The interpretation-construction of patent claims: is linguistic indeterminacy the real enemy?

When this Kat was just a lively and curious child, one of his greatest passions was browsing through the dusty and heavy books hidden on the shelves of an old wooden bookcase at his grandmother's house. He soon discovered that some of those hefty volumes had been written, many years earlier, by his great-grandfather, a lawyer and professor of jurisprudence. Although most of the works presented a rather obsolete perspective centred upon a Christian view of the doctrine of natural law, the interesting pages full of thoughts on the origin and characteristics of legal rules are probably the roots of this Kat's fascination with legal theory. For once, therefore, allow him to begin this post not with news of a break-through judgment, but with the words of H.L.A. Hart, in his famous book 'The Concept of Law':

Whichever device, precedent or legislation, is chosen for the communication of standards of behaviour, these, however smoothly they work over the great mass of ordinary cases, will, at some point where their application is in question, prove indeterminate; they will have what has been termed an open texture. So far we have presented this, in the case of legislation, as a general feature of human language; uncertainty at the borderline is the price to be paid for the use of general classifying terms in any form of communication concerning matters of fact. Natural languages like English are when so used irreducibly open textured. 

The open texture of natural languages is an unavoidable characteristic of any human statement, whether included in a written constitution, a statute, a judgment, a contract or any other document [Merpel's warning: the long introduction is about to end, soon the word 'patent' is going to appear]. From the perspective of law, vagueness, indeterminacy and ambiguity are, at the same time, a potential weakness and a quality of legal rules, as they introduce a degree of uncertainty in the evaluation of the legality of human behaviour, but allow a margin of flexibility, which judges use to accommodate abstract rules to the various and unpredictable events of life. To borrow one of Hart's examples, an ordinance prohibiting 'vehicles in the park', in the 1960s, certainly applied to cars, motorbikes and buses. But, nowadays, we could debate whether the same ordinance applies, for example, to electric cars. Interpretation is the key to the answer and, ultimately, the process through which rules are effectively applied.

If we could make a list of the areas of law where the vagueness, indeterminacy and ambiguity of linguistic expressions is perceived as a particularly serious concern, patent law could easily make it to the top spots. In particular, the formulation and interpretation of patent claims has been the subject of a number of critical studies, which suggested, to various extents, that the main cause of concern arouse from linguistic indeterminacy. Professors Lawrence B. Solum and Tun-Jen Chiang embarked on a mission to provide a new, original approach to the matter, which is presented in 'The Interpretation-Construction Distinction in Patent Law', a 73-page long article for the Yale Law Journal. According to the abstract,

The ambiguity of claim language is generally considered to be the most important problem in patent law today. Linguistic ambiguity is believed to cause tremendous uncertainty about patent rights. Scholars and judges have accordingly devoted enormous attention to developing better linguistic tools to help courts understand patent claims.

In this Article, we explain why this diagnosis is fundamentally wrong. Claims are not often ambiguous, and linguistic ambiguity is not a major cause of the uncertainty in patent law today. We shall explain what really causes the uncertainty in patent rights, how the erroneous diagnosis of linguistic ambiguity has led the literature off-track, and what will get us back on track to solving the uncertainty problem.

Confronted with the authors' intriguing challenge to re-frame the whole claim interpretation discourse, the IPKat could not resist the temptation of devouring the article and summarizing the salient points to his readers. Firstly, however, it may be useful to look at what the interpretation-construction distinction is all about. According to a theory originally developed in the field of constitutional law (see Solum here, Whittington here - or watch the Federalist Society's 12th Annual Faculty Conference here), the distinction describes the process through which a legal text becomes a coercible legal rule: in the first phase, interpretation, a linguistic meaning is attributed to the text; in the second phase, construction, a normative value is assigned to it. The distinction aims to point out that the overall process of interpretation-construction implies the use of linguistic rules and policy considerations. For example, how can a judge determine the meaning of 'fair', in relation to a FRAND commitment? According to the interpretation-construction theory, he does so by looking at the commonly accepted usage of the word in the relevant language (interpretation) and applying a wealth of normative considerations (which is the aim of the FRAND commitment? Which is the optimal degree of balance between the parties' conflicting interests?) to it. The theory also allows to better understand why courts may change their interpretation of a specific provision through time: both the linguistic and normative context continuously evolve, albeit asynchronously (see, for example, Solum and Chiang's reconstruction of the debate on the interpretation-construction of the word 'Congress' in the First Amendment to the US Constitution).

