and a function in cognition. With some notable exceptions, concepts are based on relations of difference in the more and the less between their instances and on the causal relations between the various parts and characteristics of each instance. A concepts function is to serve as a term in deductions which enable us to represent the necessity of causal connections. I go on, then, to explore the manner in which, on Aristotles view, concepts compose propositions and bodies of knowledge and the way in which they are formed.

Meaningfulness in human affairs manifests itself in at least three ways: in thought, in speech, and in intentional action. In our day-to-day communicative interactions, we clearly presume to draw substantive, explanatory connections between these three: we hear what people say, we understand this as the expression of cognitive activity, and we see them engaging in intentional actions which, when all goes well, corroborate our attributions of specific cognitive states to them. I take this to embody rudimentary, though essentially correct, model of communicative understanding. My dissertation seeks to contribute to our understanding of this model and the constraints it imposes on a philosophical theory of meaning. A comprehensive theory of meaning, I argue, should provide a satisfactory account of all three elements of the model and of the conceptual and epistemic relations between them. Minimally, any sketch of a theory of meaning, however partial, should show it capable of serving in implementations of such a model. The bulk of my dissertation takes the form a critical exploration of Tyler Burges anti-individualism. Anti-individualism trades on the idea that normatively infused conventionally established concepts, shared among speakers of a language, must play a crucial role in underwriting cognition and communication. My dissertation constitutes a sustained argument to the effect that this strategy will not work. Its prima facie plausibility notwithstanding, I argue that theories taking this idea as their starting point will fail to satisfy the constraints laid out in the basic model, and will, as a consequence, end up misrepresenting the basic pattern of our communicative interactions.

I argue that trust is epistemically important because it is the foundation of social practices that confer significant epistemic benefits on scientific communities. I begin by showing the limitations of the dominant rational choice account of trust, which maintains that trust is rational when the truster has good reason to believe that it is in the trusted's self-interest to act trustworthily. These limitations motivate my alternative account of trust, which recognizes non-self-interested motivations for acting trustworthily, such as having a sense of duty. The first part of the account captures the cognitive aspect of trust. When we trust, we take a particular cognitive attitude towards the claim that the trusted will do what we expect her to do; I argue that this cognitive attitude can be either belief or acceptance, in the sense outlined by Michael Bratman. The second part of my account captures the emotional and moral aspects of trust by providing a framework to understand the connection between trust and betrayal—the feeling that usually results from being let down by a person one trusts. I provide an account of betrayal as a reactive emotion that connects it to beliefs about relational obligations. Thus when we trust, we depend on the trusted because we believe that our relationship with the trusted morally obliges her to act as expected. Using this account of trust, I argue that scientific communities can garner significant epistemic benefits when scientists are trustworthy and when they trust each other. Applying a framework adapted from Alvin Goldman's work on social epistemology, I argue that trust fosters epistemically beneficial sharing between scientists. These arguments are supported by a case study of the role that trust played in the achievements made by the community of early 20th Century Drosophilists. Finally, using recent examples of scientific fraud in cloning research and public policy responses to much-publicized 'crises in trust', I argue that the epistemic success of science results, in part, from science's ability to balance competition and cooperation, trust and distrust, self-interest and other-interest.