Bifurcation
Bifurcation (black and white or false dichotomy) fallacies occur when someone presents a situation as having only two alternatives, when in fact, other alternatives exist or may exist. For example:
"There are only two versions of taekwondo history, one as described by the WTF and the other as described by the ITF."
Circulus in Demonstrando
This fallacy occurs if you assume as a premise the conclusion that you wish to reach. Often, the proposition is rephrased so that the fallacy appears to be a valid argument. For example:
"Because of the threat of AIDS, homosexuals should not be allowed in a taekwondo class. Any student who is revealed to be a homosexual should be expelled. Therefore, homosexual students will do anything they can to hide their secret, and will be open to threats of exposure. Therefore, homosexuals should not be allowed in a taekwondo class."
Note that the argument is entirely circular; the premise is the same as the conclusion. Circular arguments are surprisingly common. If you have already reached a particular conclusion once, it is easy to accidentally make it an assertion when explaining your reasoning to someone else.
Complex Question (Fallacy of Interrogation or Fallacy of Presumption)
This is the interrogative form of Begging the Question. One example is the classic loaded question:
"Have you stopped beating your wife?"
The question presupposes a definite answer to another question that has not been asked. This trick is often used by lawyers in cross-examination, when they ask questions like:
"Where did you hide the money you stole?"
Similarly, politicians often ask loaded questions such as:
"How long will this United Nations interference in our affairs be allowed to continue?"
Another form of this fallacy is to ask for an explanation of something which is untrue or not yet established.
Fallacy of Composition
Opposite of Fallacy of Division. This fallacy is to conclude that a property shared by a number of individual items, is also shared by a collection of those items, or that a property of the parts of an object, must also be a property of the whole thing. For example:
"Many of the students in the class think the taekwondo instructor is a good teacher, therefore, the class must think the instructor is a good teacher."
Converse Accident (Hasty Generalization)
This is the reverse of the Fallacy of Accident. It occurs when you form a general rule by examining only a few specific cases that are not representative of all possible cases. For example:
"The taekwondo opponent I fought at the tournament was a bad fighter. Therefore, all taekwondo practitioners are bad fighters."
Converting a Conditional
This fallacy is an argument of the form "If A then B, therefore, if B then A."
"As the rank promotion requirements are lowered, more students will be earning black belts. So, if we see the number of black belts increasing over the next few years, we will know that the promotion requirements are still being lowered."
This fallacy is similar to the Affirmation of the Consequent, but phrased as a conditional statement.
Cum Hoc Ergo Propter Hoc
This fallacy is similar to Post Hoc Ergo Prompter Hoc. The fallacy is to assert that because two events occur together, they must be causally related. It is a fallacy because it ignores other factors that may be the cause(s) of the events.
"Rank testing failures have increased since Elmo starting teaching. Elmo must not be a good teacher."
This fallacy is a special case of the more general Non Causa Pro Causa.
Denial of the Antecedent===
This fallacy is an argument of the form "A implies B, A is false, therefore, B is false." The truth table for implication displayed in the arguments topic shows why this is a fallacy.This fallacy is different from Non Causa Pro Causa that has the form "A implies B, A is false, therefore, B is false", where A does not in fact imply B at all. Here, the problem is not that the implication is invalid, instead, it is that the falseness of A does not allow us to deduce anything about B. This is the converse of the fallacy of Affirmation of the Consequent. For example:
"If a UFO appeared before me, it would prove that UFO's are real. But none ever appeared before me, so cases of alien abductions must be false."
Dicto Dimpliciter (Fallacy of Accident or Sweeping Generalization)
A sweeping generalization occurs when a general rule is applied to a particular situation, but the features of that particular situation mean the rule is inapplicable. It is the error made when you go from the general to the specific. This fallacy is often committed by people who try to decide moral and legal questions by mechanically applying general rules. For example:
"Most ITF students dislike WTF students. You are a ITF student, so you must dislike WTF students."
Fallacy of Division
This is the opposite of the Fallacy of Composition. It consists of assuming that a property of something must apply to its parts, or that a property of a collection of items is shared by each item.
"You train at dojang known for its good fighters. Therefore, you must be a good fighter." Equivocation (Fallacy of Four Terms)
Equivocation occurs when a key word is used with two or more different meanings in the same argument. One way to avoid this fallacy is to choose your terminology carefully before beginning the argument, and avoid words that have many meanings. For example:
"I have heard that your school has some "bad" black belts. I do not want my child to attend the school because I do not want him exposed to bad behavior by senior ranks."
Extended Analogy
This fallacy often occurs when some suggested general rule is being argued over. The fallacy is to assume that mentioning two different situations, in an argument about a general rule, constitutes a claim that those two situations are analogous to each other. For example, the following is an argument about sharing music over the Internet:
"I believe it is always wrong to oppose the law by breaking it."
