Knowledge: A Very Short Introduction

Citation

Nagel, J. (2014). Knowledge: A Very Short Introduction. Oxford University Press.

Chapter Summary

The book has eight chapters in about 150 pages, followed by further reading and an index. The publisher describes it as combining the classic questions of epistemology (what knowledge is, how it differs from belief, whether we need to justify a claim to know it, how we can know the outer world is not a dream) with newer puzzles arising from work on language and the mind, and as drawing on logic, linguistics and psychology. The sequence runs from the basic concept, through scepticism and the early modern theories, to the main twentieth-century debates, and ends with the psychology of how people attribute knowledge to one another.

Chapter 1: Introduction

Knowledge may belong to individuals or to groups, but the book focuses on knowledge as a link between a person and a fact: knowing that something is the case. The chapter asks how knowing differs from merely believing, introduces factivity (one can only know what is true), assumes that truth is objective, and notes that knowledge requires more than truth and confidence.

Chapter 2: Scepticism

Starting from the way even simple facts can seem doubtful once we reflect on them, the chapter traces scepticism to its two ancient traditions, the Academic and the Pyrrhonian, and their shared worry about the "criterion of truth". It then turns to modern responses: G. E. Moore's, Bertrand Russell's appeal to inference to the best explanation, and Hilary Putnam's semantic externalism as a reply to the brain-in-a-vat hypothesis.

Chapter 3: Rationalism and empiricism

The early modern contrast is illustrated by Descartes and Locke. Descartes in the Meditations takes a first-person approach, asking what he can know for certain; Locke takes a third-person approach, asking what human beings know and drawing on observation of others. Nagel links this choice of perspective to the modern division between internalism and externalism, which prepares the ground for Chapter 5.

Chapter 4: The analysis of knowledge

Gettier's counterexamples to the "classical analysis" of knowledge as justified true belief open the chapter. It follows the attempts to repair the analysis: a no-false-belief condition, Alvin Goldman's causal theory and then his reliabilism, on which knowledge is true belief produced by a reliable mechanism. It ends by asking whether knowledge can be analysed at all, contrasting "belief-first" and "knowledge-first" approaches to epistemology.

Chapter 5: Internalism and externalism

Internalism is presented as the first-person view that you know only if you can see for yourself why your belief is justified; externalism treats knowledge as a relation between a person and a fact that can hold without such access. The chapter covers Robert Nozick's tracking theory and the "generality problem" for reliabilist views, along with responses drawing on natural language and the science of belief formation.

Chapter 6: Testimony

Do we gain knowledge from what others tell us in a distinctive way, and do we need special reasons to trust them? Nagel lays out the spectrum from the view that testimony never provides knowledge to the view that it is a basic source on a par with perception and reasoning, with reductionism in between, and identifies the factors that matter most to how we absorb what people say. The publisher's description notes that the book's topics include the trustworthiness of internet sources.

Chapter 7: Shifting standards?

Some words, like "I", "now", "big" and "tall", change their content with context. Contextualism, which grew out of the relevant alternatives theory, claims that "know" behaves similarly, so that knowledge attributions shift with the situation. Its rival, invariantism, holds that the word does not shift, and must explain why knowledge sometimes seems easy to have and sometimes hard.

Chapter 8: Knowing about knowing

The last chapter turns to "mindreading", the natural capacity that produces instinctive judgements about what others know. Nagel explains that humans have specialised brain areas for tracking mental states but that the capacity has limits: on how many nested mental states we can represent, and from egocentrism, which makes it hard to set aside our own perspective when evaluating someone who knows less. She concludes that, even without a full account of what knowledge is, we are now better placed to make progress on the question.

Key Concepts

Chapters 1–2: Introduction; Scepticism

• Factivity: the feature of "knowing that" by which only truths can be known.
• Academic and Pyrrhonian scepticism: the two ancient sceptical traditions and their worry about a criterion of truth.
• Brain-in-a-vat hypothesis: the modern sceptical scenario, discussed with Putnam's semantic externalism as a reply.