Adapting this theoretical approach to patent law poses a relevant preliminary challenge. The process commonly applied to the evaluation of claims uses a similar distinction between interpretation and construction. However, the interpretation-construction theory used by Solum and Chiang only refers to the first phase of claim analysis (known, to IP lawyers, simply as 'interpretation'). The authors suggest, as a more clear and straightforward way to distinguish the different phases of claim analysis in patent law, that an interpretation-construction-application distinction should be used.

A Kat's great-grandfather

The key premise of the article is that the confusion between interpretation and construction is endemic in patent law. The authors believe that the issues surrounding patent claims do not arise due to linguistic uncertainty, but are caused by unrecognized policy disagreements among judges. Accordingly, Solum and Chiang challenge the effectiveness of the solutions proposed by previous studies, which focused upon the tools to be used for interpretation (which suggested looking to unbiased third-party sources such as dictionaries and encyclopaedias, to the patentee’s own usage in the patent specification, or to expert testimony), and reject the idea that claim text be innately defective (see Burk and Lemley here).

From the perspective of interpretation, which is considered to be a factual and objective inquiry into the linguistic meaning of a text, the article suggests that ambiguity, vagueness and indeterminacy rarely become insurmountable obstacles. Although there are exceptional situations where '...multiple linguistic meanings are intended and conveyed [and] the ambiguity is real and irreducible', apparent ambiguities can usually be resolved through reference to the (textual) context, or by applying the rules of grammar and syntax. Similarly, unfamiliar language usually acquires a meaning when the patterns of conventional usage are properly examined. If sufficient evidence exists, suggest the authors, the interpretative process is usually capable of determining the linguistic meaning of a text.

Further, the authors point at three common fallacies of the interpretative process, which may contaminate the construction of patent claims. First, Solum and Chiang clarify that the linguistic meaning does not depend on the patentee's unexpressed intent, which renders interpretation a tautology ('... courts will interpret claims according to the patentee’s intent, but the patentee’s intent will be to claim whatever the courts allow'). Second, the linguistic meaning should be evaluated from the perspective of a person skilled in the art and does not extend to that person's understanding of the patentee's invention. Third, interpretation, albeit necessarily textual, does not necessarily coincide with the literal dictionary definition.

From the perspective of construction, which is described as an irreducibly normative process, centred upon the analysis of the legal consequences and scope enshrined in the text, two fundamental problems arise. The article sets them out with clear words:

First, [the judge] must decide what weight to give to the linguistic meaning of text, if any. As a realist matter, judges do not have to follow the linguistic meaning in determining claim scope, and as we shall see they regularly do not. To the extent that judges choose to construct claim scope by some other point of reference, then the outcome (and the certainty/uncertainty of that outcome) will depend on that alternative point of reference. ... [T]he most common alternative point of reference is to construct patent scope to cover the patentee’s inventive idea.  

Secondly, to the extent that a judge chooses the linguistic meaning as his lodestar, the linguistic meaning may run out. Vague terms such as “near” or “approximately” are common in patent claims, and there will always be the question of how close is close enough in such cases. These borderline cases are in the construction zone. In such cases, a judge will have to resort to some alternative point of reference to resolve the dispute.

String indeterminacy? That is no
problem for the IPKat!

