---
title: "PHI403 Lecture 07 — One Effect, One Cause?"
type: source
tags: [philosophy-of-science, causation, complexity, monocausality, inus, manifestation-partners]
authors: [Anjum, Rani Lill; Rocca, Elena]
year: 2023
venue: "PHI403 Causation in Science, NMBU"
kind: handout
raw_path: "raw/Philosophy of Science/PHI302 07 One Effect One Cause.pdf"
created: 2026-04-20
updated: 2026-04-20
key_claims:
  - Monocausality — one effect, one cause — is a methodological simplification, not a feature of reality.
  - Multiple causality takes two main forms: overdetermination (redundant causes) and joint causation (Mackie's INUS conditions).
  - C.B. Martin's "mutual manifestation partners": a cause cannot act alone; the fire needs flammable material and oxygen.
  - Context determines which of a cause's many possible effects manifests; heating produces boiling, melting, fever, growth, drought, etc., depending on what else is present.
---

# PHI403 Lecture 07 — One Effect, One Cause?

Challenges the methodological habit of seeking *the* cause — singular — of an effect. Most real effects are produced by **many causes working together**; isolating "the" cause is a simplification.

- **Overdetermination** — more than one cause is present, each sufficient alone (two gunshots each lethal).
- **Joint causation** — multiple causes are all necessary; none redundant. **Mackie's INUS** conditions: a cause is an *Insufficient but Necessary part of an Unnecessary but Sufficient* condition.
- **Mutual manifestation partners** (C.B. Martin) — a cause needs partners to do its work; a burning cigarette cannot ignite a fire without something flammable and oxygen.

**Context is the carrier of causal identity**: heating causes boiling, melting, burning, fever, drought, growth, ripening, explosion — depending on what else is present. Isolating a factor from its context can therefore erase its causal role rather than reveal it.

This lecture is a direct challenge to RCT methodology, which tests *one* causal factor at a time on the assumption that context-stripping reveals genuine causal contributions.

## Connections
Back-link: [[sources/2023-anjum-rocca-phi403-causation-in-science]]. Concepts: [[concepts/dispositionalism]] · [[concepts/rct-limitations]] · [[concepts/causation]].