Counterfactuals and Causation
A natural thought is that a cause is something without which the effect would not have happened. This topic develops that idea into the counterfactual analysis of causation and examines its semantics and its well-known problems.
Definition
The counterfactual theory analyzes causation in terms of counterfactual dependence: roughly, c causes e when, had c not occurred, e would not have occurred.
Scope
Covers the Stalnaker-Lewis possible-worlds semantics for counterfactual conditionals, Lewis's counterfactual analysis of causation as the ancestral of counterfactual dependence, and challenges from preemption, overdetermination, and transitivity.
Core questions
- How should counterfactual conditionals be interpreted?
- Can causation be reduced to counterfactual dependence?
- How does the theory handle preemption and overdetermination?
- Is causation transitive?
Key concepts
- Counterfactual conditional
- Counterfactual dependence
- Closest possible world
- Similarity ordering
- Preemption
- Transitivity
Key theories
- Possible-worlds semantics for counterfactuals
- Stalnaker and Lewis evaluate a counterfactual by considering the closest possible worlds in which its antecedent holds and checking whether the consequent holds there, using a similarity ordering of worlds.
- Counterfactual analysis of causation
- Lewis defines causal dependence via counterfactuals and identifies causation with the ancestral of causal dependence, so causation is chains of counterfactual dependence among distinct events.
History
Stalnaker and Lewis developed possible-worlds semantics for counterfactuals around 1968-1973. Lewis then built his counterfactual theory of causation, which became the dominant analysis. Subsequent decades saw extensive work refining it to handle preemption and overdetermination, including influence by structural-equations and interventionist models.
Debates
- Can the counterfactual theory handle preemption?
- In preemption, the effect does not counterfactually depend on its actual cause because a backup would have produced it. Lewis and successors proposed fragility, stepwise dependence, and structural-equations refinements; critics doubt these fully succeed.
Key figures
- David Lewis
- Robert Stalnaker
- Peter Menzies
- L. A. Paul
- Ned Hall
Related topics
Seminal works
- lewis1973causation
- lewis1973counterfactuals
Frequently asked questions
- What is counterfactual dependence?
- Event e counterfactually depends on event c when, had c not occurred, e would not have occurred. Lewis's theory builds causation out of chains of such dependence, analyzing the counterfactuals using possible worlds ordered by similarity.