Identifying Illogical Arguments
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These are names and explanations of some common logical fallacies to keep an eye out for both in your own writing and in any reading that you might be doing.
Common Logical Fallacies
Ad Hominem
Attacking the author of ideas does not imply that his/her argument is flawed. If you think an argument is flawed, then don’t attack the author—attack his/her ideas!
Appeal to Authority
Always remember, the authorities might be wrong.
Appeal to Ignorance
This is the claim that just because something has never been proven, it cannot be proven, or in other words, that something is false.
Bandwagon Appeal
Also remember, the majority might be wrong. Appealing to common practice or common assumptions can neither prove the moral worth of a behavior nor the logical soundness of an argument.
Begging the Question/Circular Argument
To beg the question is to assume that which you are trying to prove. When prompted to give support, the author simply begs off and restates the conclusion.
Composition
The fallacy of composition is committed when the conclusion of an argument depends on the erroneous transference of an attribute from the parts of something to the whole.
Correlation, Not Causation
Two things that occur together might not be causally related; they might be joint effects of the same cause or, then again, they might be totally unrelated.
Division
The fallacy of division is the opposite of composition: it is the erroneous transfer of a property from the whole of something to the parts.
Equivocation
If an argument relies on two different meanings of a word to make its point, then it is invalid.
False Analogy
To argue from analogy is to transfer properties of one thing to something else that is similar. Sometimes the argument that the second thing has the same properties is appropriate, but sometimes it is not.
Hasty Generalization
In order to make a generalization from the consideration of particulars, you must have adequate evidence, including enough observations of the particular instance as well as observations that relate to different relevant situations.
Is – Ought Problem
It is difficult, perhaps impossible, to make an argument about the way things should be by looking solely at evidence about the way that they, in fact, are. Nothing is either right or wrong simply because it occurs.
Neglected Alternative/False Dichotomy
In arguing that something is not one thing, and so it must be another, you must show that the two things predicated are opposites and that there are no other possibilities. You cannot ignore possible compromises or other alternatives.
Non Sequitur
An argument introduces a non sequitur if the premises are not logically connected or if the conclusion does not logically follow from the premises.
Post Hoc, Ergo Proper Hoc
Just because an action or event precedes another event does not mean that something is the cause of that event.
Red Herring
The red herring was once used to train hunting dogs to follow scents. An author is using a “red herring” when s/he presents evidence that it not relevant to her/his conclusion— effectively. distracting her/his audience by throwing them off track.
Simple Cause/Complex Effect
When you reduce a complex phenomenon to a single and simple cause, you will always be wrong.
Slanted Language
In this case, an author might use a particularly charged word to make his/her point. If you use a word that does not have a negative connotation, check to make sure the argument works.
Slippery Slope
An argument might insist that there is a slippery slope from one thing to something else that is “obviously” bad. Yet, simply because an extreme degree of something is bad, that doesn’t necessarily mean a small amount is unacceptable and will lead to an extreme and “bad” amount.
Stacked Evidence
An author might try to convince his/her reader by presenting evidence for only one side of an issue. However, a conclusion cannot be proven successfully unless relevant counter-arguments have been refuted.
Straw Man
You must base your criticisms of an opponent’s position on a fair and generous understanding of his/her argument.
Two Wrongs Make a Right
This is when an author tries to justify an unethical action by pointing to other unethical actions that persist and/or go unpunished.
Last revised: 07/2008 | Adapted for web delivery: 03/2021
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