What is a logical fallacy?

Logical Fallacies
What is a logical fallacy?
A logical fallacy is, at its essence, an error of reasoning. When an argument is used, based
on bad reasoning to support a position (or to try to convince someone to adopt the same
position), it is considered a fallacy.
Appeal to Antiquity or Tradition
Appeal to Common Belief
Appeal to Consequences
Appeal to Nature
Appeal to Novelty
Argument from Fallacy
Argument from False or Misleading Authority
Argument from Ignorance
Argumentum Ad Hominem
Bandwagon Fallacy
Cherry Picking or Quote Mining
Confirmation Bias
Fallacy of Composition
False Dichotomy
False Equivalence
Fallacy of Division
Fundamental Attribution Error (or Correspondence Bias)
Gallileo Gambit
Gambler's Fallacy
Genetic Fallacy
Gish Gallop
Naturalistic Fallacy
Nirvana Fallacy
Non Sequitur
Poisoning the Well
Post hoc ergo propter hoc
Shill Gambit
Slippery Slope Fallacy
Special Pleading
Strawman Argument
Appeal to Antiquity or Tradition
Description
Appeal to antiquity is a common logical fallacy that occurs when it is assumed that
something is better or correct simply because it is older, traditional, or “always has
been done.”
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Example
Homeopathy has been around 200 years, so obviously it must work.
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Appeal to Common Belief
Description
Also known as the Argumentum ad populum, it is the claim that most or many people
in general or of a particular group accept a belief as true is presented as evidence for
the claim. Accepting another person’s belief, or many people’s beliefs, without
demanding evidence as to why that person accepts the belief, is lazy thinking and a
dangerous way to accept information.
This is used by many anti-science arguments by stating that because 90% of
Americans believe that X is true, then X must surely be true.
Example
Over 60% of Americans believe creationism is true, so evolution must be false.
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Appeal to Consequences
Description
Appeal to consequences is an attempt to motivate belief with an appeal either to the
good consequences of believing or the bad consequences of disbelieving, without
respect to the quality of the evidence supporting such an argument. Of course, there
may be consequences to a belief, as long as it is supported by evidence.
Example
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Belief in evolution will lead to mass genocide.
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Appeal to Nature
Description
Appeal to Nature, similar to the naturalistic fallacy, when used as a fallacy, is the
belief or suggestion that “natural” is always better than “unnatural”. It assumes that
"nature" is good, and "unnatural" is not. Unfortunately, in many discussions about
science and medicine, individuals take this as their default belief.
Example
High fructose corn syrup is not natural so it must be bad for you.
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Appeal to Novelty
Description
Appeal to Novelty, the opposite of the Appeal to Antiquity, is an argument that the
novelty or newness of an idea is itself evidence of its truth. Since every rejected idea
in the history of man was once a "novel idea", the fallaciousness of this argument is
apparent.
Example
If you want to lose weight, your best bet is to follow the latest diet..
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Argument from Fallacy
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Logical Fallacies
Description
The Fallacist’s Fallacy, also known as argument to logic (argumentum ad logicam),
fallacy fallacy, or fallacist's fallacy, is dismissing a proposition because on of its
supporting arguments contains a logical fallacy. In other words, the rejection of an
idea as false simply because the argument used to support the idea is itself
fallacious. Just because one argument lacks merit or is fallacious, that it is not
sufficient evidence to reject the idea.
Example
Tom: OK — I'll prove I'm English — I speak English so that proves it.
Bill: But Americans and Canadians, among others, speak English too. You are
assuming that speaking English and being English always go together. That means
you are not English..
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Argument from False or Misleading Authority
Description
Argument from false or misleading authority, or argumentum ad vericundiam, is a
logical fallacy which provides an argument from an authority, but on a topic outside of
the particular authority's expertise or on a topic on which the authority is not
disinterested (i.e., is biased).
Almost any subject has an authority on every side of the argument, even where there
is generally agreed to be no argument. When correctly applied, it can be a valid and
sometimes essential part of an argument that requests judgement or input from a
qualified or expert source. The works (almost always published and peer-reviewed)
of authorities, no matter how eminent or influential, is always judged by the quality of
their evidence and reasoning, not by their authority alone.
Example
Dr. Smith, an expert in computer engineering, does not believe in climate change, so
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obviously climate change is false.
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Argument from Ignorance
Description
Argument from ignorance infers that a proposition is true from the fact that it is not
proven to be false (or alternatively, that a proposition is false because it is not proven
to be true). The old argument that "the absence of evidence is not evidence of
absence" is a form of this logical fallacy, because absence of evidence can be
evidence of absence if substantial attempts to find evidence have proven negative.
