Abstract and Keywords
The Introduction discusses the purpose of the book, which is to attempt to rejuvenate the philosophy of concepts by steering it toward a new course. The book argues, the Introduction explains, that progress in the psychology of concepts and in the budding neuropsychology of concepts is conditional on psychologists and neuropsychologists eliminating the notion of concept from their theoretical vocabulary. This eliminativist proposal is the last tenet of the hypothesis that is developed at length in this book — the Heterogeneity Hypothesis. The Introduction then outlines to contents of the chapters that follow.
Once at the center of philosophy, the philosophy of concepts has now been marginalized, maybe because for a few years now, it has been stalled. The contrast with the psychology of concepts is stark. Psychologists working on categorization, induction, and reasoning have continued developing and refining their theories of concepts, discovering along the way a dazzling amount of phenomena. New work on prototypes in the 1990s and early 2000s, innovative ideas on causal cognition in the first decade of the twenty‐first century, the development of the neo‐empiricist approach to concepts, and the promising growth of the neuropsychology of concepts have rejuvenated the field.
Philosophers of concepts have not ignored the psychology of concepts, particularly the theories developed in the 1970s and 1980s. However, rather than addressing these psychological theories in their own terms, philosophers have viewed them as attempting to answer the questions that were of interest in the philosophy of concepts. Unsurprisingly, philosophers have typically found the psychological theories of concepts to be wanting and, instead of contributing to their development, have discarded them.
This book attempts to rejuvenate the philosophy of concepts by steering it toward a new course. The key novelty is to modify philosophers' relation to the psychology of concepts. Rather than viewing the theories and models developed by psychologists as naive and deficient answers to the questions of interest in philosophy, I examine them in their own terms, without any preconception about the goals that psychologists attempt to (p.4) meet. I argue that progress in the psychology of concepts and in the budding neuropsychology of concepts is conditional on psychologists and neuropsychologists eliminating the notion of concept from their theoretical vocabulary. This eliminativist proposal is the fifth and last tenet of the hypothesis that is developed at length in this book—the Heterogeneity Hypothesis:
1. The best available evidence suggests that for each category (for each substance, event, and so on), an individual typically has several concepts.
2. Coreferential concepts have very few properties in common. They belong to very heterogeneous kinds of concept.
3. Evidence strongly suggests that prototypes, exemplars, and theories are among these heterogeneous kinds of concept.
4. Prototypes, exemplars, and theories are typically used in distinct cognitive processes.
5. The notion of concept ought to be eliminated from the theoretical vocabulary of psychology.
Chapters 1 and 2 are two introductory chapters. Chapter 1 describes what concepts are taken to be in psychology and identifies the goals of psychological theories of concepts. These goals, and only these goals (not the goals that philosophers of concepts attempt to meet), provide the relevant criteria for evaluating psychological theories of concepts. I propose that in psychology, concepts are characterized as being those bodies of knowledge that are stored in long‐term memory and that are used by default in the processes underlying most, if not all, higher cognitive competences when these processes result in judgments about the referents of these concepts. Theories of concepts attempt to describe the knowledge stored in concepts, the format of concepts, the cognitive processes that use concepts, the acquisition of concepts, and the localization of concepts in the brain. By doing so, they can explain the properties of people's higher cognitive competences.
Chapter 2 describes what concepts are taken to be in philosophy and identifies the goals of philosophical theories of concepts. Together, chapters 1 and 2 show that when philosophers and psychologists develop theories of concepts, they are really theorizing about different things. This conclusion undercuts many of the arguments made by philosophers against psychological theories of concepts.
Chapter 3 develops at length the Heterogeneity Hypothesis, with a special focus on the first two tenets. While most psychologists assume that there are numerous properties common to all concepts (the Received View), I propose that the class of concepts divides into kinds that have little in common. The Heterogeneity Hypothesis is also contrasted with theories of concepts that are superficially similar—namely, hybrid theories of concepts—in order to prevent their conflation.
(p.5) Chapter 4 describes the theoretical entities that have been proposed by the main views of concepts developed since the 1970s—prototypes, exemplars, and theories. More recent approaches to concepts, particularly the neo‐empiricist view of concepts, are also discussed. While philosophers have typically been satisfied with cartoonish versions of the psychological theories of concepts, I look closely and critically at these theories and at the models of cognitive processes developed by psychologists. This examination leads to the conclusion that given the properties that are relevant to characterize concepts, prototypes, exemplars, and theories have very little in common. This shows that if prototypes, exemplars, and theories exist, the class of concepts divides into kinds that have little in common.
Chapter 5 focuses on the fourth tenet of the Heterogeneity Hypothesis. The goal of this chapter is to investigate, in a somewhat speculative manner, the contours of those theories that assume that a single cognitive competence, for instance, inductive reasoning, is underwritten by several cognitive processes (a kind of theory I call ‘multi‐process theories’).
Chapters 6 and 7 discuss the empirical evidence showing that prototypes, exemplars, and theories exist (Tenet 3 of the Heterogeneity Hypothesis), and that they are used in distinct cognitive processes (Tenet 4). Chapter 6 focuses on the vast research on categorization. I establish that we have at least three processes of categorization, each of which involves a specific kind of concept—namely, prototypes, exemplars, and theories.
Chapter 7 focuses on the research on inductive reasoning and concept combination. These two fields provide converging evidence for the Heterogeneity Hypothesis. Findings from the growing field of the neuropsychology of concepts are also critically assessed.
Let us take stock. Chapter 1 establishes that for psychologists, concepts are those bodies of knowledge that are used in the processes underlying the higher cognitive competences. Chapter 4 describes the main theoretical entities posited by psychologists of concepts—prototypes, exemplars, and theories—and contends that these theoretical entities have little in common. Chapters 6 and 7 show that prototypes, exemplars, and theories exist and are used in distinct categorization processes and distinct induction processes. I conclude that the class of concepts divides into kinds that have little in common.
The last chapter, Chapter 8, draws the conclusion of this line of reasoning: the notion of concept should be eliminated from contemporary psychology. Previous eliminativist arguments are considered and are judged to be inconclusive. A new type of eliminativist argument called ‘scientific eliminativism’—showing that the extension of a scientific notion is not a natural kind—is developed and applied to concepts. I show that concepts are not a natural kind, and I conclude that if psychology is to progress further, the notion of concept ought to be eliminated from its theoretical vocabulary.
Here are a few practical details before pursuing at length this line of reasoning in the remainder of the book. I have attempted to restrict the (p.6) footnotes to bibliographical references and terminological remarks. As a result, this book can pretty much be read without consulting them. Moreover, because I have brought together many disciplines, and because I hope to be read by diverse audiences, I have shunned the technical jargon as much as possible. When this was impossible, I have explained what the relevant technical terms meant. Because these terms do not always mean the same thing in different disciplines, I ask readers to forego their preconceptions about what these technical terms mean for them.
Finally, many of the topics discussed in this book are empirical and some might find it strange that a philosopher dabbles so thoroughly in empirical issues. Would it not be better to leave scientific questions to scientists and to focus on strictly philosophical issues? This is not my view, however. Save, maybe, for purely formal (e.g., logical) theories, philosophical claims whose correctness does not depend, however indirectly, on matters of fact are empty: they are neither true nor false. As I see it, philosophy is the pursuit of empirical knowledge by (typically, though not exclusively) conceptual means: philosophy is in the business of examining, criticizing, reforming the findings, theories, methods developed by scientists and of grasping the implications of sciences for our understanding of the world and our place in it.