5.4 Analogical Reasoning in Legal Arguments

Analogical reasoning is among the common forms of legal reasoning. In a very general sense, legal reasoning in a democratic society seeks to treat similar behaviors in similar fashions. When a new case is deemed to be the same as another situation that occurred in the past, the past situation can be viewed as a precedent that guides the treatment of new cases. Even when there is not a clear precedent, analogical arguments are made to cite similarities with cases from the past. Analogical reasoning is also useful to argue that there are dissimilarities with the precedent when there seems to be precedent. The distinction between precedent and analogy is described in the introductory remarks of the cited paper:

Arguments from precedent and analogy are two central forms of reasoning found in many legal systems, especially ‘Common Law’ systems such as those in England and the United States. Precedent involves an earlier decision being followed in a later case because both cases are the same. Analogy involves an earlier decision being followed in a later case because the later case is similar to the earlier one. (Lamond, Grant, “Precedent and Analogy in Legal Reasoning”, The Stanford Encyclopedia of Philosophy (Spring 2016 Edition), Edward N. Zalta (ed.), URL = <https://plato.stanford.edu/archives/spr2016/entries/legal-reas-prec/>.)

Legal scholar, Cass Sunstein, describes the characteristic form of analogical thought in law this way (Cass R. Sunstein, “On Analogical Reasoning Commentary,” 106 Harvard Law Review 741 (1992). https://chicagounbound.uchicago.edu/cgi/viewcontent.cgi?article=12380&context=journal_articles

Sunstein compares analogical thinking in law with analogical thinking in everyday life. In both contexts, at its best, analogical thinking can give rise to a judgment about what’s probable but there is always uncertainty.

The relevance of similarities and differences (criterion 5 from Section 5.2 ) is especially critical in legal reasoning.

The following cases serve as examples of analogical legal reasoning in judicial opinions and are from The Bridge (cyber.harvard.edu/bridge)  a project on legal reasoning and American legal theory, from the Berkman Klein Center for Internet and Society at Harvard University, licensed under a Creative Commons Attribution 3.0 Unported license.  The two cases used here as examples are copied unchanged from The Bridge, without links for their footnotes.

This first case demonstrates analogical reasoning that is based on similarities:

In Adams v. New Jersey Steamboat Co.,⁽¹²⁾ a steamboat passenger sued the owner after the theft of valuables from the rented cabin; neither passenger nor owner had been negligent. The passenger claimed the owner nonetheless was strictly responsible, regardless of any failure or compliance with care, in light of prior case ruling that innkeepers were strictly liable for the theft of boarders’ valuables. The owner argued against strict liability and pointed to precedents rejecting liability claims by passengers on open-berth sleeping trains. For purposes of liability for theft from a passenger, should the steamboat owner be viewed as more like the innkeeper or more like the train owner? The court reasoned that A steamer carrying passengers upon the water, and furnishing them with rooms and entertainment, is, for all practical purposes, a floating inn, and hence the duties which the proprietors owe to the passengers in their charge ought to be the same.⁽¹³⁾ The court noted that both innkeepers and steamboat operators are entrusted with high levels of confidence in the face of temptations by many to endanger guests. Given this parallel relationship to guests, innkeepers and steamboat operators should bear the same kinds of duties to guests.⁽¹⁴⁾

The analogical comparison here involves the similarity between an inn and a passenger steamboat. The operators of both types of amenities are expected to hold comparable duties to guests.

The following case history, on the other hand, exemplifies reasoning by dis-analogy (dissimilarity) – a difference is seen to be more weighty than any similarities:

In Mills v. Wyman,⁽³⁹⁾ the court addressed whether a father was obliged to repay a good Samaritan for expenses incurred in caring for the father’s son when the son was near death. The father promised to make this payment but made the promise after the services were rendered. Some precedents indicated that no promise is legally enforceable if made after the fact of the proffered services; others, in contrast, suggested that moral consideration could count as a basis for enforcing such a promise. On further review, the court in Mills⁽⁴⁰⁾ found that all the cases treating moral consideration as adequate to enforce a promise involved prior “valid” consideration that had been extinguished by law, such as a legally enforceable promise to pay a debt that had been extinguished by discharge in bankruptcy. No enforceable promise remained and yet the moral obligation could supply the missing element. But the father in Mills⁽⁴¹⁾ had no such prior but now extinguished consideration; on this basis, the precedents favoring enforcement could be distinguished as disanalogous. They included a crucial trait missing in this case.⁽⁴²⁾

Here, there was not adequate similarity to past cases involving moral obligations to pay debts. There was dis-analogy – a relevant missing feature. Past cases involving moral obligation had involved a prior but legally discharged promise to pay but there was no such prior consideration in this case.