"Such a position is odious: it implies that you would not have supported Martin Luther King."
"Are you saying that music sharing is as important as the struggle for racial equality?"
Natural Law Fallacy (Appeal to Nature)
This is a common fallacy in political arguments. One version consists of drawing an analogy between a particular conclusion, and some aspect of the natural world, and then stating that the conclusion is inevitable, because the natural world is similar. For example:
"The natural world is characterized by competition; animals struggle against each other for ownership of limited natural resources. Fighting over ownership is simply an inevitable part of human nature. It is how the natural world works."
Another form of appeal to nature is to argue that because human beings are products of the natural world, we must mimic behavior seen in the natural world, and that to do otherwise is "unnatural." For example
"To defend ourselves using a set pattern of techniques is unnatural. To be effective a self-defense, we must mimic the way animals fight in nature."
"No True Scotsman" Fallacy
Suppose I assert that no Scotsman puts sugar on his porridge. You counter this by pointing out that your friend Angus likes sugar with his porridge. I then say "Ah, yes, but no "true" Scotsman puts sugar on his porridge.
This is an example of an ad hoc change being used to shore up an assertion, combined with an attempt to shift the meaning of the words used original assertion. It is sort of a combination of fallacies.
Non Causa Pro Causa (False Cause Fallacy)
This fallacy occurs when something is identified as the cause of an event, but it has not actually been shown to be the cause. For example:
"I took an aspirin and the master rubbed my temples, and my headache disappeared. So the master cured me of the headache."
Non Sequitur
A non sequitur is an argument where the conclusion is drawn from premises that are not logically connected with it. Non sequiturs are an important ingredient in a lot of humor. For example:
"Since Egyptians did so much excavation to construct the pyramids, they were well versed in paleontology."
Plurium Interrogationum (Many Questions)
This fallacy occurs when someone demands a simple (or simplistic) answer to a complex question. For example:
"Are high kicks effective in self-defense situations? Yes or no?"
Red Herring
This fallacy is committed when someone introduces irrelevant material to the issue being discussed, so that everyone's attention is diverted away from the points made toward a different conclusion. For example:
"You may claim that the death penalty is an ineffective deterrent against crime -- but what about the victims of crime? How do you think surviving family members feel when they see the man who murdered their son kept in prison at their expense? Is it right that they should pay for their son's murderer to be fed and housed?"
Reification (Hypostatization)
Reification occurs when an abstract concept is treated as a concrete thing. For example:
"I noticed you described him as evil. Where does this evil exist within the brain? You cannot show it to me, so I claim it does not exist, and that no man can be evil."
Shifting the Burden of Proof
The burden of proof is always on the person asserting something. Shifting the burden of proof, a special case of Argumentum ad Ignorantiam, is the fallacy of putting the burden of proof on the person who denies or questions the assertion. The source of the fallacy is the assumption that something is true unless proven otherwise.
"OK, so if you do not think Ki is an energy that actually flows through the body, can you prove it?"
===Slippery Slope Argument
This argument states that should one event occur, so will other harmful events, even though here is no proof made that the harmful events are caused by the first event. For example:
"If we legalize marijuana, then more people would start to use crack and heroin, and we would have to legalize those too. Before long we would have a nation full of drug-addicts on welfare. Therefore, we cannot legalize marijuana."
Straw Man Fallacy
The straw man fallacy is when you misrepresent someone else's position so that it can be attacked more easily. Then you knock down that misrepresented position and conclude that the original position has been demolished. It is a fallacy because it fails to deal with the actual arguments that have been made.
"To believe that your martial art is the best, you must examine all the martial art styles in the world. Since you obviously have not done this, your position is indefensible."
Shifting the Burden of Proof
The burden of proof is always on the person asserting something. Shifting the burden of proof, a special case of Argumentum ad Ignorantiam, is the fallacy of putting the burden of proof on the person who denies or questions the assertion. The source of the fallacy is the assumption that something is true unless proven otherwise.
"OK, so if you do not think Ki is an energy that actually flows through the body, can you prove it?" Tu Quoque
This is the famous "you too" fallacy. It occurs if you argue that an action is acceptable because your opponent has performed it. For example:
"You are hitting too hard."
"So what? You have also been hitting too hard."
This is a personal attack, and is therefore a special case of Argumentum ad Hominem.
Fallacy of the Undistributed Middle ("A is based on B" Fallacies or "...is a type of..." Fallacies)
These fallacies occur if you attempt to argue that things are in some way similar, but you do not actually specify in what way they are similar. For example:
"Taekwondo throws are based on Judo throws? Therefore, is not taekwondo just a form of Judo?"
