Logical Fallacies

Front 1

(FORMAL)
A causes B. B occurred, therefore A caused B.

Back 1

Affirming the consequent, or "Backwards logic"

Hint 1

Putting the cart before the horse

Front 2

(FORMAL)
The assertions used in an argument contradict the conclusion.

Back 2

Conclusion which denies premises

Hint 2

The "I forgot what I was talking about" fallacy

Front 3

(FORMAL)
Two or more assumptions in the argument are contradictory.

Back 3

Contradictory premises

Hint 3

"Everything is mortal, God is not mortal, God is not everything."

Front 4

(FORMAL)
Failure to admit the possibility that two different events can have the same result.

Back 4

Denying the antecedent

Hint 4

"If he's slow, he'll loose the race. Because he isn't slow, he won't loose the race."

Front 5

(FORMAL)
Nothing can be deduced from an argument with two negative premises.

Back 5

Exclusive premises

Hint 5

"No x are z, no y are z, so no x are y."

Front 6

(FORMAL)
Admitting, falsely, that a class of objects exists by referring to a subgroup of that class.

Back 6

The existential fallacy

Hint 6

"Some UFOs are from Mars"

Front 7

(FORMAL)
A false conversion between a "some are" statement and a "none are" statement.

Back 7

False conversion

Hint 7

"All cats are animals, therefore all animals are cats"

Front 8

(FORMAL)
"All x are y, all y are z. Therefore all x are z."

Back 8

Illicit Process (Minor)

Hint 8

All whales are mammals.
All mammals are animals.
Therefore, all animals are whales.

Front 9

(FORMAL)
"All x are y, no z are x. Therefore no z are y."

Back 9

Illicit Process (Major)

Hint 9

All communists are leftists.
No conservatives are communists. Therefore, no conservatives are leftists.

Front 10

(FORMAL)
Mismatching positive/negative premises/conclusions

Back 10

Positive conclusion with negative premises, or Illicit Negative/Affirmative

Hint 10

All dogs are animals.
Some pets are dogs.
Therefore, some pets are not animals.

Front 11

(FORMAL)
Using more than 3 terms in a syllogistic argument.

Back 11

Quaternio terminorum, or the four-term fallacy

Hint 11

No Republicans are Democrats. All conservatives are Republicans. Therefore, no conservatives are democrats.

Front 12

(FORMAL)
"All x are y, all z are y. Therefore all x are z."

Back 12

Undistributed middle

Hint 12

All horses have 4 legs. All dogs have 4 legs. Therefore all dogs are horses.

Front 13

(INFORMAL, LINGUISTIC)
When the meaning of a sentence is confused by altering stressed and unstressed syllables.

Back 13

Accent

Hint 13

Light your cigarette. (v.s.) Light YOUR cigarette.

Front 14

(INFORMAL, LINGUISTIC)
Ambiguous meaning created by the confusing arrangement of a pronoun.

Back 14

Amphiboly

Hint 14

"The dutchess has a fine ship, but she has barnacles on her bottom"

Front 15

(INFORMAL, LINGUISTIC)
Confusing the role of a description to suggest that it applies in the same manner to the parts as well as the whole.

Back 15

Composition

Hint 15

"I will gather my strongest men into one regiment. This will be my strongest regiment."

Front 16

(INFORMAL, LINGUISTIC)
Confusing the role of a description to suggest that if it applies to the whole group, then it also applies to the individual parts.

Back 16

Division

Hint 16

The Icelanders are the oldest nation on earth. This means that Bjork must be older than other pop stars.

Front 17

(INFORMAL, LINGUISTIC)
Using words ambiguously on purpose, often with humorous intent.

Back 17

Equivocation

Hint 17

"Elephants are not found in britain, so if you have one don't loose it or it will never be found again"

Front 18

(INFORMAL, LINGUISTIC)
Treating usually descriptive words as if they were objects.

Back 18

Reification (ree-uh-fahy)

Hint 18

"Extracting the blueness of the flower for our new herbal tea."

Front 19

(INFORMAL, OMISSION)
Asserting a set of binding consequences to a set of outcomes where, in fact, nothing is bound.

Back 19

Bogus Dilemma

Hint 19

If you tell the truth men will hate you, and if you tell lies gods will hate you. Since you must either tell the truth or tell lies, must be hated either by men or by the

Front 20

(INFORMAL, OMISSION)
Failure to specify the amount or percentage of a group an assertion targets.

Back 20

Concealed Quantification

Hint 20

"Garage mechanics are crooks," - all mechanics?

Front 21

(INFORMAL, OMISSION)
Applying the process of elimination to a situation where there is not a fixed number of alternative options.

Back 21

Damning the alternatives

Hint 21

Einstein's theory has to be the right answer. All the others have been proven hopelessly wrong.

Front 22

(INFORMAL, OMISSION)
Saving face by redefining your original assertion.

Back 22

Definitional Retreat

Hint 22

"When I said that we were ruled by tyrants, I was naturally referring the tax-collectors and administrators, rather than to Your Majesty"

Front 23

(OMISSION)
Mistaking the goal of "proving" a point to mean "testing" a point

Back 23

The Exception that Proves the Rule

Hint 23

none

Front 24

(OMISSION)
To first use a word in its commonly accepted meaning, but then retreat into its strictly literal definition later

Back 24

Extensional Pruning

Hint 24

"All I said is that I'd sell you a computer. I didn't say it would work."

