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Logical Fallacies
A fallacy is an error in logic – a place where someone has made
a mistake in their thinking. Sometimes the errors occur because
the writer/speaker is avoiding the question, or making an
assumption, using a statistical fallacy or using propaganda as a
way to make their argument.
Avoiding the Question:
Red Herring: a red herring introduces an irrelevant point into an argument. Someone may
think (or may want us to think) it proves his side, but it really doesn’t.
Special Pleading: When someone uses a double standard or argues for an unjustified
exception, he is committing the fallacy of special pleading.
Ad Hominem: An Ad Hominem attack is attacking an opponent’s character or his motives for
believing something, instead of disproving his argument.
Genetic Fallacy: The genetic fallacy is condemning an argument because of where it began,
how it began or who began it.
Tu Quoque: Latin for “you too”. Tu quoque is dismissing someone’s viewpoint on an issue
because he himself is inconsistent with that very thing.
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Ad Populum – Appeal to the People: When we claim that our viewpoint is correct because
many other people agree with it, we are committing the appeal to the people fallacy.
Straw Man: The fallacy of Straw Man is changing or exaggerating an opponent’s position to
make it easier to refute.
Making Assumptions:
Circular Reasoning: An argument in which “P is true because Q is true, and Q is true because
P is true” is using circular reasoning.
Equivocation: An equivocation changes the meaning of a word in the middle of an argument.
Loaded Question: When someone asks two questions, but one is hidden behind the other,
that’s a loaded question.
Slippery Slope: The slippery
slope fallacy assumes that if we
take one step, nothing will stop us
from taking a series of steps
because each step is the same.
Part-to-Whole: When
someone says that what is
true of part of something must
also be true of the whole thing
together, he is using the partto-whole fallacy
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Whole-to-part: When someone says that what is true of something as a whole must also be
true of its parts, then that person is using whole-to-part fallacy.
Either-or: When someone asserts that we must choose between two things, when in fact we
have more than two alternatives, he is using the either-or fallacy.
Statistical Fallacies:
Generalizations: When you examine one or more of the people or things in a class, then you
are taking a sample of that class. A generalization takes a sample from a class of things, then,
using the characteristics of that sample, says something about everything in that class.
Generalizations can be either strong or weak.
Hasty Generalization: A hasty generalization is generalizing about a class based upon a small
or poor sample.
Analogy: We are reasoning by analogy when we compare two or more items with each other.
We notice that these items are the same in one or more ways and conclude that they will be the
same in other ways also.
Weak Analogy: If the similarities between the items being compared are major and the
differences only minor, then the analogy is a strong analogy. If the differences between the
items being compared are major and the similarities are minor, then we call that a weak
analogy. The fallacy of weak analogy claims that some items with only minor similarities are
the same in almost everything else.
Post Hoc Ergo Propter
Hoc (Latin for “after this,
therefore because of this”)
Post hoc ergo proper hoc is
concluding that since A
happened before B, A must
have caused B
Proof by lack of evidence: The proof by lack of evidence fallacy is claiming something is true
simply because nobody has yet given any evidence to the contrary.
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Propaganda
Propaganda is any strategy
for spreading our beliefs or
ideas.
Appeal to Fear: Appeal to fear is a propaganda
technique that is used when someone makes you
fear the consequences of not doing what he wants.
Appeal to Pity: When someone tries to make us
do something only because we pity him or we pity
something associated with him, then he is using
the propaganda technique called appeal to pity.
Exigency: Exigency is being used when nothing
more than a time limit is being given as a reason
for us to do what someone wants.
Repetition: Repetition is repeating a message loudly and very often in the hope that we will
believe it.
Transfer: Transfer is getting us to transfer our good or bad feelings about one thing to another
unrelated thing.
Snob Appeal: Snob appeal is used when someone tries to make us think his product would
make us better or make us stand out from everyone else.
Appeal to Tradition: An appeal to tradition occurs when someone encourages us to buy some
product or take some action because it is associated with things of the past.
Appeal to Hi-Tech: In an appeal to hi-tech, we are encouraged to buy something because it is
the latest thing, not necessarily because it is the best thing.