Undistributed middle

What it is

Concludes that two categories overlap because both overlap with a third: "All A are C; all B are C; therefore all A are B".

Related

• Representativeness heuristic bias
  Believing two groups overlap because they share a trait is judging by resemblance.
• Belief bias bias
  Invalid syllogisms feel valid when the conclusion fits what we believe.

References

• Wikipedia: Undistributed middle en.wikipedia.org
• Internet Encyclopedia of Philosophy: Fallacies iep.utm.edu
• Stanford Encyclopedia of Philosophy: Fallacies plato.stanford.edu
• Wikipedia: List of fallacies en.wikipedia.org
• Purdue OWL: Logical fallacies owl.purdue.edu

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