The Sensory Order, first published in 1952, sets forth F. A. Hayek's classic theory of mind in which he describes the mental mechanism that classifies perceptions that cannot be accounted for by physical laws. Hayek's substantial contribution to theoretical psychology has been addressed in the work of Thomas Szasz, Gerald Edelman, and Joaquin Fuster.

PrefaceIntroductionI. The Nature of the Problem1. What is Mind?2. The Phenomenal and the Physical World3. Stimulus, Impulse, and the Theory of the Specific Energy of the Nerves4. Differences in Quality are Differences in the Effects5. The Unitary Character of the Sensory Order6. The Order of Sensory Qualities not Confined to Conscious Experience7. The Denial or Disregard of Our Problem by Behaviorism8. The 'Absolute' Qualities of Sensations a Phantom-ProblemII. An Outline of the Theory1. The Principle of the Explanation2. The Sensory Order in its Static and in its Dynamic Aspects3. The Principle of Classification4. Multiple Classification5. The Central ThesisIII. The Nervous System as an Instrument of Classification1. An Inventory of the Physiological Data2. Simplifying Assumptions on which the Operation of the Principle will be Discussed3. Elementary Forms of Classification4. Complex Forms of Classification5. The Classification of the Relation Between Classes6. The Universal Character of the Process of Classification: Gestalt Phenomena and Abstract ConceptsIV. Sensation and Behaviour1. Sensations and the Organism2. Evolution and the Hierarchal Order of the Nervous System3. From Specific Reflex to Generalized Evaluation4. Proprioception of Low-Level Responses5. Postures and Movements Connected with Perception6. Patterns of Motor Responses7. Biogenic Needs and Drives8. Emotions and the James-Lange TheoryV. The Structure of the Mental Order1. Pre-Sensory Experience or 'Linkages'2. The Gradual Formation of a 'Map' Reproducing Relations Between Events in the Environment3. The 'Map' and the 'Model'4. Associative Processes5. Mechanical and Purposive Behaviour6. The Model-Object RelationshipVI. Consciousness and Conceptual Thought1. Conscious and Unconscious Mental Processes2. Criteria of Consciousness3. The Common Space-Time Framework4. Attention5. The Functions of Consciousness6. 'Concrete' and 'Abstract'7. Conceptual ThoughtVII. Confirmations and Verification of the Theory1. Observed Facts for which the Theory Accounts2. Older Theories Comprised as Special Cases3. New Experiments Suggested4. Possibilities of Experimental RefutationVIII. Philosophical Consequences1. Pre-Sensory Experience and Pure Empiricism2. Phenomenalism and the Inconstancy of Sensory Qualities3. Dualisms and Materialism4. The Nature of Explanation5. Explanation of the Principle6. The Limits of Explanation7. The Division of the Sciences and the 'Freedom of the Will'BibliographyIndex