P.M.S. Hacker is the leading authority on the philosophy of Wittgenstein. He has specialized in philosophy and cognitive neuroscience. He has written a four-volume tetralogy on human nature of which three have been published.

LIST OF ABBREVIATIONS; I. WITTGENSTEIN'S EARLY CONCEPTION OF PHILOSOPHY; 1. Background; 2. The 'Preliminary' on Philosophy; 3. Philosophy and Illusion 4. Philosophy as Critique and as Analysis; II. THE DIALOGUE WITH FREGE AND RUSSELL; 1. Agreements and Disagreements; 2. The Grundgedanke of the Tractatus; 3. The Laws of Logic; 4. A Prelude to Conventionalism; III. MEANING, METAPHYSICS, AND THE MIND; 1. The Picture Theory of Meaning; 2. The Metaphysics of the Tractatus; 3. Connecting Language with Reality: The Role of the Mind; IV. EMPIRICAL REALISM AND TRANSCENDENTAL SOLIPSISM; 1. The Self of Solipsism; 2. 'I Am My World'; 3. 'The Limits of Language Mean the Limits of My World'; 4. Later Years; V. DISINTEGRATION AND RECONSTRUCTION; 1. The Colour-Exclusion Problem; 2. Dismantling the Tractatus; 3. The Brouwer Lecture; 4. Moving off in Fresh Directions; 5. The Vienna Circle and Wittgenstein's Principle of Verification; VI. WITTGENSTEIN'S LATER CONCEPTION OF PHILOSOPHY; 1. A Kink in the Evolution of Philosophy; 2. A Cure for the Sickness of the Understanding; 3. Philosophy, Science, and Description; 4. Philosophy and Ordinary Language; 5. The Phenomenology and Sources of Philosophical Illusion; 6. Systematic Philosophy; VII. METAPHYSICS AS THE SHADOW OF GRAMMAR; 1. Grammar; 2. The Autonomy of Grammar; 3. Grammar and Metaphysics; 4. A Note on Kant and Wittgenstein; VIII. THE REFUTATION OF SOLIPSISM; 1. Introduction; 2. From Transcendental Solipsism to Methodological Solipsism; 3. The Solipsist's Predicament: A Restatement and Second Diagnosis; 4. The Refutation; IX. PRIVATE LINGUISTS AND PUBLIC SPEAKERS; 1. A Disease of the Intellect; 2. Following Rules; 3. Philosophical Investigations; 4. The Private Language; 5. The Epistemology of the Private Linguist; 6. Wittgenstein's Criticism of the Private Language; 7. 'Only I Know' and 'Only I have'; X. 'A CLOUD OF PHILOSOPHY CONDENSED INTO A DROP OF GRAMMAR'; 1. Can One Know That One Is in Pain?; 2. Self-Consciousness: the Overthrow of the Cartesian Picture; 3. The 'Inner' and the 'Outer'; 4. Experience and Its Natural Expression; 5. Avowals and Descriptions; 6. Objections and Deflections; XI. CRITERIA, REALISM, AND ANTI-REALISM; 1. The Origin of the Idea; 2. Plotting the Contour-lines; 3. Further Complications; 4. Red Herrings: Realism and Anti-Realism; INDEX.