Causal Fallacies

It is common for arguments to conclude that one thing causes another. But the relation between cause and effect is a complex one. It is easy to make a mistake.

In general, we say that a cause C is the cause of an effect E if and only if:

  1. Generally, if C occurs, then E will occur, and
  2. Generally, if C does not occur, then E will not occur ether.
We say "generally" because there are always exceptions. For example, we say that striking the match causes the match to light, because:
  1. Generally, when the match is struck, it lights (except when the match is dunked in water), and
  2. Generally, when the match is not struck, it does not light (except when it is lit with a blowtorch).
Many writers also require that a causal statement be supported with a natural law. For example, the statement that "striking the match causes it to light" is supported by the principle that "friction produces heat, and heat produces fire". The following are causal fallacies:
  • Post Hoc (Because one thing follows another, it is held to cause the other)
  • Joint Effect (A purpoted causeand effect are both the effects of a joint cause)
  • Insignificant (The purported cause is insignificant compared to others)
  • Wrong Direction (The direction between cause and effect is reversed)
  • Complex Cause (The cause identified is only part of the entire cause)
06 October 1995