Law Quarterly

Rules, Logic, and the Legal System

By Gordon Yang


Law can be seen as a tool used to organize society. The law is made of two distinct parts: norms that guide behavior to how we believe it should be and rules that enforce the integrity of law. The strict application of rules is known as deduction. This is widely found in civil law systems, where law is not as likely to be contested over. Generalizations are made, and these generalizations fit into a generic form as a type of syllogism or formal construction. Take, for example, a rule that “Contractors with permission to personal information are required to disclose it to the government.” Contractor A does not have permission and so by a simple conditional formulation, Contractor A is not subject to disclose anything. Notice that the concept of permission is left intentionally vague here, something we will expand on later. The statement is true merely by logical construction, and truth is only preserved by negation because the choices are binary. As a result, the solution to this generic case is the only one in an ideal legal system, and therefore objective.

The question of what qualifies as permission remains, and will in turn be defined pursuant to conditions within the real-world. Suppose that the nature of the permission depends on the relationship of the grantor and the trustee, e.g. the consumer and the vendor. Then there is a distinction to be made between information carried by third parties and information directed to third parties for their use.(1)[1] Distinctions like these contribute to our conception of what constitutes as giving permission. A formal model for justice is deontic logic which expresses all normative statements in terms of obligation as required (whether by law or norms), permission, and prohibition.(2)[2] Perhaps only the most general norms need be identified, and the others just an extension of a reason-based calculus that some might call moral intuition. The general norm laid out in the Fourth Amendment is a perfect example of this: if data is given with the expectation that it be kept private (security is another matter), then it should be kept private.

Variability in cases is distinguished by their relevant factors. Consider the line of cases associated with the Third-Party Doctrine. The doctrine is invoked by the factual involvement of wrongdoing. Within the doctrine, cases are distinguished by whether they involve turning over information: (through transactions) + (voluntarily) + (regularly reviewed, recorded or processed by the company) + (by one of {x: x is medium which is some sort of proxy for the nature of the relationship that has to be related by way of analogy e.g. telegram, letters, phone calls, text messages, emails}).(3)[3] In common law, there is a doctrine that respects the decision of the more specific rule, that more suits the particular case rather than a general rule (lex specialis). This helps in the application of rules. to close in the area of relevance. Its more general counterpart is known as the principle of priority of specificity- more specific information defeats more general information.(4)[4] Specificity in scope can be zoomed in on (excluding factual situations) or expanded out.

In the common law system, precedents serve as authority for justification, and as such judges may also consider the potential implications of their decisions. The regularly reviewed factor mentioned earlier may generate a corresponding (and appropriately just) result that only information expected to be regularly handled, such as customers’ addresses and other metadata may be disclosed.(5)[5]

To make things more complicated, nuances in language may make interpretation difficult, and lend itself to multiple interpretations. Consider a rule stating a person that’s in effect granting permission to a third-party, entrusts them with his/her data. Now suppose there is a similar, but broader rule that all permissions granted are agreements that both parties consent to. A range of cases may fall under one of the rules, but also both, or none. For instance, a granting could have been given at one point but withdrawn later (in fact this is covered in the EU’s newly passed GDPR statute). Then it seems that the first rule is more relevant in deciding for the withdrawal being not allowed, because the language of the rule suggests that the permission isn’t one that requires active checking.

As you can see, considering the numerous ways in which a fairly straightforward example can be defeated by differing applications of rules, it is impossible for an exhaustive list of exceptions to be developed prior to implementation. This is where defeasibility comes into play, and thus requires interpretation. One of the main problems that arises in the application of general norms to individual cases is the classification of an individual case as belonging to one of the generic case.(6)[6] Thus, conflicts in interpretation may come from two sources: disagreement over 1) value judgments or 2) different conceptions of fitting.(7)[7] Engaging in the practice of determining facts is a large part of hearing cases. 1) may be that individuals have an overriding interest in privacy (a norm) and 2) may be the fact that an event is not wholly ‘private’ does not mean that an individual has no interest in limiting disclosure or dissemination of the information.(8)[8] The facts decide if the norm(s) in question is applicable.

The normative is the prescription of rules, that state how things should be. This can be distinguished from how things usually are, that is normality. Normality can be used as a simplifying expression. Instead of asking what a reasonable person would do, we ask how they would describe something, a concept in relation to other words. What defines contractors and personal information lays in the context of meaning of texts, or the corpus of case law. “Overwhelmingly, ‘personal’ is used to describe an individual, not an artificial being” -United States Supreme Court brief of /FCC v. AT&T (2011)/. Corpus linguistics can be used to inform and justify a decision by revealing conventional meanings, since those influence expectations. Nevertheless, such a tool can only be used to provide the background for employing logic, which validates truths.

In this article we have attempted to formalize and rationalize the way a legal system operates by examining just a small subset of the vast universe of the legal domain. The purpose was to (hopefully) illustrate some of the problems that come with doing that, and in particular, the limits of formal logic in the context of law. An exploration of possible solutions to address these problems will have to wait until next time.

Works Cited:

Beltran, Jordi & Ratti, Giovanni. The Logic of Legal Requirements. Oxford University Press, 2012.

Cases are referenced through examples and hypotheticals in

Scolnik, Alexander. Protections for Electronic Communications: The Stored Communications Act and the Fourth Amendment. Fordham Law Review Vol 78, 2009.

  1. Scolnik, Alexander. “Protections for Electronic Communications: The Stored Communications Act and the FourthAmendment.” Fordham Law Review Vol 78 (2009): 393.
  2. Atienza, Manuel & Manero, Juan. “Rules, Principle, and Defeasibility.” The Logic of Legal Requirements (2012): 241.
  3. Ibid., 390.
  4. Beltran, Jordi & Ratti, Giovanni. “Defeasibility and Legality: A Survey.” The Logic of Legal Requirements (2012): 18.
  5. Scolnik, Protections for Electronic Communications, 394.
  6. Alchourron, Carlos. “On Law and Logic.” The Logic of Legal Requirements (2012): 49.
  7. Ibid., 51.
  8. Scolnik, Protections for Electronic Communications, 361.

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