The fallacy also asserts that a proposition is true because it has not yet been proven
false, or it is "generally accepted" (or vice versa).
Furthermore, this argument presumes that there are only two choices: true or false.
In fact, there are other choices, including "not enough investigation has been
completed to choose between true or false." So a non-fallacious argument may be
made that a proposition is not false because insufficient testing has been done to
show it false. That is a reasonable argument.
Appeals to ignorance are used to shift the burden of proof to the other side. However,
the burden of proof should be on the side that is making the assertion, not on the
side that disputes the assertion.
Example
There is no evidence that says a god doesn't exist, so a god must exist.
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Argumentum Ad Hominem
Description
The Argumentum ad hominem, or simply ad hominem argument, applies to any
argument that centers on emotional (specifically irrelevant emotions) rather than
rational or logical appeal. An ad hominem argument occurs when one attacks the
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person making an argument rather than the argument itself.
Example
You're a shill for Big Pharma so any of your statements about vaccine safety can't be
trusted because Big Pharma is paying you off.
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Bandwagon Fallacy
Description
The Bandwagon Fallacy is committed by an argument that appeals to the growing
popularity of an idea. This popularity is used as the reason for accepting it as true.
Such an argument is fallacious because popularity may not arise from an actual fact,
but may result from peer pressure, political expediency, or even plain mass stupidity.
Popularity does not guarantee the truthfulness of an argument.
Example
Creationism is supported by most Americans, so it must be true.
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Cherry Picking or Quote Mining
Description
Cherry picking is a fallacy where only select evidence is presented in order to
persuade the audience to accept a position, and evidence that would go against the
position is withheld. The stronger the the withheld evidence, the more fallacious the
argument. Quote mining is a form of cherry picking, and the genuine points used in
construction of straw man arguments are typically cherry-picked.
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Logical Fallacies
Example
You should be a Christian, because God is all about love and forgiveness, and those
are great things.
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Confirmation Bias
Description
Confirmation Bias is simply the tendency for individuals to favor information or data
that support their beliefs. It is the tendency for people to only seek out information
that conforms to their pre-existing view points, and subsequently ignore information
that goes against them. It is a type of cognitive bias and a form of selection bias
toward confirmation of the hypothesis under study. Avoiding confirmation bias is an
important part of rationalism and in science in general. This is achieved by setting up
problems so that you must find ways of disproving your hypothesis (see falsifiability).
Example
Psychic "readings" is that listeners apply a confirmation bias which fits the psychic's
statements to their own lives. By making a large number of ambiguous statements in
each sitting, the psychic gives the client more opportunities to find a match. This is
one of the techniques of cold reading, with which a psychic can deliver a subjectively
impressive reading without any prior information about the client.
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Fallacy of Composition
Description
The Fallacy of Composition is an incorrect inference that the qualities of the whole
can be made from the qualities of one of its parts. It is the opposite of the Fallacy of
Division.
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Logical Fallacies
Example
Human cells are invisible to the naked eye.
Humans are made up of human cells.
Therefore, humans are invisible to the naked eye.
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False Dichotomy
Description
A False Dichotomy, or false dilemma, is a dichotomy (a set of two mutually
exclusive, jointly exhaustive alternatives) of arguments that ignores the potential
for an infinite set of alternative arguments; for an infinite number of overlapping
arguments; or for the potential that neither part of the dichotomy is correct. A false
dichotomy is often employed by an arguer to force the other side into an extreme
position by assuming that there are only two possible positions. At it's essence, it
says "you are either with us or against us," which ignores the all other
possibilities, such as "we are with you on points A&B, but against you on points
C,D&E."
Example
Because evolution has not been unable to show exactly how life arose, evolution is
therefore disproved, and creationism is obviously the correct answer.
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False Equivalence
Description
False equivalence is a logical fallacy where there appears to be a logical equivalence
between two opposing arguments, but when in fact there is none. Journalists use a
form of this logical fallacy when comparing two sides of a scientific debate in an
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attempt to provide a balance between a scientific and denialist point of view.
However, there is no equivalence between the two sides, when one is supported by
evidence, and the other side with little or no evidence, of which most is of low quality.
In other words, in false equivalence, someone will state that the opposing arguments
have a passing similarity in support, when, on close examination, there is large
difference between the quality of evidence
Example
Marijuana and alcohol are both drugs. An ounce is about the same as three bottles. If
you think one should be legal, you should think the same of the other.
