Laws of Nature

by

Marc Lange

• LAST REVIEWED: 21 November 2022
• LAST MODIFIED: 24 July 2012
• DOI: 10.1093/obo/9780195396577-0160

Introduction

The discovery of the laws of nature has long been considered a principal aim of science. Of course, many laws that science discovers are not commonly designated “laws.” Alongside Boyle’s law, the law of universal gravitation, and the law of supply and demand, there are Archimedes’ principle, Maxwell’s equations, and the formulas of stoichiometry. Philosophy does not aim to account for the use of the term “law” or to discover the natural laws. Rather, philosophy strives to understand what it is that scientists discover when they discover laws. Philosophers have generally distinguished laws from “accidents” (that is, from contingent facts that are not matters of law) on several grounds. First, laws stand in especially intimate relations to subjunctive conditionals and counterfactual conditionals. Second, laws can explain why various facts hold. Third, laws help to give causes their powers to produce their effects. Fourth, laws restrict what is possible in nature; laws are universal and cannot be violated. (They possess “natural necessity.”) Fifth, laws specify the properties characteristic of various natural kinds. Sixth, when scientists confirm that some general hypothesis makes accurate predictions regarding each of the unexamined cases there might be, lying in a vast range, scientists are often basing their inductive reasoning on the presupposition that this hypothesis may be a law. Thus, laws are central to a wide range of core topics in metaphysics and epistemology. A philosophical account of natural law must refine these various respects in which laws are supposed to differ from accidents. It must then specify what laws are such that they are capable of playing their distinctive scientific roles. A wide variety of rival accounts of law has been proposed. Some philosophers defend “non-Humean” accounts, according to which laws are constituted by irreducible necessities, subjunctive facts, essences, or causal powers—or laws are themselves fundamental rather than reducible to other sorts of facts. Other philosophers defend “Humean” accounts, according to which the laws are reducible entirely to some non-modal features of the universe’s actual past, present, and future history, together perhaps with some features of scientists, their theories, or their practices. Yet other philosophers deny that the category of “laws of nature” is helpful for understanding science or reality. Some philosophers investigate the extent to which laws arise in the biological and social sciences. Although the nature of natural law was of great interest to early modern philosophers, this article is confined to works of analytic philosophy after 1945.

General Overviews

Bird 1998 and Lange 2008 are elementary, accessible, and self-contained introductions to the topic. Psillos 2002 goes into considerably more detail regarding various rival accounts. Though Armstrong 1983 and van Fraassen 1989 defend their own particular views regarding natural law, they cover insightfully a wide range of other approaches as well as elaborate the roles that laws have widely been thought to play in science. Carroll 2010 is a thorough survey; for virtually any topic in philosophy, the online Stanford Encyclopedia of Philosophy is a superb resource, with up-to-date articles written by leading figures in the field (e.g., Carroll 2010).

• Armstrong, David. What Is a Law of Nature? Cambridge, UK: Cambridge University Press, 1983.

  A pioneering book-length treatment of the topic of natural law. Careful elaboration of the importance of the topic for science and philosophy, the challenges facing Humean accounts (especially Lewis’s), and the resources available to Armstrong’s own non-Humean proposal.

• Bird, Alexander. Philosophy of Science. Montreal: McGill-Queen’s University Press, 1998.

  DOI: 10.4324/9780203165348

  An introductory textbook. The first chapter (pp. 25–60) gives a fair-minded, straightforward, readable survey of the topic of laws of nature. Recommended for beginning students.

• Carroll, John. “Laws of Nature.” In The Stanford Encyclopedia of Philosophy. Edited by Edward M. Zalta. 2010.

  Clear discussion of the core controversies and positions. Includes a useful bibliography.

• Lange, Marc. “Laws of Nature.” In The Routledge Companion to Philosophy of Science. Edited by Stathis Psillos and Martin Curd, 203–212. Abingdon, UK: Routledge, 2008.

  Brief survey of the roles that natural laws have traditionally been thought to play in scientific reasoning and of the major philosophical accounts of what laws consist of.

• Psillos, Stathis. Causation and Explanation. Montreal: McGill-Queen’s University Press, 2002.

  An accessible textbook with detailed discussions of many proposed accounts of natural law.

• van Fraassen, Bas C. Laws and Symmetry. Oxford: Clarendon, 1989.

  Elaborates the most common reasons for believing laws to be important discoveries of science, ultimately arguing that they are not compelling. Devotes several chapters to evaluating critically each of several major proposed accounts of natural law.