1. Sweeping Generalization
The informal fallacy of sweeping generalization consists of using some statement in an all-inclusive way without allowing for any exceptions.
For example, if someone writes that the distinction between human beings and animals is our high IQ, that is far too sweeping. It would leave out severely retarded people; new born babies, and so forth.
Sweeping generalizations occur even in science. Chemists state that water boils at 212˚F, but if we were mountain climbing we would not find that to be accurate.

2. Accident
David L. Fairchild: The fallacy of accident is committed when a general rule is applied to a specific case it was not intended to cover. Typically, the general rule it cited (either directly or implicitly) in the premises and then wrongly applied to the specific case mentioned in the conclusion.
Example: University policy at IPFW prohibits an instructor from giving any exams, finals or otherwise, during the week preceding the designated final exams week. If a student requests an early final exam in order to complete course requirements in time to start a new job in another city, I may deny her request on the grounds that university policy forbids such an exam.

3. Accident II
Comment: My refusal in such a case demonstrates an unwillingness to consider the spirit of the policy, which is designed to prevent instructors from taking unfair advantage of their students by requiring them to take final exams in some classes while they are still completing class work in others. The student’s request would seem to constitute a legitimate exception to the general policy. My refusal here is a fallacy of accident.

4. Accident III
Another example: Property should be returned to its rightful owner. That drunken sailor who is starting a fight with his opponents at the pool table lent you his .45-caliber pistol, and now he wants it back. Therefore, you should return it to him now.
The general rule is that property should be returned to its rightful owner, and the specific case is the sailor who wants his gun returned. The rule does not apply because the return of the property might result in serious injury or death. The fallacy of accident gets its name from the fact that one or more accidental features of the specific case make it an exception to the rule. The accidental features in this example are that the sailor is drunk, that he is starting a fight, and that the property in question is dangerous.

5. Accident
General Rule
Misapplied
Specific case

6. Hasty Generalizations (Converse Accident)
Hasty generalization is the mirror image of sweeping generalization. The fallacy of hasty generalization is committed when one argues that because a statement is true for some particular, often exceptional, cases it is true generally for all cases. Typically this fallacy results from a sample which is either too small or too biased an unrepresentative to justify the warrant for the inference.
If you think all the marbles in an urn are black on the grounds that a sample of one was black, you commit this fallacy.
Another example: Ten Arab fundamentalists hijacked planes and crashed them into the World Trade Center in New York City. The message is clear: Arabs are nothing but a pack of religious fanatics prone to violence. This is a hasty generalization.

7. Hasty Generalizations (Converse Accident) II
Specific case(s) (not representative)
Generalization
General Rule

8. Hasty Generalizations (Converse Accident) III
On six different occasions I drank a bottle of Cheapskate beer and found it flat and bitter. Probably I would find every bottle of Cheapskate beer bitter.
This argument does not commit the fallacy of hasty generalization because it is unlikely that the sample is atypical of the group. The fact that the taste of beer typically remains constant from bottle to bottle causes the argument to be strong, even though only six bottles of beer were sampled.

9. Hasty Generalizations (Converse Accident) IV
In the case of large samples, if the sample is not random, it may not be typical of the larger group.
Example: One hundred thousand voters from Orange County, California, were surveyed on their choice for governor, and 68 percent said they intend to vote for the Republican candidate. Clearly the Republican candidate will be elected.
Even though the sample cited in this argument is large, the argument commits a hasty generalization. The problem is that Orange County is overwhelmingly Republican, so the mere fact that 68 percent intend to vote for the Republican candidate is no indication of how others in the state intend to vote. In other words, the survey was not conducted randomly, and for this reason the argument is fatally flawed.

10. I don’t know enough to have an opinion…
A…fascinating recent survey showed the direction in which polling should head. The NPR-Kaiser-Kennedy School poll conducted an intriguing experiment. The poll asked voters to state their views on two current education issues. Robert Siegel explained the procedure.
SIEGEL: Now an interesting finding about polls…It’s about the answer that we too hastily discard, the answer, “I don’t know.” The folks who designed the education poll did something special with two of the questions, one about school vouchers and one about charter schools. Half the people surveyed were asked… “Are you in favor or opposed to vouchers on charter schools?” And half were given the third option, “I haven’t heard enough about that to have an opinion.”

