Hasty generalization: Conclusion not logically justified by sufficient or unbiased evidence.
Post hoc ergo propter hoc: Literally, “after this, therefore because of this.” Just because Event B occurred after Event A does not mean that A necessarily caused B.
Genetic fallacy: Arguing that the origins of a person, object, or institution determine its character, nature, or worth. Like the post hoc fallacy, the genetic fallacy is an error in causal relationships.
Begging the question: Loading the conclusion in the claim. Arguing that “pornography should be banned because it corrupts our youth” is a logical claim. However, saying that “filthy and corrupting pornography should be banned is begging the question: The conclusion that the writer should prove (that pornography corrupts) is assumed in the claim.
Circular argument: A sentence or argument that restates rather than proves.
Either/or: An oversimplification that reduces alternatives to only two choices, thereby creating a false dilemma. Statements such as “Love it or leave it” attempt to reduce the alternatives to two. If you don’t love your school, your town, or your country, you don’t have to leave: A third choice is to change it and make it better. Proposed solutions frequently have an either/or fallacy.
Faulty comparison or analogy: Basing an argument on a comparison of two things, ideas, events, or situations that are similar but not identical. Although comparisons or analogies are often effective in argument, they can hide logical problems. The point is not to avoid comparisons or analogies. Simply make sure that your conclusions are qualified; acknowledge the differences between the two things compared as a well as the similarities.
Ad hominem (literally, “to the man”): An attack on the character of the individual or the opponent rather than his or her actual opinions, arguments, or qualifications.
Ad populum (literally, “to the people”): An emotional appeal to positive concepts (God, mother, country, liberty, democracy, apple pie) or negative concepts (fascism, treason, atheism) rather than a direct discussion of the real issue.
Red herring and straw man: Diversionary tactics designed to avoid confronting the key issue. Red herring refers to the practice of dragging a smelly fish across the trail to divert tracking dogs away from the real quarry. A red herring occurs when writers avoid countering an opposing argument directly. In the straw man diversion, the writer sets up an artificially easy argument to refute in place of the real issue. Avoid red herring and straw man tactics by either refuting an argument directly or acknowledging that it has some merit.