Logical Fallacies (common types of errors in reasoning):
Fallacies are broken down into two categories: formal and informal. Formal fallacies are based strictly on the logical formation of an argument (deductive). Informal fallacies, which are the most commonly recognized and easiest to learn, take into account the non-logical content of an argument (inductive); they are false for epistemological, dialectical or pragmatic reasons, and typically fall under three categories: relevance, presumption, and ambiguity. The first formation of logical fallacies comes to us from Sir Thomas Aquinas and “The Scholastics”.
Though liberal / leftist in its leaning, this list gives an excellent understanding of the core fallacies. Just look out for that “libertine fallacy”.
Copyright 1995 Michael C. Labossiere. If you have questions or comments about this work, please direct them both to Dr. Labossiere (firstname.lastname@example.org).
Other sites that list and explain fallacies include:
In order to understand what a fallacy is, one must understand what an
There are two main types of arguments: deductive and inductive. A
A fallacy is, very generally, an error in reasoning. This differs
- Inductive ArgumentPremise 1: Most American cats are domestic house cats.Premise 2: Bill is an American cat.
Conclusion: Bill is domestic house cat.
- Factual ErrorColumbus is the capital of the United States.
- Deductive FallacyPremise 1: If Portland is the capital of Maine, then it is in Maine.Premise 2: Portland is in Maine.
Conclusion: Portland is the capital of Maine.
(Portland is in Maine, but Augusta is the capital. Portland is the largest city in Maine, though.)
- Inductive FallacyPremise 1: Having just arrived in Ohio, I saw a white squirrel.Conclusion: All Ohio Squirrels are white.
(While there are many, many squirrels in Ohio, the white ones are very rare).