The Character of Consciousness by David Chalmers

Context

The Character of Consciousness, published in 2010 by Oxford University Press, collects seventeen of David Chalmers' papers on consciousness from the period 1995–2010, including several previously unpublished or hard-to-find pieces, together with a new introduction and a set of replies. It is the sequel and complement to The Conscious Mind (1996): where the earlier book built the case for the hard problem and naturalistic dualism, the collection develops the details — the two-dimensional framework, the semantics of phenomenal concepts, the structure of consciousness, and the prospects for a science of consciousness.

The book is organized into four parts. Part I contains the central papers on the hard problem and its relation to the science of consciousness. Part II develops the two-dimensional semantic framework. Part III contains the papers on the contents and structure of consciousness. Part IV treats the metaphysics of consciousness, including the famous paper "Does Conceivability Entail Possibility?" The book's title signals its subject: the character of consciousness — its phenomenal character, its structure, and its place in nature.

Core Arguments

The Hard Problem and Its Developments

The collection opens with the definitive statements of the hard problem. In "Facing Up to the Problem of Consciousness" and "Moving Forward on the Problem of Consciousness," Chalmers argues that the hard problem — why physical processes are accompanied by experience — is distinct from the easy problems of cognitive function and will not be solved by the methods that solve them. The collection also contains "The Meta-Problem of Consciousness" (a later paper added to the second edition), which asks why we think consciousness is hard to explain — a problem Chalmers considers tractable and central to the future of the field.

The Two-Dimensional Framework

The book develops the two-dimensional semantics first sketched in The Conscious Mind. Chalmers argues that the epistemic and metaphysical dimensions of meaning can be modeled with primary and secondary intensions, and he applies the framework to the philosophy of mind: the conceivability of zombies and inverted qualia, the nature of phenomenal concepts, and the epistemology of the physical world. The papers on two-dimensionalism — including "The Foundations of Two-Dimensional Semantics" — are among the most technically substantial in the collection and have influenced the philosophy of language and epistemology as well as the philosophy of mind.

Phenomenal Concepts and the Explanatory Gap

A central theme is the problem of phenomenal concepts: how we can think about experiences in first-person terms. Chalmers argues that phenomenal concepts are recognitional concepts grounded in our ability to discriminate and recognize the phenomenal character of our own experience. He uses this account to sharpen the explanatory gap: the gap between physical and phenomenal concepts is not a mere epistemic inconvenience but a deep feature of our conceptual scheme, reflecting the fact that experience is not conceptually reducible to the physical. This analysis defends the intuition behind the hard problem against the "phenomenal concept strategy" of physicalists.

The Neural Correlates of Consciousness

The collection engages directly with the empirical science of consciousness. In "What Is a Neural Correlate of Consciousness?" Chalmers analyzes the concept of the NCC — the minimal neural system jointly sufficient for a conscious state — and argues that identifying NCCs is the central empirical task of consciousness science. In "How Can We Construct a Science of Consciousness?" he proposes that a complete science of consciousness will require not only NCCs but also laws connecting physical and phenomenal properties — psychophysical laws — and he surveys the prospects for theories like the global workspace theory and integrated information theory.

The Structure of Consciousness

Part III contains Chalmers' papers on the contents and structure of experience: the unity of consciousness, the relationship between perception and the world, the "matrix" hypothesis (that we might be in a virtual world), and the possibility of the extended mind. These papers apply the two-dimensional framework to specific questions about what experience is like and how it is organized.

Key Concepts

The collection's key concepts — the hard problem, the meta-problem, phenomenal concepts, the explanatory gap, the two-dimensional framework, primary and secondary intensions, the neural correlate of consciousness, psychophysical laws, the unity of consciousness, and the matrix hypothesis — constitute the most complete toolkit in the contemporary philosophy of consciousness. The book also contains Chalmers' influential analysis of "the content of perception" and his argument for the "principle of organizational invariance" in the context of artificial consciousness.

Legacy & Influence

The Character of Consciousness consolidates Chalmers' position as the leading philosopher of consciousness of his generation. The papers collected here have shaped the two main debates in the field: the debate between physicalists and their critics (through the hard problem, the zombie argument, and phenomenal concepts) and the debate about how to build a science of consciousness (through the NCC and psychophysical laws). The two-dimensional framework has influenced philosophy of language and epistemology, and the meta-problem has become a major research topic, connecting philosophy to psychology and the study of introspection. The book is essential reading for anyone working on consciousness, and it shows the extraordinary range and rigor of Chalmers' approach.

Reading Guide

The book can be read selectively. For the core of Chalmers' position, read Part I, especially "Facing Up to the Problem of Consciousness" and "Moving Forward on the Problem of Consciousness." For the technical framework, read the two-dimensionalism papers in Part II. For the science of consciousness, read the NCC and science-of-consciousness papers in Parts I and IV. Each paper stands alone, and the introduction provides an excellent map of the whole. The answer pages on the hard problem and the explanatory gap provide accessible entry points.

Related Works

The book is the sequel to Chalmers' The Conscious Mind (1996). Its account of the NCC connects to the work of Christof Koch and Giulio Tononi on the neuroscience of consciousness, and its defense of the hard problem continues the tradition of Thomas Nagel's bat argument and Frank Jackson's knowledge argument. Its opponents are the physicalist theories of Daniel Dennett in Consciousness Explained (1991) and the eliminativism of Patricia Churchland, and its treatment of the matrix hypothesis connects to the simulation hypothesis.