© 2014

The Concept of Reduction


  • Explores the history and role of reduction in philosophy of science and philosophy of mind

  • Offers a new, coherent framework within which various notions of reduction can be defined

  • Sheds light on the relation between reductive explanation and neighboring topics, such as mechanistic explanation, unification, levels in science, and metaphysical dependence


Part of the Philosophical Studies Series book series (PSSP, volume 121)

Table of contents

  1. Front Matter
    Pages i-xii
  2. Raphael van Riel
    Pages 1-8
  3. The Concept of Reduction – An Explication

    1. Front Matter
      Pages 9-9
    2. Raphael van Riel
      Pages 39-52
    3. Raphael van Riel
      Pages 83-126
  4. The Explication at Work

    1. Front Matter
      Pages 127-127
    2. Raphael van Riel
      Pages 129-151
    3. Raphael van Riel
      Pages 185-201
    4. Raphael van Riel
      Pages 203-224
    5. Raphael van Riel
      Pages 225-226

About this book


This volume investigates the notion of reduction. Building on the idea that philosophers  employ the term ‘reduction’ to reconcile diversity and directionality with unity, without relying on elimination, the book offers a powerful explication of an “ontological”, notion of reduction the extension of which is (primarily) formed by properties, kinds, individuals, or processes. It argues that related notions of reduction, such as theory-reduction and functional reduction, should be defined in terms of this explication. Thereby, the book offers a coherent framework, which sheds light on the history of the various reduction debates in the philosophy of science and in the philosophy of mind, and on related topics such as reduction and unification, the notion of a scientific level, and physicalism.


The book takes its point of departure in the examination of a puzzle about reduction. To illustrate, the book takes as an example the reduction of water. If water reduces to H2O, then water is identical to H2O – thus we get unity. Unity does not come at the price of elimination – claiming that water reduces to H2O, we do not thereby claim that there is no water. But what about diversity and directionality? Intuitively, there should be a difference between water and H2O, such that we get diversity. This is required for there to be directionality: in a sense, if water reduces to H2O, then H2O is prior to, or more basic than water. At least, if water reduces to H2O, then H2O does not reduce to water. But how can this be, if water is identical to H2O? The book shows that the application of current models of reduction does not solve this puzzle, and proposes a new coherent definition, according to which unity is tied to identity, diversity is descriptive in nature, and directionality is the directionality of explanation.


Conceptions of Reduction in the Philosophy of Science Definition Reduction Functional Reduction How to Approach Reduction Hyper-Intensionality Identity in Mechanistic Explanation Mechanistic Explanation Metaphysical Explanation Metaphysical dependence Metaphysics Naturalism Non-Reductive Physicalism Ontological Reduction Physicalism Reduction Water H2O Reduction in the Philosophy of Mind Reductionism Reductive Explanation Scientific Levels Scientific Reduction Theory Reduction Token Identity Theory Type-Identity Theory Ways of defining reduction

Authors and affiliations

  1. 1.Institut für PhilosophieUniversität Duisburg-EssenEssenGermany

Bibliographic information