Kant’s distinction between intuitions and concepts attracts perennial interpretive interest. To the extent that they discuss the imagination at all, most Kant scholars maintain that the imagination’s primary role is to generate intuitions. This dissertation argues that “image” (Bild, Einbildung) is an overlooked technical term in Kant’s work and that images—and not intuitions—are products of the imagination. The project explains how, for Kant, the imagination (as image-maker) and the senses (as intuition-maker) make distinct but essential contributions to cognition and perception. I begin by showing that “image” is a terminologically marked notion in Kant, and that the imagination is responsible for generating images (chapter 1). I call these claims the Image Thesis. I then show that for Kant, intuitions are representations that depend only on the senses for their essential features (chapter 2). I call this the Strong Independence Thesis.

How should we understand Kant’s ubiquitous references to the imagination, then? I argue that we should understand the imagination’s activities as image-producing activities (chapter 3). I argue that images and intuitions are fundamentally distinct representations, which I label the Distinctness Thesis. Though intuitions and images are had by both rational and non-rational beings, the capacity for consciousness or apperception found in rational beings makes a difference in the structure of images but not the structure of intuitions (chapter 4). I call this the penetration view of the imagination. With this account of images in hand, I indicate why images are a necessary ingredient in theoretical cognition for Kant (chapter 5). I call this the Image-Centric Cognition Thesis. The result is a novel account of sensibility—the counterpart of the understanding—that recognizes Kant’s systematic discussion of mental imagery.

The aim of this PhD is to make headway in understanding Kant’s theory of cognition, and my strategy in pursuing that aim is to investigate his account of concept-formation. I argue that what Kant has to say on this topic is more extensive and insightful than has previously been recognized, and that it bears directly on his theory of cognition. To reach this conclusion, the dissertation splits into three parts. Part 1 lays out some fundamental doctrines in Kant’s theory of concepts and articulates the various interpretive approaches that have been taken to them. I show here that Kant’s account of concept-formation assumes a hylomorphic account of concepts, which distinguishes them into a universal form and a given ‘matter’ — a set of given, intrinsicially non-conceptual representations that constitute the subjective generation-base of the concept. A proper account of the origins of concepts, by Kant’s own lights, must explain both the ‘matter giving’ acts that bring these nonconceptual representations to consciousness and the ‘form imparting’ acts that convert them into concepts. The second and third parts of the dissertation explore, respectively, the material and formal dimensions of Kant’s account of the origins of concepts. Part 2 studies the matter-giving acts that pertain to the origin of ‘sensible’ concepts (Chapters 3 and 4), and the concepts ‘of understanding’ or categories (Chapter 5). The act that Kant names apprehension, I argue, is the common matter-giving act underlying all sensible concepts; reflection, I argue, is the act that underlies the categories. This account has the revisionary implication that Kant’s doctrine of imagination has its primary theoretical home within his account of concept-formation, not, as is commonly assumed, in his account of intuition-formation. The final part epxlores the three ‘logical acts’ to which Kant famously traces the universal form of concepts: comparison, reflection, and abstraction. Chapter 6 deals with the relationship between comparison and schemata; Chapter 7 situates the doctrines of reflection and abstraction within Kant’s account of the unity of apperception; and Chapter 8 draws on the findings of Chapter 7 to make good on the suggestion that the categories of understanding originate in reflection. The result is an account that clarifies key doctrines from Kant’s published works and also yields a heterodox conception of both the nature of concepts and the relationship between intellect and sensibility. On the account I propose, Kantian concepts are not mere rules or dispositions: they are mental representations of properties, whose content is fixed prior to and indepedently of the judgments in which they can feature. And the faculty of understanding, I argue, is much more intimately connected with the faculty of sensibility than has been supposed. Though my reading stops short of collapsing the distinction between understanding and imagination, it makes the case that understanding depends not merely causally but constitutively on the faculty of sensibility, and that the traces of sensibility can be detected both in the essence of the faculty of understanding and in the contents of its pure concepts.