11. I don’t know enough to have an opinion II
The results of the experiment were remarkable. Among respondents asked simply if they favored or opposed charter schools, here was the breakdown:
Favor charter schools : 62%
Oppose charter schools: 29%
Don’t know: 9%
The 9% had voluntarily said they didn’t know. But for the second group of respondents, “I don’t know” was given an explicit third choice. Here was the new breakdown in opinion:
Favor charter schools : 25%
Oppose charter schools: 12%
Don’t know: 63%

12. I don’t know enough to have an opinion III
Obviously, when the poll is conducted in the first way, it produces a completely misleading impression. But that is the way opinion polls are routinely conducted and reported. Poll stories routinely give the impression that an informed electorate has weighed in on a policy question. It’s a pleasing image, straight from our civic texts – but one that is frequently wrong.
The Daily Howler <

13. Begging the question
The fallacy of begging the question is a circular argument in which we already assume the point that we are trying to prove. One “begs” the other person to grant some conclusion at the very beginning of the argument.
The classic example: Some people say they can prove God exists. When asked how, they reply, “Well, the Scriptures say very clearly that God must exist.” Then, when asked why we should believe the Scriptures, they answer, “The Scriptures are divinely inspired by God himself, so they must be true.” The problem with such reasoning is that the claim at issue – whether it’s the case that God exists-turns out to be one of the very premises the argument is based on. If we can’t trust the Scriptures, then the argument isn’t any good, but the reason for trusting the Scriptures requires the existence of God, the very argument that we were arguing for in the first place.

14. Begging the questions
Premises: Key Premise Ignored
Premises
Conclusion
Conclusion

15. Begging the question II
The fallacy of begging the question is committed whenever the arguer creates the illusion that inadequate premises provide adequate support for the conclusion by leaving out a key premise, by restating the conclusion as a premise, or by reasoning in a circle.
Another example of begging the question: The ministers of Salem allegedly decided whether a woman should be killed as a witch by using the following method: The accused woman would be ducked in water, and if she drowned that proved she wasn’t a witch. However, if she survived that showed she was a witch and should be killed.

16. Complex question
A sister fallacy goes by the name of complex question, and it occurs when a single question that is actually two (or more) questions is asked and a single answer is then applied to both questions.
Complex questions are so structured that in order to answer one explicit and seemingly straightforward question, you must also give an affirmative answer to another, usually implicit and less straightforward question. The classic example is “Have you stopped beating your wife yet?” No matter how this question is answered, the claim drawn is that you are or were a wife beater.

17. Complex Questions II Here is a blatant example:
Joe: Have you stopped cheating on exams?
Pete: No!
Joe: Oh, so you admit that you still cheat on exams?
Pete: No, I meant to say yes!
Joe: Oh, so you admit that you used to cheat on exams?
Joe’s apparent single question is really two questions rolled into one.
Question 1: Did you cheat on your exam in the past?
Question 2: If you did cheat on exams in the past, have you stopped now?
By applying Pete’s single yes or no answers to both questions, Joe commits the fallacy of the complex, or loaded question.

18. Complex Questions III Here is a more realistic example:
Hon. Flora MacDonald (Kingston and the Islands) [speaking in the Canadian House of Commons]: Madam Speaker, my question is also directed to the Minister of Finance. I would like to say to him that his policies are directly responsible for the fact that 1,185 more Canadians are without jobs every singe day, 1,185 more Canadians with families to feed and mortgages to pay. How long is the minister prepared to condemn 1,200 more Canadians every day to job loss and insecurity because he is too stubborn and too uncaring to change his policies?

19. Complex Questions IV
This question is complex because it unfairly rolls three questions into one.
Question 1: Are the Minister of Finance’s policies directly responsible for the fact that 1,185 Canadians lose their jobs every single day?
Question 2: If so, are these policies allowed to continue because the Minister is too stubborn and uncaring to change his policies?
Question 3: If the Minister is too stubborn and uncaring to change his policies, how much longer will this stubborn and uncaring attitude continue?
To respond to a complex question effectively, you must often distinguish the different questions being asked and respond to each individually.

20. The argument from ignorance
The fallacy of appeal to ignorance occurs when an arguer asserts that a claim must be true because no one has proven it false, or , conversely, that a claim must be false because no one has proven it true.
Example: Ghosts must exist. No one has proven that they don’t exist.
Ghosts must not exists. No one has proven that they do exist.
Each of these examples suffer from the same basic flaw: it assumes that the lack of evidence for (or against) a claim is good reason to believe that the claim is false (or true). If such reasoning were allowed, we could “prove” almost any conclusion.

21. The argument from ignorance II
Is it ever legitimate to treat a lack of evidence for a claim as evidence that the claim is false? In some cases, yes. Two exceptions, in particular should be noted.
First, sometimes the fact that a search hasn’t found something is good evidence that the thing isn’t there to be found. Here are two examples:
We’ve searched this car from top to bottom looking for the stolen jewels and no trace of the jewels has been found. Therefore, probably the jewels aren’t in the car.
After years of extensive scientific testing, there is no evidence that substance XYZ is toxic to rodents. Therefore, it is reasonable to conclude that substance XYZ is not toxic to rodents.

