PHI403 Lecture 08 — Have Your Cause and Beat It

On interference: the reason causes fail to produce their effects is that the world contains preventers and disturbers. The lecture distinguishes:

Subtractive interference — remove a causal factor (quit smoking). Sometimes impossible (cannot remove the Sun).
Additive interference — add a counteracting factor (air-conditioner). Critically, you can "have your cause and beat it" — A is genuinely present and causally active, yet B does not follow.
Antipathetic interference — two causes in combination produce the opposite of their individual effects (clonidine + beta-blockers).

Additive interference is a direct refutation of constant-conjunction causation: A can cause B while also sometimes not being followed by B, purely because of an added interferer. The Humean response is causal expansion: include all the relevant conditions in the cause. But expansion either never ends (the cause swallows the world) or remains fragile (each new factor is itself subject to interference). Causal isolation and expansion do not prove "same cause, same effect" — they assume it.

This lecture is where the course's interventionist commitments are most visible: interference is what makes intervention possible.

Connections

Back-link: sources/2023-anjum-rocca-phi403-causation-in-science. Concepts: concepts/interventionist-theory-of-causation · concepts/regularity-theory-of-causation · concepts/dispositionalism.