Fallacies are common errors in reasoning that will undermine the logic of your argument. Fallacies can be either illegitimate arguments or irrelevant points and are often identified because they lack evidence that supports their claim. Avoid these common fallacies in your own arguments and watch for them in the arguments of others.
Slippery Slope: This is a conclusion based on the premise that if A happens, then eventually through a series of small steps, through B, C,..., X, Y, Z will happen, too, basically equating A to Z. So, if we don't want Z to occur, A must not be allowed to occur either.
Example: “If they change to parallel parking downtown, no one will want to park there and shop and so all of the stores downtown will shut down and the town’s economy will collapse.”
In this example, the author is equating parking orientation to the economic stability of the town, which is unrelated.
Hasty Generalization: This is a conclusion based on insufficient or biased evidence. In other words, you are rushing to a conclusion before you have all the relevant facts.
Example: “Even though it's only council’s first major vote, I can tell that every decision they make will be wrong.”
In this example, the author is basing their evaluation of town council’s entire four-year term on only one issue. To make a fair and reasonable evaluation the author must not look at one issue, but several issues addressed by council over a period of time.
Post hoc ergo propter hoc: This is a conclusion that assumes that if 'A' occurred after 'B' then 'B' must have caused 'A.'
Example: “The newest closure of a downtown business happened immediately after the tender for option two was awarded, so they must have closed shop because option two was going forward."
In this example, the author assumes that if one event chronologically follows another, the first event must have caused the second. But the closure of the business could have been caused by other legal processes in place long before the tender was awarded. There is no reason, without more evidence, to assume that the awarding of the tender for option two caused this business to close.
Circular Argument: This restates the argument rather than actually proving it.
Example: “Coun. Jay Brennan is a good communicator because he speaks effectively.”
In this example, the conclusion that Coun. Jay Brennan is a "good communicator" and the evidence used to prove it "he speaks effectively" are basically the same idea. Specific evidence such as using everyday language, breaking down complex problems, or illustrating his points with humorous stories would be needed to prove either half of the sentence.
Either/or: This is a conclusion that oversimplifies the argument by reducing it to only two sides or choices.
Example: “You are either for the angled parking protests or you are against democracy.”
In this example, the two choices are presented as the only options, yet the author ignores a range of choices in between such as joining committees, delegations, proper petitioning or letter writing to engage in the democratic process.
Ad hominem: This is an attack on the character of a person rather than his or her opinions or arguments.
Example: “Parallel parking supporters are not credible and therefore not entitled to have an opinion of any kind”
In this example, the author doesn't say why parallel parking supporters are not credible, much less evaluate their views on any kind of merit. Instead, the author attacks the characters of the individuals in the group.
Ad populum/Bandwagon Appeal: This is an appeal that presents what most people, or a group of people think, in order to persuade one to think the same way. Getting on the bandwagon is one such instance of an ad populum appeal.
Example: If you truly love the town, you must put a “keep angled parking” sign in your storefront.”
In this example, the author equates loving the town, a concept that people want to be associated with, particularly small businesses, with having to support a certain orientation of parking.
Red Herring: This is a diversionary tactic that avoids the key issues, often by avoiding opposing arguments rather than addressing them.
Example: “Angle parking may be unsafe in the downtown core, but what will businesses do to support their families when they go out of business from having slightly less convenient parking spots in front of their stores?”
In this example, the author switches the discussion away from the safety of the street and talks instead about an economic issue, slightly less convenient parking downtown impacting businesses. While one issue may affect the other it does not mean we should ignore safety issues because of a possible inconvenience to a few individuals.
Straw Man: This move oversimplifies an opponent's viewpoint and then attacks that hollow argument.
Example: “People who don't support the angle parking protest must be in the Mayor’s pocket.”
In this example, the author attributes the worst possible motive to an opponent's position. In reality, however, the opposition probably has more complex and sympathetic arguments to support their point. By not addressing those arguments, the author is not treating the opposition with respect or refuting their position.
Moral Equivalence: This fallacy compares minor misdeeds with major atrocities, suggesting that both are equally immoral.
Example: “Parallel parking and bike lanes downtown make Smiths Falls just like a communist state.”
In this example, the author is comparing the relatively harmless change of parking orientation to living in a state-controlled country, without free speech and other basic legal and human rights. This comparison is not only unfair and inaccurate, but also insensitive to those who have fled such states.