Chapters 3–4: Rationalism and empiricism; The analysis of knowledge

• First-person versus third-person approach: Descartes's question of what I can know for certain versus Locke's question of what human beings know.
• Gettier problem: cases of justified true belief that are not knowledge.
• Reliabilism: knowledge as true belief produced by a mechanism likely to produce true beliefs.
• Knowledge-first: the view that knowledge cannot be analysed in terms of belief plus further conditions.

Chapters 5–6: Internalism and externalism; Testimony

• Internalism and externalism: whether knowledge requires first-person access to one's grounds.
• Tracking theory and the generality problem: Nozick's counterfactual account of knowledge, and the difficulty of specifying which process a reliability theory should assess.
• Reductionism about testimony: the middle position that testimonial knowledge depends on other reasons for trusting the speaker.

Chapters 7–8: Shifting standards?; Knowing about knowing

• Contextualism and invariantism: whether the standards expressed by "know" vary with the context of the speaker.
• Mindreading: the natural capacity to attribute knowledge and other mental states to others.
• Egocentrism: the bias that makes it hard to discount our own knowledge when judging others.

Critical Analysis

Strengths

• Classic and current together. The chapter sequence runs from ancient scepticism and Descartes and Locke to Gettier, reliabilism, knowledge-first epistemology and contextualism, so a short book still reaches the debates students meet in recent articles.
• Psychology and language as well as philosophy. Chapters 7 and 8 bring in linguistic context-sensitivity and research on mindreading and egocentrism, so the book shows epistemology in contact with linguistics and cognitive science rather than as a self-contained subject.
• Clear lines between positions. Each chapter is organised around a contrast (first-person versus third-person, internalism versus externalism, reductionism versus anti-reductionism about testimony, contextualism versus invariantism), which makes the field easy to map. Steven Poole in the Guardian called the book admirably clear and engaging.
• Everyday examples. The publisher stresses the use of everyday cases, including questions about internet sources, to explain the issues.

Limitations

• Breadth over depth. Eight major topics in about 150 pages means each position is introduced and then left. The contents list no study apparatus beyond further reading, so readers need another text to work through arguments in detail.
• Narrow conception of the subject. By its own statement the book concentrates on propositional knowledge held by individuals; group knowledge is mentioned at the start, and topics such as a priori knowledge, memory and the structure of justification (foundationalism and coherentism) do not have chapters of their own.
• An unusual ending. The final chapter is about the psychology of knowledge attribution rather than a summary of the philosophical debates, so students looking for a synthesis of the earlier chapters will need to make their own.

Where It Fits in the Course

This is the briefest of the epistemology introductions in the course and the best one to read first for an overview. Duncan Pritchard's What is this thing called Knowledge? is a fuller first textbook with short chapters, summaries, study questions and annotated further reading, and the natural next step. Noah Lemos's An Introduction to the Theory of Knowledge and Robert Audi's Epistemology: A Contemporary Introduction are more systematic textbooks that set out theories of knowledge and justification, and their objections, in detail; Nagel's chapters on scepticism, the analysis of knowledge and internalism/externalism give a quick orientation before their longer treatments.

Nagel's book also prepares the way for the two research monographs on the list. Chapter 4's discussion of knowledge-first epistemology leads directly to Timothy Williamson's Knowledge and Its Limits, the main statement of that view. Her account of reliabilism and the internalism-externalism debate gives background for Ernest Sosa's A Virtue Epistemology, which treats belief as a performance that can be apt and distinguishes animal from reflective knowledge.

How to Use This Book

No previous philosophy is needed. Read the whole book in the first week or two of the course; at about twenty pages per chapter, each can be read in one sitting. Chapters 1, 2, 4 and 5 form the core that every epistemology course will build on. Chapter 3 is valuable for courses with a historical component. Chapters 6 and 7 are central if your course covers testimony or contextualism, and Chapter 8 is best read with any course material on experimental philosophy or social cognition.

As you go, keep a one-page map of the contrasts the book draws and place each theory on it. For Chapter 4, write out each Gettier-style case and say which condition of the justified-true-belief analysis it attacks and which repair answers it. Then use the further reading and the longer textbooks in the course to follow up the two or three debates that interest you most.