The authors, having restricted most of the issues concerning patent claims to their construction, suggest that the dichotomy between the 'dictionary-first' and 'specification-first' approaches to construction exhibited by the Federal Circuit actually conceals a policy disagreement on the prevalence of the linguistic meaning over the 'true' invention, or viceversa. The cause of claim uncertainty is rooted in '...'this age-old conflict between textualism and anti-textualism - a quintessentially policy conflict'. Through several examples, Solum and Chiang demonstrate that the US Supreme Court (in United States v Adams) and the Federal Circuit (in Phillips v AWH Corp.) apparently disregard the difference between an approach which takes into account the patent specifications and one that is based on how a person of ordinary skill in the art would understand the claim. This situation generates a potential confusion between the concept of 'invention' (the innovation disclosed in the patent specification) and the linguistic meaning of the claim text. Uncertainty in claim construction is, therefore, the product of this conflation, which hides a policy disagreement on the proper theory of claim construction.

The confusion generated by the situation just described allegedly generates three pernicious consequences, as (1) it wrongly places the blaming upon linguistic indeterminacy, rather than on policy disagreements, (2) it obscures judicial policy-making and the judges' determination on the optimal degree of patent scope, and (3) it conflates linguistic and policy context. 

Raising the judges' and lawyers' awareness of the distinction between interpretation and construction allows, according to the authors, to re-frame the approach towards patent claims in such a way that:

- Legal uncertainty is not automatically attributed to linguistic indeterminacy (and high reversal rates do not prove otherwise)

We should make one point clear: it is possible that linguistic ambiguity causes legal uncertainty. Our point is that this is not necessarily so. Legal uncertainty can arise from multiple causes; in particular, legal uncertainty in claim analysis can arise either because (1) judges are all faithful textualists but the linguistic meaning is ambiguous, or (2) some judges are not faithful textualists and therefore don’t follow the linguistic meaning.  

- The theory of linguistic indeterminacy should be refuted, as the use of scientific jargon, the issues related to the evolution of the language and the use of apparently ambiguous or vague terms do not usually preclude the attribution of a linguistic meaning to a claim text

The linguistic meaning exists so long as the communication between a patentee and the intended reader of a patent (i.e. a person of ordinary skill in the art) is achieved. Since we highly doubt that readers of patents find the text to be gibberish, the linguistic meaning exists. And, as we have discussed above, the linguistic meaning in cases such as Phillips, Merrill, Markman, and Retractable were in fact not hard to discern. What is hard to predict is whether a judge will choose to follow the linguistic meaning; but that is a completely different argument. 

- The debate should concentrate on policy disagreements, trying to identify a reasonable compromise between a textualist and anti-textualist approach, rather than attributing the uncertainty in claim construction to a non-existent linguistic ambiguity

The final take-away is that the uncertainty will persist until judges reach normative agreement about claim analysis policy (or such normative agreement is imposed from above, such as by Congress). We do not have any suggestions about how to force life-tenured judges to reach policy consensus. But understanding the nature of the problem is a predicate to finding a solution. Without adopting the interpretation-construction distinction and overcoming the linguistic indeterminacy fallacy, no progress can be made on the claim analysis problem. 

Although Solum and Chiang's work may give the impression of being a thoughtful research with little practical significance, this Kat thinks that it could indeed stimulate a deeper reflection on how claims are conceived, drafted and litigated. It is evident that a certain degree of flexibility, in patent law as in any other areas of law, cannot be eliminated, and could actually be deemed as beneficial. The interpretation-construction distinction shows, on one side, that the linguistic complexities of claim drafting may not yield the result the patentee hoped for, as construction rests firmly in the hand of judges. On another note, it suggests that the quality of the patent system would improve if normative considerations were more openly discussed and better identified before the courts' review, as the outcome of the assessment of patent claims, whether conducted by patent examiners [Merpel's note: from the interpretation-construction perspective, what would Solum and Chiang say about this or this? Conflation examples?] or judges, would probably be better aligned and more predictable. Finally, the distinction puts greater emphasis on the necessity of reaching a balance between a textualist and an anti-textualist approach to patent claims. Where does that balance lie? This Kat suspects that the re-framing of the claim analysis discourse could not be deemed complete until a reasonable answer is found. Perhaps, a starting point would be to re-evaluate the importance of filtering the interpretation and construction processes through the perspective of a person of ordinary skill in the art, who is supposedly equipped with a smart brain, but is no expert when it comes to policy choices.