1. Hasty or Sweeping Generalization:
Absolute situations are rare. Reality is in degrees.
Avoid:
 | "Everyone has fond memories of high school." |
| "Men are better at sports than women." |
| "All advertising is lies." |
| Be careful with terms like
"all," "always," "everybody,"
"nobody," or "none". |
|
2. False Extremes...
Either/Or Position:
|
Don't reduce a complex issue to only two possibilities. |
|
Things are seldom black or white. eg. "The department must either raise its grading standards
or bury forever the ideal of academic excellence." |
| This is misleading because it ignores the
existence of other less extreme possibilities. |
|
3. Straw Man:
|
A straw man argument occurs when you misrepresent an opposing view to make it seem
weaker than it is. |
| "Opposition to nuclear weapons testing in Canada is simple
anti-Americanism." |
|
4. Circular Reasoning/Vicious circle:
|
This error occurs when a person restates a generalization as a reason for accepting
the same proposition. |
| "Exercise is healthy because your body needs
exercise." |
| "The play was popular because the audience liked it" |
|
5. Post Hoc Arguments/Unfounded assumption of cause:
|
This error occurs when a person assumes that because one thing followed another thing the
first item caused the second item, or Since 'B' followed 'A', 'A' caused 'B'. |
| e.g. "I broke my leg
because it was Friday the 13th." |
| "Some students who work part-time fail a course; therefore,
working part-time causes students to fail." |
| These are not logical consequences. |
|
6. Two Wrongs
don't make a right:
| A bad action is not justified by another wrong action. |
| eg. "That chemical company pollutes the
river; therefore, we were right to blow it up." |
| "He was a creep, so I will be a creep too." |
|
7. False Analogies:
| Analogies may make strong emotional appeals, but their logic may be weak. |
| Analogy is effective only
when there is a basic similarity between compared terms. |
| eg. "University administration argues
for new rules, because it should be run like a business." |
| But a University is not equal to a
business. |
|
8. Prediction of Consequences:
|
Be careful when predicting that an act will have positive or negative consequences. |
| eg. 'If you
take our course, you too will become rich." |
|
9. False Assumptions:
|
One false assumption can cause all of your arguments following to be invalid. |
| eg. "Without
advertising, no cities could exist." |
|
10. Out of Context
Citation:
|
Beware or incomplete quotations. |
| eg. The critic said, "Most of the movie was unbelievably bad,
but there were a few moments of high comedy." The ad for the movie,
published the next day, read, "High Comedy...The Toronto Star." |
| Watch also for misuse of statistics, skewed samples, and anecdotal information. |
|
11. Non Sequitur (It does not follow):
| If a famous actress uses Crest toothpaste, that has no relation to the quality of the
toothpaste. |
| eg. "A man does not beat his wife; therefore, he is a good husband." |
|
12. False Appeal
to Authority:
| An illegitimate appeal to
authority. |
| First, the authority or reference
may be ambiguous. Appeal is made to the Bible by both those
who support and those who oppose capital punishment, and by both
those who castigate and those who advocate help for the poor. |
| Second, the authority may be
irrelevant to the problem. The fact that a man is a first
rate physicist does not mean that he can speak with legitimate
authority about race relations. |
| Third, the authority may be
pursuing a bias rather than studying a problem. |
|
13. Begging the Question:
|
When you beg the question, you assume the truth of what needs to be proven. |
| eg. A politician
says, "Our feeble government, greatly in need of reform must be placed in new hands." |
| eg. A
student challenges a "C" grade on the grounds that she is an "A" student. |
| The premise in both
of these is what is under question |
|
14. Ignoring the Question:
|
Sometimes in arguing, people raise irrelevant points that distract from the real issue. |
| Red Herring... eg. A government defends itself on a charge of corruption by saying that
the budget is balanced. |
| Attack The Man/Woman... eg. "I'm a liar...so are you." |
| "I'm a crook...well, you're a
racist" |
|
15. Stereotypes:
Watch out for any stereotypes.
| Making generalizations of any
kind about groups of people are based on two further fallacies: |
| The Fallacy of Composition:
assuming that what is true for a small portion of a group is also
true for the whole. |
| The Fallacy of Dramatic Instance:
taking a small observation about a small sub-category of people
and inflating it into a large, sweeping assumption and ongoing
narrative about all people of the larger group to which that
sub-group belongs. |
| This is how racism, classism, and
sexism begin... |
|
16. Argument to ignorance:
Watch out for these types of claims:
| It must be true it hasn't been proven false. |
| It must be false, it hasn't been proven true. |
|
17. Gambler's Fallacy:
| "It hasn't happened for a long time;
therefore it's bound to happen." |
| "It keeps
happening; therefore, it will keep happening." |
|
