Law school is a great place to discover logical fallacies. An understanding of them provides the lawyer with an easy tool for refutation. Here is an incomplete list of a few fallacies that I have seen on more than one occasion in case books and lecture.
To beg the question is to “assume its conclusion as a premise.”[1] It’s also called a circular argument.[2] The basic idea is that the conclusion is subtly hidden in one of the premises. It often occurs when the premise is simply a rewording of the conclusion. I remember at least two different professors this year that mentioned the fallacy of begging the question, but they both misused the term begging the question. They used it like news journalists, who often say, “It begs the questions…” when what they should say is “it raises the question.” For example, a journalist might say, “It begs the question of who signed off on the 25 million dollars that were over budget.”[3] An example:
Law students are well stacked because they must be able to afford paying 40k in tuition alone. Therefore, all law students are rich.
A slippery slope argument occurs when “one identifies a range of entities or conditions that are more or less continuous (or that vary by relatively small increments) and argues that something true of some of these must be true of all.” For example, if A is like B,and B is like C, is A necessarily like C?[5] In some cases it might, but it does not follow in all cases. I see this kind of argument most often played out against an action that would lead to further actions. Some professors refer to it as a “parade of horribles.”[6] A judge will justify his refusal to allow one cause of action because it might pave the way to legitimize more absurd causes of action, but such arguments potentially miss important distinctions between different kinds of actions. Thus, the easy rebuttal to such an approach is to try identify important distinctions between your case and others that are more absurd. An example:
I studied the same amount for constitutional law and civil procedure. I got a good grade in civil procedure. Therefore, I got a good grade in constitutional law. (But this argument ignores the fact that civ pro is 3 credits and con law is 4 credits)
Another common, but more subtle, fallacy is the fallacy of equivocation. It is “an argument that is valid or strong only if some word or phrase is used consistently throughout the argument, but whose statements are true only if that word or phrase is used inconsistently.”[7] So basically, this problem occurs only when a word is being used in a way that it shouldn’t be. The deception mainly arises because one word could have different meanings to it. It reminds me of Bill Clinton’s famous phrase, “It depends on what the meaning of ‘is’ is.”[8] Equivocation was a philosophical idea first recognized by Aristotle in which two different ideas corresponded to one word.[9] The law by nature is ripe for such confusion because legal terms such as negligence, willfulness, etc. are defined by the judge’s decisions that create them. It seems that a primary duty of lawyers is to argue over the definitions of these words, and likely they will often stretch the truth of interpretation out of practical necessity. An example:
I spent 5 years learning patience by playing the piano. Patience is required to be a good husband. Therefore, I will be a good husband. (Someone who can sit down and force them self to hit buttons on a keyboard has patience in that sense, but patience in being a husband is involves different kinds of actions).
There are certainly many other kinds of fallacies in law and everyday life. Some of them you intuitively know already but have not learned their corresponding technical words. The ones you should avoid the most and will see quite regularly in politics include: strawman, ad hominem, false dichotomy, fallacy of composition, and fallacy of division. If you can’t avoid them, then you risk getting silently scoffed at by logic students—or more seriously, you risk missing the truth.
[1] K. Codell Carter, A First Course in Logic 95 (Pearson Longman 2004). I highly recommend this book as an introduction into logic. I took three courses from this professor, and I would say that he is one of my top 5 teachers of all time. His writing is clear and to the point.
[7] A First Course in Logic at 99.
[9] “Things are said to be named ‘equivocally’ when, though they have a common name, the definition corresponding with the name differs from each. Thus, a real man and a figure in a picture can both lay claim to the name ‘animal’; yet these are equivocally so named, for, though they have a common name, the definition corresponding with the name differs for each.” Aristotle, Categoriae 1:1-4, (translation quoted from Richard McKeon, The Basic Works of Aristotle 7 (Random House 1941).