Fallacy of the Single Cause
Causal Oversimplification · Causal Reductionism · Complex Cause
Assuming that there is one, simple cause of an outcome when in reality it may be caused by a number of only jointly sufficient causes.
Origin
The recognition that events rarely have a single cause dates to Aristotle's four types of causation in the 4th century BCE. John Stuart Mill advanced the critique in the 19th century through his methods of induction, designed to isolate causes systematically. The fallacy was formalized as a named informal error in 20th-century logic textbooks — notably Irving Copi's Introduction to Logic (1953), which categorized causal oversimplification under "false cause" reasoning.
Everyday Use
"The economy crashed because of [single policy/person]." "I got sick because I forgot my jacket." Reality is messy — most outcomes have multiple, interacting causes. Pinning everything on one factor feels satisfying but usually misses the real picture and leads to bad fixes.