My dissertation defends a non-mechanistic interpretation of Kant’s philosophy of nature. Inspired by the picture of nature in the Critique of Pure Reason and Metaphysical Foundations of Natural Science, most readers align Kant with Early Modern mechanists, who claim that we can know that the internally purposive form of causality characteristic of organisms has no place in nature. To these mechanistic readers, Kant banishes internal purposiveness from nature. To moderate mechanistic interpreters, because we cannot know whether there are internally purposive things in nature and we can demonstrate that mechanism applies to nature, Kant pushes us to believe that any seemingly internally purposive natural products will eventually be explained in mechanistic terms. To strong mechanistic interpreters, Kant gives us the tools to know that there is no room for the special kind of teleology organisms exhibit in nature. My non-mechanistic interpretation rejects this trend by arguing that Kant urges us to believe that the internally purposive activity characteristic of organisms exists in nature. Belief in this context is a firm, positive, and voluntary attitude that aligns with and serves a subject’s interests and ends, and that has implications for the subject’s rational action, assertion, and deliberation. Kant’s stated goal in the third Critique is to bridge the gulf between freedom and nature. My non-mechanistic interpretation offers a new account of how Kant promises to construct this bridge.

Understanding the “intentionality” of mental phenomena is widely regarded as a key problem in philosophy of mind. Franz Brentano (along with his students, especially Edmund Husserl) is widely credited with bringing intentionality to philosophers’ attention. In early treatment by the Brentano school, intentionality is at least nominally understood as executed, brought about, or achieved in mental acts. And in the early 20th century, historians of psychology regarded this “act conception” of intentionality as integral for understanding the phenomenon. Yet the secondary literature on Brentano and Husserl provides no clarification of mental acts as acts, and in contemporary philosophy, we have no workable account of what it could mean for intentionality to arise through mental acts. The main difficulty is that “act” is widely regarded as synonymous with “volitional personal action.” Since we as human agents certainly do not willfully bring about much of our own mental life, and since (on the standard analyses) all such volition presupposes intentionality, it is a mystery to work out what the act conception of intentionality could have amounted to.

This dissertation is a systematic explication of the historical act concept of intentionality. Part I examines Brentano. I show that his early work on Aristotle’s psychology provides resources to think coherently about many mental phenomena as acts, even if they are not personal actions. However, I also show that Brentano’s mature psychology is not Aristotelian, at least insofar as it does not (and cannot) deploy an Aristotelian conception of mental acts. Part II examines Husserl. I show that Husserl’s mature transcendental phenomenology works with a robust and many-layered conception of mental acts, and that understanding intentionality as active is essential to the phenomenological viewpoint. Moreover, I argue that Husserl’s conception of mental acts can be viewed as a transcendentalized, neo-Aristotelian view.

The results will be of special interest to historians of philosophy, but also have a much broader significance. Husserl’s view provides us with a model of what can be called an “internalist enactivism.” Any view along these lines represents a novel position that has not been articulated (or even considered) in contemporary debates.

This dissertation concerns a topic that has been unduly neglected by historians of Early Modern philosophy and philosophers of mathematics alike: the highly original conception of number advanced by Gottfried Wilhelm Leibniz in the seventeenth and early eighteenth centuries. I aim to answer several questions regarding that conception, thereby illustrating its historical and philosophical importance: (1) How does Leibniz define the concept of number?; (2) Into which ontological category does Leibniz think numbers fall?; (3) Which sorts of numbers — e.g. rational, irrational, complex — does Leibniz think are conceptually legitimate, and to what extent does he realize that his own definitions commit him to the acceptance of certain kinds of numbers as such?; and (4) How does Leibniz think we acquire knowledge about numbers?

In the course of answering these questions, I aim to show that Leibniz’s conception of number is philosophically significant insofar as it unites the most productive aspects of earlier conceptions into one that goes a long way toward allowing him to accommodate numbers that had not been previously viewed as conceptually legitimate (e.g. irrationals and complex numbers); provides an original ontology of number as a certain kind of relation; and anticipates the core views of the logicist school in the philosophy of mathematics.

The dissertation is organized in a way that reflects the four core questions: I begin by discussing the intellectual climate in seventeenth-century mathematics in Chapter 1; I move on to an analysis of Leibniz’s conceptual characterization of number in Chapter 2; I argue that this characterization is consistent with Leibniz’s ontology of number (and explain the nature of that ontology) in Chapter 3; I discuss the scope of Leibniz’s view of number in Chapter 4, arguing that he is committed to the existence of different sorts of non-rational numbers, while also delineating the conceptual and technical limitations of his views; I explain his epistemology of number in Chapter 5; and I close by arguing that his views — conceptual, ontological, and epistemological — anticipate those of the logicists in Chapter 6.