Logical Fallacies
...and how to detect them
In order to understand what
a fallacy is, one must understand what an argument is.
Very briefly, an argument consists of one or more premises and one conclusion.
A premise is a statement (a sentence that is either true or false) that is
offered in support of the claim being made, which is the conclusion (which is
also a sentence that is either true or false).
Your assignment is this: Choose some of the
fallacies and figure out what they are and how they work. Write a brief description of the fallacies,
including their Latin names, and provide at least two examples. At least one of the examples you provide must
be of your own devising, and may be drawn from experience or your imagination.
You could also find examples in newspapers, magazines books, or on the
Internet, other than those I provide.
The links below provide examples.
Rubric
Number of fallacies: You can get up to
70% for one fallacy, up to 80% for two, up to 90% for 3 and up to 100% for four
fallacies.
Each fallacy will be marked out of
10 with marks for:
Examples: 4 marks for three or more examples, none from the pages I
gave you to start. 3
marks for two or three examples with at least one original. 2 marks for two original examples. 1 mark
for two unoriginal examples.
Clarity: 2 marks for a clear and understandable presentation. 1 if not.
Originality: 2 marks for a
presentation in your own words. 1 if not.
Completeness: 2 marks if you have the Latin and English names of the
fallacy and a full explanation. 1 If
parts missing.
Here are some places to
start. First you will find brief
definitions of the categories of fallacies and some particular examples from
that category listed by their English names.
The list below the first list is of particular fallacies, often with
their Latin names. By clicking on any of
the names you can go to more info:
Fallacies of Distraction
- False Dilemma:
two choices are given when in fact there are three options
- From Ignorance:
because something is not known to be true, it is assumed to be false
- Slippery Slope:
a series of increasingly unacceptable consequences is drawn
- Complex Question:
two unrelated points are conjoined as a single proposition
Appeals to Motives in Place of Support
Changing the Subject
- Attacking the Person:
- (1) the person's
character is attacked
- (2) the person's
circumstances are noted
- (3) the person does
not practise what is preached
- Appeal to Authority:
- (1) the authority is
not an expert in the field
- (2) experts in the
field disagree
- (3) the authority was
joking, drunk, or in some other way not being serious
- Anonymous Authority:
the authority in question is not named
- Style Over Substance:
the manner in which an argument (or arguer) is presented is felt to affect
the truth of the conclusion
Inductive Fallacies
There is reason to
question even the well-constructed inductive argument. I am including this here for
completeness. Beware that these are
inductive rather than deductive arguments
- Hasty Generalization:
the sample is too small to support an inductive generalization about a
population
- Unrepresentative Sample:
the sample is unrepresentative of the sample as a whole
- False Analogy:
the two objects or events being compared are relevantly dissimilar
- Slothful Induction:
the conclusion of a strong inductive argument is denied despite the
evidence to the contrary
- Fallacy of Exclusion:
evidence which would change the outcome of an inductive argument is
excluded from consideration
Fallacies Involving Statistical Syllogisms
- Accident: a
generalization is applied when circumstances suggest that there should be
an exception
- Converse Accident :
an exception is applied in circumstances where a generalization should
apply
Causal Fallacies
- Post Hoc:
because one thing follows another, it is held to cause the other
- Joint effect:
one thing is held to cause another when in fact they are both the joint
effects of an underlying cause
- Insignificant:
one thing is held to cause another, and it does, but it is insignificant
compared to other causes of the effect
- Wrong Direction:
the direction between cause and effect is reversed
- Complex Cause:
the cause identified is only a part of the entire cause of the effect
Missing the Point
- Begging the Question:
the truth of the conclusion is assumed by the premises
- Irrelevant Conclusion:
an argument in defense of one conclusion instead proves a different
conclusion
- Straw Man:
the author attacks an argument different from (and weaker than) the
opposition's best argument
Fallacies of Ambiguity
- Equivocation:
the same term is used with two different meanings
- Amphiboly:
the structure of a sentence allows two different interpretations
- Accent: the
emphasis on a word or phrase suggests a meaning contrary to what the
sentence actually says
Category Errors
- Composition:
because the attributes of the parts of a whole have a certain property, it
is argued that the whole has that property
- Division:
because the whole has a certain property, it is argued that the parts have
that property
Non Sequitur
Syllogistic Errors
Fallacies of Explanation
- Subverted Support
(The phenomenon being explained doesn't exist)
- Non-support
(Evidence for the phenomenon being explained is biased)
- Untestability
(The theory which explains cannot be tested)
- Limited Scope
(The theory which explains can only explain one thing)
- Limited Depth
(The theory which explains does not appeal to underlying causes)
Fallacies of Definition
- Too Broad
(The definition includes items which should not be included)
- Too Narrow
(The definition does not include all the items which shouls
be included)
- Failure to
Elucidate (The definition is more difficult to
understand than the word or concept being defined)
- Circular Definition
(The definition includes the term being defined as a part of the
definition)
- Conflicting
Conditions (The definition is self-contradictory)
The List
Click on the fallacy name to go to a full explanation with
examples, or go here
where the major ones have all been put onto one page.