§   DEFINITION      

Only Reason – identifying one valid reason, but ignoring the other possible reasons.
 

Writers who state that there is only one reason for an occurrence, while ignoring the possibility of the existence of others, commit the only reason fallacy.  No complex phenomenon can be reduced to one single simple cause.   There must be other explanations, other reasons to explain an event caused by so many influences.
 

EXAMPLE 1

A political activist says: “Poverty causes crime.”

This statement is an example of oversimplifying the cause that generates an effect.  Poverty alone cannot be the sole cause of crime.  We know this because not every poor person commits a crime; in fact, our biggest crime problem in terms of dollars in the USA is white-collar crime (creative accounting, insurance fraud, money laundering, phone card scams, etc.).  Poverty is one of the most direct causes of crime, and actually one of the easiest to solve.

 
EXAMPLE 2

A history student might oversimplify its causes and effects: “The American Revolution was a revolt against the heavy tax imposed by Great Britain on imported tea.”

Although the famous Boston Tea Party sent a clear message to England, Americans were frustrated with hundreds of other special taxes against their colonies, not to mention biased courts, no local control of the armies, prejudiced immigration laws, and religious tensions.  To state that there is a “one and only” cause to such a complex historical movement blinds the reader to the bigger picture, while giving more credit to the only reason mentioned than it deserves.