Fallacies are mistaken beliefs based on unsound arguments. They derive from reasoning that is logically incorrect, thus undermining an argument's validity.
Fallacies are difficult to classify, due to their variety in application and structure. In the broadest sense possible, fallacies can be divided into two types: formal fallacies and informal fallacies.
Let's take a look at the variations that exist within these categories.
Formal (or deductive) fallacies occur when the conclusion doesn't follow the premise. These are often referred to as non-sequiturs, or conclusions that have nothing to do with initial claims. In formal fallacies, the pattern of reasoning seems logical but is always wrong. A deductive argument often follows the pattern: (1) All dogs have legs. (2) Tiny is a dog. Therefore: (3) Tiny has legs.
Appeal to Probability - This is a statement that takes something for granted because it is probable or possible.
Bad Reasons Fallacy - Also known as Argumentum ad Logicam, in this type of fallacy, the conclusion is assumed to be bad because the arguments are bad.
Masked Man Fallacy - Also known as the Intentional Fallacy it involves a substitution of parties. If the two things that are interchanged are identical, then the argument is assumed to be valid.
Non Sequitur - A fallacy wherein someone asserts a conclusion that does not follow from the propositions.
Informal (or inductive) fallacies abound. Not only are we more likely to come across them than formal fallacies, their variations are endless. While formal fallacies are identified through an examination of the statement or claim, informal fallacies are identified through supporting evidence.
In these instances, the statement or claim is not supported with adequate reasons for acceptance. A strong inductive argument follows this pattern: (1) The sun has not exploded for all its existence. Therefore: (2) The sun will not explode tomorrow.
There are so many varieties of informal fallacies they can be broken down into subcategories. Let’s examine some of those subcategories.
Presumption of truth without evidence can also cause fallacious reasoning. Examples of these fallacies include:
Complex Question Fallacy - This involve questionable assumptions.
Hasty Generalization Fallacy - This is based upon only one abnormal situation. It is the revers of a sweeping generalization fallacy.
Post Hoc, Ergo Propter Hoc - This (meaning “after this, therefore because of this”) is based upon an assumption of cause and effect, A happened, then B happened, so A must have caused B.
Cum Hoc, Ergo Propter Hoc - This fallacy (meaning “with this, therefore because of this”) is when the person making the argument connects two events which happen simultaneously and assumes that one caused the other.
Slippery Slope Fallacy - This falsely assume the consequences of actions.
Sweeping Generalization Fallacy - This includes too broad of an application of a premise.
Tu Quoque Fallacy - This applies the concept of “Look who’s talking” and is used to turn criticism against the other person.
Appeal to Ignorance - Or Arguing from Ignorance, these fallacies abound in everyday conversation, advertising, politics, and history. This fallacy argues that a proposition is true because it has not yet been proven false.
Circular Argument - Also referred to as Circulus in Probando, this fallacy is when an argument takes its proof from a factor within the argument itself, rather than from an external one.
False Dilemma- Sometimes referred to as Bifurcation, this type of fallacy occurs when someone presents their argument in such a way that there are only two possible options.
A fallacy can also be caused by a lack of clarity or by a misunderstanding of the words. Examples of these fallacies include:
Accent Fallacies - These are based on the stress or emphasis of word or word parts is unclear
Equivocation Fallacies - These occur when words are used multiple times with different meanings.
Straw Man Fallacies - These include misrepresentations to make an argument look weak.
These fallacies attempt to persuade people with irrelevant information, appealing to emotions rather than logic. Examples of these fallacies include:
Appeal to Authority - also referred to as Argumentum ad Verecundia (argument from modesty). In this case, rather than focusing on the merits of an argument, the arguer will try to attach their argument to a person of authority in order to give credence to their argument.
Appeal to Popular Opinion - This type of appeal is when someone claims that an idea or belief is true simply because it is what most people believe.
Attacking the Person - Also known as ad Hominem, this is quite a common occurrence in debates and refers to a person who substitutes a rebuttal with a personal insult.
Bandwagon Fallacy - This contains arguments that are only appealing because of current trends and growing popularity.
Gambler’s Fallacy - This assumes that short-term deviations will correct themselves.
Genetic Fallacy - This involves acceptance or rejection of concepts based on their source, not their merit.
Red Herring Fallacy - This uses irrelevant information or other techniques to distract from the argument at hand.
Weak Analogy - These fallacies employ analogies between things that are not really alike.
In argumentation or debate, bad reason fallacies are quite common. How often do you hear people compare two unrelated things while making judgments? We sometimes make character judgments about others based upon their material possessions or the friends they keep when one tends to have nothing to do with the other.
When making a case in a research paper or essay, it's easy to fall into the trappings of an appeal to authority fallacy. Examples, statistics, and testimony are all important measures of supporting evidence in an academic paper. We just need to make sure that we're drawing proper conclusions from the authority figure to the case we're developing.
In advertising, appeal to authority fallacies abound. Celebrity endorsements are popular for a reason. If we decide we like the lifestyle of a certain celebrity, then we are likely to purchase the sports drink, jewelry, or organic food they are pitching. This is an easy fallacy to fall prey to. Perhaps if we purchase this item being advertised, we might be more like our beloved celebrity. It might be best, however, to purchase a product based upon its proven benefits, not the celebrity being paid to pitch it.
If you watched any of the 2017 presidential election debates, you would've seen countless attacking the person fallacies. Political opponents spend hundreds of thousands of campaign dollars to undermine their opponent's legitimacy and make them look unqualified.
As we can see, there are many different types of fallacies. Informal fallacies are particularly complex because layers of subcategories exist within them. Now that you know what some of the most prevalent fallacies look like, we hope you'll be able to identify these lapses in logic right away! Take a look at Examples of Fallacies to dive even deeper into these multi-faceted waters.