Post hoc ergo propter hoc
The fallacy of post hoc ergo propter hoc (Latin for "after this, therefore because of this") is committed whenever someone asserts or implies that because an event occurred before another event, the first event caused the second. This fallacy is often called simply the post hoc fallacy, and it is the abuse of reasoning that allows politicians to take credit for everything good that happened while they were in office—and for their opponents to blame them for everything bad that happened.
Inflation tripled after Jimmy Carter was elected president. His policies must have been inflationary.
And it occurs in other contexts as welclass="underline"
Studies have conclusively proven that 83 percent of people who have died in automobile accidents last year ate ice cream within a month of their accidents. This figure strongly suggests that eating ice cream causes automobile accidents.
I took Vitamin C and my cold quickly got better. It must be true then that Vitamin C helps to fight colds.
Ad hominem
The fallacy of ad hominem (Latin for "against the man") is the assertion that someone's argument or viewpoint should be discounted because of character flaws that have nothing to do with the issues at hand. This fallacy should not be confused with simple name-calling, which is normally not an ad hominem fallacy as much as it is simply "being a jerk." Nor should the ad hominem fallacy be confused with a legitimate challenge to authority—if someone asserts a point based on his or her own authority, then it is very logical to call that authority into question.
How can people believe the theory of evolution when it is a well-known fact that Darwin was a deadbeat?
Rachel Carson's Silent Spring is the argument of a bitter woman who had an environmentalist ax to grind. There is no reason to limit DDT use on her account.
Straw man
The straw-man argument is named for a metaphor. The name invokes the image of a fight between a human opponent and a straw dummy dressed to look like a real opponent. When the straw man is knocked down, the human opponent claims victory. A straw-man argument is a summary of an opponent's position that is intentionally weak or easy to refute. By defeating an artificial, constructed version of someone else's argument, a speaker can claim victory, even though he or she has not dealt with the issues at hand.
Those who want to adopt campus-wide codes against sexist, racist and homophobic speech believe that they can prevent such kinds of speech. As noble an idea as this is, realizing the idea is practically impossible. Prejudice, a basic component of human nature, will not be eliminated with the passage of new rules and laws. Those who would try to limit free speech on campus would curtail a vital part of the American Constitution in the name of a pipe dream.
The problem with antipornography feminists is that they think sex is bad because men are evil. They tell us that any sexual relationship between a man and a woman will demean the woman and enforce the patriarchal hegemony of the man. This idea ignores the fact that a lot of men really do respect and care for women.
Dicto simpliciter
Dicto simpliciter (Latin for "I speak simply") is the illogical assumption that something that is good in general must therefore be good in a particular instance. Those who commit this fallacy are guilty of uncritically applying a general truism to a particular situation. Another word for dicto simpliciter is "oversimplification."
Milk is good for you, so everyone should drink milk.
Exercise is good, so the college should require a physical education class every semester.
It is good to date, so you should date me.
Bandwagoning
The fallacy of bandwagoning is the assertion that you should believe something or do something because everybody else does. Bandwagoning works because most people have an innate desire to agree with others—we tend to see a kind of emotional security in doing and thinking as other people do and think. This fallacy is sometimes called ad populum (Latin for "appeal to the people").
Don't be the last person on your street to buy a Clippermeister lawnmower—the only lawnmower that tells the neighbors that you care about the neighborhood as much as they do.
The "pro-life" position is becoming increasingly difficult to maintain. A recent poll suggested that 85 percent of Americans favor some form of abortion.
False dilemma
The false dilemma, or false dichotomy, is a fallacy that presents two issues as if they are the only possible choices in a given situation. The rejection of one choice in such a situation requires the adoption of the second alternative. False dichotomies should be distinguished from true dichotomies. Sometimes, only two choices exist: everything in the world is either a dog or a nondog, but everything is not either a dog or a cat. In most situations, middle grounds or other options make it irresponsible to force a choice between two alternatives.
If you are not for the war, you are against the troops. I support the war because I support our troops.
I am pro-choice because to be otherwise would be antiwoman.
PATHOS: APPEALS TO EMOTION
Aristotle called his second element of persuasion pathos, or appeals to emotion. Most people are at least as governed by their emotions as they are by reason, and they are even more likely to be motivated to adopt an opinion or course of action when logical appeals are combined with appeals that work on an emotional level. Advertisers and political campaigns have become extremely good at making these kinds of appeals—often to the point that they exclude logical arguments altogether and appeal only to emotions. They know that emotional appeals work. However, emotional appeals do not have to be manipulative; when used effectively and judiciously, they can help you connect with your reader or illustrate the emotional aspects of an issue.
Below are some of the most common kinds of emotional appeals. All of them can be used in manipulative ways, but they can also all be used in conjunction with other kinds of support to produce extremely compelling and effective arguments.
Sympathy
Most people are moved by the misfortunes of others. When we see victims of injustice, economic hardship, crime, war, or disaster, we sympathize and want to help. Appeals to sympathy or pity tend to be most persuasive when they describe the plights of individuals, and are paired with facts, statistics, and an analysis of large-scale phenomena. For example, in a piece of writing about poverty in less- developed countries, the story of a single child dying of starvation would provide a more effective emotional appeal than would a well-reasoned statistical analysis of childhood death rates in twenty-six nations, but the combination of the two would make for the best argument—it would appeal to both emotion and reason.
Fear
When people do not feel safe, or when they feel that their security (physical or economic) is in jeopardy, they become susceptible to appeals to fear. This is why automakers list safety as a major component of new cars and why politicians foreground their commitment to creating jobs and a healthy economy. An appeal to fear creates a sense of fear in the audience and connects its argument to resolving the fear. In the above example of automakers, emphasizing the safety of their cars both puts forth the possibility of being in an auto accident and offers the reassurance that if you buy one of their cars, you will be safe. Politicians who emphasize their commitment to creating new jobs and a healthy economy tap into fears of financial struggles and simultaneously offer the reassurance that if they are elected, they will put those fears to rest.