22. The argument from ignorance III
It is important to keep in mind, however, that this “fruitless search” exception applies only when (1) a careful search has been conducted, and (2) it is likely that the search would have found something if there had been anything there to be found.
The second exception applies to cases in which special rules require that a claim be rejected as false unless a certain burden of proof is met. Here is an example:
In the American legal system, a criminal defendant is legally guilty only if her guilt is proved beyond a reasonable doubt. My client has not been proven guilty beyond a reasonable doubt. Therefore, my client is not legally guilty.

23. Argument to the masses
The argument to the masses fallacy is committed when someone attempts to win acceptance of a claim by appealing to emotional techniques designed to whip up the enthusiasm of the audience. This fallacy has two common forms, band wagon (everyone is doing it) and snob appeal ( do you care enough to send the best?).
On a psychological level the argument appeals to our desire to belong, to be part of a group with values and beliefs in common. To think differently than the majority is made to appear conceited, as if we know better than everybody else does. Rather than standing apart in nonconformity, we are urged to join the crowd, be one of the guys, and so forth.

24. Argument to the masses II
Proverbs, adages, and old saws are often used to persuade us to accept ideas that we might otherwise reject. The implication is that these truths are basic and self-evident, and we would be foolish to go against tried and true knowledge.
One of the major problems with proverbs, of course, is that they often contradict one another:
On the one hand: But on the other hand:
Look before you leap. He who hesitates is lost.
Many hands make light work. Too many cooks spoil the broth.
Better safe than sorry. Nothing ventured, nothing gained.

25. Argument to the masses II
Proverbs are often used to persuade people of their position, arguing that we cannot doubt the wisdom of the ages. However, this wisdom is inconsistent, and one supposedly timeless truth cancels another.
Snob appeal is another form of argument to the masses. It plays on our desire to belong to the “exclusive” bandwagon of the select or superior few.
Example: A Rolls-Royce is not for everyone. If you qualify as one of the select few, this distinguished classic may be seen and driven at British Motor Cars. (By appointment only, please).

26. Argument to the masses III
The basic pattern of the argument is this:
Everybody (or select group of people) believes or does X.
Therefore, you should believe or do X, too.
Bandwagon argument is an argument that plays on a person’s desire to be popular, accepted, or valued, rather than appealing to logically relevant reasons or evidence. Here is an example:
I can’t believe that you’re going to the library on a Friday night! You don’t want people to think you’re a nerd, do you?

27. Argument to the masses IV
This is the fatal flaw in the bandwagon approach and in the argument to the masses in general. We cannot establish truth by counting heads or taking a poll. If we conform to what most people think, we could be seriously misled. Various accepted policies have turned out poorly, such as slavery and the election of Adolph Hitler that carried him to power.

28. False Cause
False cause is an informal fallacy that occurs when the conclusion of an argument depends on some imagined causal connection that probably does not exist.
For example: During the past two months, every time that the cheerleaders have worn blue ribbons in their hair, the basketball team has been defeated. Therefore, to prevent defeats in the future, the cheerleaders should get rid of those blue ribbons.
This argument depends on the supposition that the blue ribbons caused the defeats. This argument illustrates a variety of the false cause of fallacy called post hoc ergo propter hoc (“after this, therefore on account of this”).

29. False Cause II
In our arguments we should be careful not to impute causation to an event just because it occurred before another. For example, we should not argue that since the city allocated more money to the police budget last year and crime only increased so the way to reduce crime is to cut the budget.
The other form of the causation mistake is to link two events as cause an effect when they have no connection to each other. For example, if we write that the number of student’s that receive “A’s” in critical thinking are responsible for a decrease in pollen counts. Of course, most absurd causal connections are not as blatant.

30. False Cause III
For example, Harvard University boasts a high average income for its graduates, but is that due to the education they receive? Most Harvard students are already intelligent, highly motivated, and come from wealthy families that can provide access to high-level jobs.
The English reformer Thomas Malthus observed that pious hard-working farmers owned cows while drunken and shiftless ones did not. He therefore urged Parliament to give cows to farmers who had none in order to make them sober and hard working.

31. Irrelevant conclusion
Irrelevant conclusion simply means that the conclusion of an argument does not follow from the premises offered for it. Sometimes it is called a non sequitur (which, in Latin, means “it does not follow”).
The fallacy of irrelevant conclusion can include a number of the fallacies already described. The argument to the person and from authority, the appeal to pity, and so forth.