In this period of “alternate facts,” a 24-hour news cycle, and an internet that can provide whatever answer a person seeks, it can be difficult to convince parents and patients using facts alone. Parents may respond using their own “facts” leaving you frustrated and unprepared to dive further into the conversation.

Without further conversation and as more parents become convinced by the counter-arguments, these “alternative facts” become widely held “truths.” Often the counter-arguments are based on fallacies, or errors of logic or reasoning. Different types of logical fallacies have been described in an article by David Ferrer, published on The Best Schools website. The article, which includes some short video examples, describes 15 types of fallacies:

• Ad hominem attacks — Criticizing the messenger in the absence of a counter-argument related to the fact being discussed.
• Straw man attacks — Attacking a position or fact that was not actually put forth. For example, oversimplification of a complex subject or statement to make it appear false.
• Appeal to ignorance — Taking advantage of what is not known. Using the notion that something has never been proven definitively is a common example of this type of fallacy.
• False dichotomy — Making a position appear to have only one of two possible options when the options are not mutually exclusive or when more than two options exist.
• Slippery slope — Arguing against a fact by suggesting unlikely, extreme outcomes.
• Circular argument — Using the preliminary assumption as the basis for arriving at the same conclusion.
• Hasty generalization — Jumping to conclusions without reviewing all available evidence.
• Red herring — Using a parallel or seemingly relevant argument to distract from the original point being discussed.
• Appeal to hypocrisy — Suggesting deception or insincerity of the messenger as a way to neutralize or distract from the issue.
• Causal fallacy — Incorrectly identifying two things as causally associated either without enough evidence to do so (false cause); solely based on one occurring before the other (post hoc); or because they were found together (correlational fallacy).
• Fallacy of sunk costs — Continuing with, or suggesting continuation of, a project based on the resources invested to date without consideration of future resources that will be incurred if the project continues.
• Appeal to authority — Considering something to be true simply because a perceived authority said it is so (without evidence) or because it was said to be true by citing authority figures who are not qualified in that field.
• Equivocation or ambiguity — Delivering a message that is intentionally deceitful or misleading.
• Appeal to pity — Evoking emotion to deter or replace the discussion of facts.
• Bandwagon approach — Suggesting something is true because it is a popular belief; it is accepted by authorities or large numbers of people; or because someone specific, based on their reputation, agrees.

Recognizing these fallacies, and helping your patients and families recognize them may be useful to approaching vaccine-related conversations as well as helping sort out fact from fiction in general. To that end, the VEC recently created a new Special Topics sheet, titled Logical Fallacies and Vaccines: What You Should Know. The new, four-page sheet includes a definition for each type of fallacy, a common example of how the fallacy is used to argue against vaccines, and a “reality check” statement about the related myth.

As with other Special Topics sheets, and most VEC materials, this information can be photocopied for distribution, linked from your website, or shared on social media.