Thinking Thursdays: Know your Logical Fallacies (Part 2)

In my last Thinking Thursday, I discussed some common logical fallacies that lawyers may fall prey to. Specifically, I focused on non-sequitur fallacies and insufficient evidence fallacies. Based on responses to my previous blog entry, I am going to review one category in this piece, and one more in the next entry.

Today I am focusing on shallow thinking fallacies. [1]

By way of quick review, logical fallacies happen when something goes wrong with the legal syllogism. Here is a proper albeit simplistic legal syllogism:

            Major premise:           The speed limit where defendant was arrested is 45 MPH.

             Minor Premise:          The working-perfectly radar gun clocked defendant at 63 MPH.

            Conclusion:                    Defendant was speeding

In shallow thinking fallacies, the advocate begins with a faulty major premise. The claimed “rule” is not a rule at all or is poorly articulated. Below are four shallow thinking fallacies.

1. You can spot a false dichotomy fallacy when you are presented only two choices to a complex issue that in fact offer multiple choices. For example, “If you don’t like chocolate, you must like vanilla.” Or, “you are either a Star Trek or a Star Wars person.”

Here’s how the syllogism goes wrong:

The False Dichotomy
Major Premise	Minor Premise	Conclusion
People can either like Star Wars or Star Trek, but cannot like both	You like Star Trek	You do not like Star Wars
False	True	Logical but incorrect

Some legal maxims are actually examples of this fallacy, including one of the trial lawyer’s favorites: falsus in uno, falsus in omnibus (if a witness lies about one thing, he is lying about everything).

2.Next is the bandwagon fallacy, or what I like to call “teenager logic,” It goes like this, “everybody agrees with this premise.” The obvious implication—so if everyone agrees, it must be correct. The internet is full of the faceless, nameless, “everyone says so” comments, sometimes supposedly supported by unscientific or undocumented polls. Lawyers might see this argument appear in the guise of an uncited “weight of authority” type of argument: “Most other jurisdictions do it this way!” Or, “This is a well-settled rule of law, dating back to antiquity.” [no or very few citations]. This one is a fallacy mostly because the major premise (“everybody agrees”) is not supported by sufficient authority. The premise might be true, but the skeptical reader will likely see this sort of argument as a cover-up for a weak or non-existent rule. A string citation can help overcome a bandwagon fallacy—one of the few times a string citation is actually useful: To show the weight of authority.

3.The third shallow thinking fallacy, the middle ground fallacy, is also known as the King Solomon Solution. This fallacy assumes that when two parties begin from distant or opposite positions, the position squarely in the middle of those two positions is the optimal solution. This kind of fallacy relies on the predilection of humans to rely on opening anchors for negotiation points--if the opening anchor is unrealistic, the rest of the negotiation can become fallacious. You can read more about this on the website of the Harvard Program on Negotiations.

Once again, this major premise contains fundamental flaws—in this case, the flaw in thinking that both positions are equally valid. They might not be. The problem, of course, is that the solution disregards the possibility that one position is objectively reasonable (or legally sound) and the other is grossly unreasonable (or legally unsound). While our legal system encourages and values compromise, when faced with this particular fallacy compromise leads to unreasonable or legally unsound results.

The Middle Ground Fallacy
Major Premise	Minor Premise	Conclusion
The best resolution of any valuation issue is the average of the two expert opinions	Plaintiff’s expert values the property at $500,000, but Defendant’s expert values it at $150,000	The property is worth $325,000
False	True	Logical but unsupported

4. Related to this, the fallacy of false balances also starts with a fundamental flaw in the major premise. Not all sides of an issue deserve equal weight in every situation. Sometimes one side of a debate has little or no weight at all, and therefore deserves little or no role in the debate. Journalists are often accused of allowing air time to fallacious debates even though one side is without merit.

In practice, this fallacy commonly appears in debates that involve proven science. The scientific method involves repeat experiments by different groups of scientists to verify stated conclusions. Once that has happened and conclusions have been accepted by a majority of scientists in the field, it is a logical fallacy to say that a dissenting view is equally balanced to the proved science. Allowing a debate about whether the moon revolves around the earth or vice versa would fall into this category of fallacies. As with the Fallacy of False Equivalency, lawyers can fall prey to this type of fallacy because we are taught to problem-solve through negotiation and compromise.

The False Balance Fallacy
Major Premise	Minor Premise	Conclusion
The Earth might be flat or round	I believe the Earth is flat	The Earth is flat
False	True (he “believes”)	Logical but False

Keep an eye out in your writing and in your colleagues’ to help correct any of these you spot in their analysis.

Ruth Anne Robbins, Distinguished Clinical Professor of Law, Rutgers Law School

[1] Thank you to Professor Ken Chestek (Wyoming) and Professor Steve Johansen (Lewis & Clark) for these examples. They come from the upcoming second edition of our co-authored textbook, Your Client’s Story: Persuasive Legal Writing (2d ed. Wolters Kluwer, expected publication date of later this year).