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Fallacy of Division
Description
The Fallacy of Division is an incorrect inference that the qualities of the parts can be
deduced from the characteristics of the whole. It is the opposite of the Fallacy of
Composition.
Example
Humans are visible to the naked eye.
Humans are made up of human cells.
Therefore, human cells are visible to the naked eye.
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Fundamental Attribution Error (or Correspondence Bias)
Description
The fundamental attribution error (also known as correspondence bias or
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attribution effect) describes the tendency to over-value dispositional or
personality-based explanations for the observed behaviors of others while
under-valuing situational explanations for those behaviors. The fundamental
attribution error is most visible when people explain the behavior of others.
It does not explain interpretations of one's own behavior—where situational
factors are often taken into consideration. Fundamental attribution error is a
social/psychological bias, is not a true logical fallacy. However, it is
frequently used in arguments or debates.
Example
As a simple example, if Alice saw Bob trip over a rock and fall, Alice might consider
Bob to be clumsy or careless (dispositional). If Alice tripped over the same rock
herself, she would be more likely to blame the placement of the rock (situational).
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Gallileo Gambit
Description
The Galileo Gambit is a fallacy where the putative expert insists that he is an
unacknowledged genius, a maverick who is shunned by mainstream science
because of his unconventional ideas.
Example
I am an expert in vaccines, because I have a Masters of Public Health, but my
brilliant and radical ideas have been rejected by mainstream medicine because Big
Pharma and the CDC are suppressing my ideas because my knowledge will disrupt
all of our knowledge about vaccines.
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Gambler's Fallacy
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Logical Fallacies
Description
The Gambler’s Fallacy is the fallacy of assuming that a short-term deviation from
statistical probability will be corrected in the short-term. In a totally random event,
past performance has no effect on the next attempt. Arguing that a totally random
event may have a result that will self-correct the "average" is fallacious. is the false
belief that a random process becomes less random, and more predictable, as it is
repeated. This is most commonly seen in gambling, hence the name of the fallacy.
For example, a person playing craps may feel that the dice are "due" for a certain
number, based on their failure to win after multiple rolls. This is a false belief as the
odds of rolling a certain number are the same for each roll, independent of previous
or future rolls.
Example
1.
2.
This coin has landed heads-up nine times in a row. Therefore,
It will probably land tails-up next time it is tossed.
This inference is an example of the gambler’s fallacy. When a fair coin is tossed, the
probability of it landing heads-up is 50%, and the probability of it landing tails-up is
50%. These probabilities are unaffected by the results of previous tosses.The
gambler’s fallacy appears to be a reasonable way of thinking because we know that
a coin tossed ten times is very unlikely to land heads-up every time. If we observe a
tossed coin landing heads-up nine times in a row we therefore infer that the unlikely
sequence will not be continued, that next time the coin will land tails-up. In fact,
though, the probability of the coin landing heads-up on the tenth toss is exactly the
same as it was on the first toss. Past results don’t bear on what will happen next.
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Genetic Fallacy
Description
This Genetic Fallacy creates an argument that is accepted or rejected based on the
source of the evidence, rather than on the quality or applicability of the evidence. It is
also a line of reasoning in which a perceived defect in the origin of a claim or thing is
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taken to be evidence that discredits the claim or thing itself.
Example
He has a medical degree and doesn't like vaccines, so obviously vaccines are bad.
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Gish Gallop
Description
The Gish Gallop occurs when the putative expert slickly rattles off a long list of
assertions without providing evidence or allowing questions.
Example
And just because YOU don’t know how the cheese is created on the moon, doesn’t
mean that there isn’t a cheese creating mechanism at the core of the moon. Run by
secret moon wizards. And there are moon cows, that only live on the far side of the
moon, eating moon grass that grows during the 14.25 days of the month where it’s
illuminated – presumably spending the remaining 14.25 days in hibernation or
possibly storing metabolite like cacti. Naturally, since the crust is mostly rock, then
the grass would be mostly rock too, leading to heavier milk and cheese. There’s
your Occam’s Razor! All you need to do is assume the existence of a completely
novel form of biological life and the explanation becomes simple! Even more so
when this neatly explains the motivation for Big Milk – moon cheese is much more
valuable than “earther cheese” and only the superwealthy can afford the biological
processing necessary to make it edible instead of poisonous which is why only the
super-rich members of the Illuminati and Freemasons know about it. NOW IT ALL
MAKES SENSE!!!!!
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Naturalistic Fallacy
Description
The Naturalistic Fallacy is similar to the appeal to nature, where the conclusion
expresses what ought to be, based only on actually what is more natural. This is
very common and most people never see the problem with these kind of assertions
due to accepted social and moral norms. This bypasses reason and we fail to ask
why something that is, ought to be that way.
