Nancy Cartwright

Nancy Cartwright is an American philosopher of science who has taught at Stanford, the London School of Economics, Durham University and the University of California, San Diego. In How the Laws of Physics Lie she argued that fundamental explanatory laws, read as literal descriptions of fact, are false, and that once made true they lose their explanatory force. She holds that laws describe capacities of things, and has applied this to economics and evidence-based policy.

Key ideas

• Fundamental laws are idealisations: true of models rather than literal descriptions of the messy world.
• Science is better described by capacities or powers of things than by universal regularities.
• The world is 'dappled': laws hold only within specific, carefully arranged settings (nomological machines).
• Evidence that a policy worked in one place does not show it will work elsewhere unless the same causal structure is present.

Major works

• How the Laws of Physics Lie (1983)
• Nature's Capacities and Their Measurement (1989)
• The Dappled World (1999)
• Hunting Causes and Using Them (2007)

In the conversation

• Question Friedman’s billiard player: is predictive success really all a model owes us? Wanjiru Njenga · 4 replies
• Debate Cartwright is right: the fundamental laws of physics are false of real things, and that’s fine Abdulrahman Al-Bassam · 5 replies
• Debate There can be no laws of human behaviour, only useful regularities Javier Ferrandis · 5 replies