Legal Theory Lexicon 051: Vagueness and Ambiguity
Introduction This week the Legal Theory Lexicon entry focuses on "ambiguity" and "vagueness"--two important concepts for the theory of interpretation. Some legal texts are ambiguous--they can have two or more distinct meanings. And some legal texts are vague--they use concepts that have indefinite application to particular cases. And some legal texts are both vague and ambiguous--they have multiple meanings, some of which have indefinite applications. Because "vagueness" and "ambiguity" are basic concepts in the theory of interpretation, its important to master each of them and to understand the difference between them.
As always, this entry in the Legal Theory Lexicon is aimed at law students, especially first year law students, with an interest in legal theory.
Vagueness What does it mean to say that a concept, term, or phrase is vague? Let's start with some examples and then try for an elucidation of the concept. "Tall" is a good example of a vague concept. Some humans are definitely not tall--Danny DeVito, for example. Others definitely are tall--Shaquille O'Neal, for one. But the term "tall" is vague. 5'11 is almost definitely tall for a woman in the United Sates, but might be a borderline case for men. "Tall" is not the sort of quality for which there are definite criteria that sort the world into "tall" things and "not tall" things. In other words, "tall" is vague.
There are lot's of terms that are like tall: short, strong, weak, beautiful, ugly, heavy, light, warm, and cool--all of these are terms that seem to have borderline cases. And that is one way that we might define vagueness. A term is vague, we might say, if and only if it has borderline cases. A term is not vague just in case it has no borderline cases.
As you might guess, the fact of vagueness creates a variety of issues in the philosophy of language. Is vagueness built into the fabric of the universe? Or is vagueness merely a feature of the imprecision of human language? Is vagueness a property of things? Or is it a property of our knowledge of things? We won't worry about these deep questions. For the purposes of this rough and ready introduction, it is sufficient simply to see that there are such problems and that a philosophical theory of vagueness should propose to answers to them or show that they aren't true problems at all.
Ambiguity What about "ambiguity"? A concept, term, or phrase is ambiguous if it has more than one meaning. Take "cool" for example. One meaning of "cool" has to do with temperature, and in this sense, "cool" contrasts with "warm," "cold," and "hot." Another meaning of "cool" has to do with fashion and social attractiveness. And there are other senses of cool as well, as in, he kept his cool in a very pressured situation.
In a particular context, the meaning of an ambiguous term may be clear. With just a bit more context, the sentence "He's one cool dude" is likely to refer to social attractiveness and not temperature. But in some contexts, the ambiguity may be difficult to resolve: "The mojito is a cool drink" could refer either to the fact that mojitos are served chilled or to the fact that mojitos are fashionable and popular among some social groups.
And this last example, "cool" can be used to illustrate the fact that the same term can be both vague and ambiguous in the same context. If I say, "Bring me a cool drink!", my utterance may be both ambiguous--do I mean fashionable or coldish?--and vague--how far below room temperature is "cool" or are mojitos still "cool" or are they "out of style"?
Interpretation of Vague or Ambiguous Texts Now that we have a basic grasp of vagueness and ambiguity, we are in a position to see that each of these two concepts has a role to play in a theory of the interpretation of legal texts.
Many legal texts are vague. In fact, most law students become very familiar with a variety of vague terms early in their law school careers. Take "reasonable"--was the tort defendant's conduct "reasonable" under the circumstances? There will be clear cases of unreasonable conduct: driving 150 mph in a residential area. But there will also be borderline cases. Was it reasonable to drive at 55 mph in a light fog?
Some legal language general, abstract, and vague. For example, the phrase "equal protection" in the 14th amendment of the United States Constitution may refer to a very general and abstract idea of equality. Given this generality and abstraction, it may be that the "borderline" cases seem to make up the whole of equal protection doctrine. What would count as a clear example of "equal" or of "unequal"? In a common law system, general and abstract language may be translated into relatively more particular and concrete rules through case-by-case adjudication.
Vagueness is ubiquitous in the law. Ambiguity is a bit less common, because many potentially ambiguous terms or phrases are disambiguated by context. "Seizure" can refer to a physical taking or it can refer to a medical symptom, but in the Fourth Amendment of the United States Constitution, it is clear that the correct meaning is the former rather than the latter.
Conclusion "Vagueness" and "ambiguity" are important concepts in the theory of legal interpretation generally, and as a consequence, they are important to constitutional theory and the theory of statutory interpretation. I hope this Lexicon entry has clarified the distinction between these two concepts.
Links
Stanford Encyclopedia of Philosophy Article on Vagueness
(This entry was last revised on August 26, 2007.)