Front 25

(OMISSION)
To use exact words to describe inexact concepts

Back 25

False Precision

Hint 25

"54% generous"

Front 26

(OMISSION)
Using colorful language to disguise a number

Back 26

Half-concealed Quantification

Hint 26

"Practically every single case of..."

Front 27

(OMISSION)
Using ambiguous meanings with the intent to hide behind them later

Back 27

Hedging

Hint 27

Bush's definition of torture

Front 28

(OMISSION)
Using one's lack of knowledge about a subject for deduction

Back 28

Argument from ignorance

Hint 28

"I never heard about the party so it must not have been very popular"

Front 29

(OMISSION)
Ignoring the argument, usually with theatrics

Back 29

Argumentum ad Lapidem (Appeal to the stone)

Hint 29

Philosopher kicks a stone while discussing the existence of objects

Front 30

(OMISSION)
Repeating an argument to erode support for the opposition

Back 30

Argumentum ad Nauseam

Hint 30

none

Front 31

(OMISSION)
Considering only one side (pro or con)

Back 31

One-sided asessment

Hint 31

none

Front 32

(OMISSION)
To argue against an example, perhaps successfully, but fail to make ground in your own argument

Back 32

Refuting the Example

Hint 32

none

Front 33

(OMISSION)
To avoid losing an argument by moving to a broader argument that permits your case

Back 33

Shifting Ground

Hint 33

none

Front 34

(OMISSION)
To place inordinate pressure onto whomever is only trying to defend the status quo. "Prove it is" requires fewer assumptions than "prove it isn't"

Back 34

Shifting the Burden of Proof

Hint 34

none

Front 35

(OMISSION)
Requesting special treatment without evidence to support such treatment

Back 35

Special Pleading

Hint 35

none

Front 36

(OMISSION)
To misrepresent your opponent's position and argue against a different case altogether

Back 36

Straw Man

Hint 36

none

Front 37

(OMISSION)
Opposition based on minor, incidental aspects of an argument

Back 37

Trivial Objections

Hint 37

none

Front 38

(OMISSION)
When both the pro and con sides accept an assumption without evaluating it

Back 38

Unaccepted enthymemes

Hint 38

Al gore is a pompous prick because he said he invented the internet

Front 39

(OMISSION)
To argue against an idea because it is not perfect

Back 39

Unobtainable Perfection

Hint 39

Nuclear power

Front 40

(INCLUSION)
The abuse of technical jargon to disguise an argument

Back 40

Blinding with Science

Hint 40

none

Front 41

(INCLUSION)
To invoke envy, fear, hatred, pride, superstition, or sentiment in general

Back 41

Emotional Appeals

Front 42

(INCLUSION)
To admit unproven evidence by accusing the opponent of a specific example of ignorance

Back 42

Every Schoolboy Knows

Hint 42

none

Front 43

(INCLUSION)
To dismiss an argument because of its source

Back 43

Genetic Fallacy

Hint 43

Not quite poisoning the well...

Front 44

(INCLUSION)
Attacking the opponent instead of the argument

Back 44

Argumentum ad Hominem (abusive)

Hint 44

none

Front 45

(INCLUSION)
Appealing to the opponent's personal principles (thereby admitting evidence that is outside the argument)

Back 45

Argumentum ad Hominem (circumstantial)

Hint 45

none

Front 46

(INCLUSION)
To work towards proof of an argument that is altogether different from the current argument

Back 46

Ignoratio elenchi (Irrelevant Thesis)

Hint 46

I will oppose shorter school days by proving the value of education.

Front 47

(INCLUSION)
Using a joke to distract the audience

Back 47

Irrelevant Humor

Hint 47

none

Front 48

(INCLUSION)
Because a person is poor or rich, they are right or wrong

Back 48

Argumentum ad Lazarum (poor), Argumentum ad Crumenam (rich)

Hint 48

If you're so smart, why aren't you rich?

Front 49

(INCLUSION)
Using prejudiced words intentionally

Back 49

Loaded Words

Hint 49

"Hitler summons war lords, Truman consults defense chiefs"

Front 50

(INCLUSION)
Ad hominem attacks on a person or group responsible for an idea

Back 50

Poisoning the Well

Hint 50

none

Front 51

(INCLUSION)
Because an idea is popular, it must be right

Back 51

Argumentum ad Populum

Hint 51

none

Front 52

(INCLUSION)
To intentionally lead an audience away from the initial argument with another argument

Back 52

Red Herring

Hint 52

none

Front 53

(INCLUSION)
Using an argument that supports one course of action to support MORE of it

Back 53

The Runaway Train

Hint 53

"Setting the speed limit to 50mph will save lives, 40mph will save more, therefore the speed limit should be set to 0mph"

Front 54

(INCLUSION)
To suppose that a single step in a particular direction will result in the entire distance being traversed

Back 54

The Slippery Slope

Hint 54

none

Front 55

(INCLUSION)
Trying to undermine a claim by admitting the opponent's own behavior as evidence in oposition

Back 55

Tu Quoque (two quoe quay) ("You also")

Hint 55

Al Gore's jet planes

Front 56

(INCLUSION)
To use support for your argument from a powerful figure as evidence

Back 56

Argumentum ad Verecundiam (appeal to authority)

Hint 56

none

Front 57

(INCLUSION)
Accepting an idea because you would prefer it to be true

Back 57

Wishful thinking

Hint 57

none