Example
Homosexuality is morally wrong because in nature, sex is used for reproduction.
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Nirvana Fallacy
Description
The Nirvana Fallacy is an attempt to compare a realistic solution with an idealized
one, and dismissing or even discounting the realistic solution as a result of
comparing to a “perfect world” or impossible standard. This reasoning ignores the
fact that improvements are often good enough.
Example
What’s the point of making drinking illegal under the age of 21? Kids still manage to
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get alcohol.
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Non Sequitur
Description
Non Sequitur is the Latin phrase for "(it) does not follow."It means that the
conclusion reached does not follow from the premise(s). Examples of ''non
sequitur'' arguments are hilariously disconnected, but often they can be subtle and
may not be easily uncovered. The arguments are fallacious since they do not
provide any evidence for an argument and are just meant to confuse the listener.
Example
Homeopathy comes in pretty bottles. Therefore, homeopathy can cure cancer.
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Poisoning the Well
Description
To Poison the Well means to pre-provide any information that could produce a
biased opinion of the reasoning, positive or negative. It is related to the ad
hominem argument.
Example
Remember, Big Pharma supports vaccines, so any research that supports vaccines
should be examined carefully.
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Post hoc ergo propter hoc
Description
Also known as the post hoc, Post hoc ergo propter hoc is a Latin phrase, literally
translated as "after this, therefore because of this." It is a fallacious argument that
states that because a second event follows the first, the first event must be the cause
of the second. Many superstitions are based on this type of argument, because the
observer may notice that performing one action seems to lead to another.
Although post hoc observations may lead to a testable hypothesis, there must be
evidence of a mechanism that extends the correlation to causation.
Example
My child broke her leg after she was vaccinated, so vaccines cause broken legs.
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Shill Gambit
Description
The Shill Gambit is a type of ad hominem and poisoning the well, wherein one party
dismisses the other's argument by proclaiming them to be on the payroll of some
company. Sometimes known as the Big Pharma Shill Gambit or the Monsanto Shill
Gambit. The shill gambit is used fallaciously when the only "evidence" given of such
a connection to a big company or government is the endorsement of the position of
the government or company, without any other evidence–the implication is that they
provide that endorsement only because they receive some sort of compensation from
the company or other agency.
On the other hand when such conflict of interest is both demonstrated by verifiable
evidence and can be shown to interfere with a person's judgement of the evidence,
then it's no longer a logical fallacy.
Example
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The writer is only endorsing the safety and effectiveness of vaccines because he's
secretly paid by Big Pharma.
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Slippery Slope Fallacy
Description
Slippery Slope Fallacies are arguments that utilize the false assumption that once a
first step is taken, it predicts the next step, which then leads to the next step until
some conclusion is reached that supports the initial idea. The arguer then concludes
that we therefore shouldn’t do the first thing. There are several issues with this type
of fallacy, specifically, it makes a prediction that simply cannot be proven. It also
assumes that there isn't a restraint placed on subsequent steps that modify the
conclusion.
Example
If you teach evolution in school, you start down the slippery slope to immorality.
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Special Pleading
Description
Special pleading is a form of spurious argumentation where a position in a dispute
introduces favorable details or excludes unfavorable details by alleging a need to
apply special considerations or exemptions from typical analysis. These
considerations or exemptions are pushed into the argument without proper criticism.
Essentially, this involves someone attempting to cite something as an exemption to a
generally accepted rule, principle, etc. without justifying the exemption.
This fallacious argument is one of the most used in alternative medicine and other
pseudoscientific areas, since, lacking any scientific evidence, they attempt to excuse
the lack of evidence not because of implausibility, but because we lack the abilities to
understand their special mechanism. Often, you will here the phrase, "mainstream
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science just hasn't uncovered the mechanism yet."
Example
Homeopathy cannot be tested with modern science because we do not have a
proper understanding of its mechanisms.
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Strawman Argument
Description
A Strawman Argument, or simply strawman, is an argument that misrepresents a
position of the other side, in order to make it appear weaker than it actually is. The
arguer then refutes the arguer's misrepresentation of the position, leading others to
conclude that the real position has been refuted.
It is an intentional misrepresentation of an opponent's position, often used in debates
with unsophisticated audiences to make it appear that the opponent's arguments are
more easily defeated than they are. This is a fallacy, of course, because it has done
nothing to actually refute the position of the other side of the argument, nor provide
any evidentiary support of either side of the argument.
Example
The pro-vaccination doctors do not care about our autistic children, so vaccines are
bad.
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