HYPO is a

computer program A computer program is a sequence or set of instructions in a programming language for a computer to execute. Computer programs are one component of software, which also includes documentation and other intangible components. A computer program ...

, an

expert system In artificial intelligence, an expert system is a computer system emulating the decision-making ability of a human expert. Expert systems are designed to solve complex problems by reasoning through bodies of knowledge, represented mainly as if� ...

, that models reasoning with cases and

hypotheticals A thought experiment is a hypothetical situation in which a hypothesis, theory, or principle is laid out for the purpose of thinking through its consequences. History The ancient Greek ''deiknymi'' (), or thought experiment, "was the most anci ...

in the legal domain. It is the first of its kind and the most sophisticated of the case-based legal reasoners, which was designed by Ashley for his Ph.D dissertation in 1987 at the

University of Massachusetts Amherst The University of Massachusetts Amherst (UMass Amherst, UMass) is a public research university in Amherst, Massachusetts and the sole public land-grant university in Commonwealth of Massachusetts. Founded in 1863 as an agricultural college, it ...

under the supervision of Rissland. HYPO's design represents a

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two dif ...

generalization/comparative evaluation method appropriate for a domain with a weak analytical theory and applies to tasks that rarely involve just one right answer. The domain covers US

trade secret Trade secrets are a type of intellectual property that includes formulas, practices, processes, designs, instruments, patterns, or compilations of information that have inherent economic value because they are not generally known or readily asc ...

law, and is substantially a ''

common law In law, common law (also known as judicial precedent, judge-made law, or case law) is the body of law created by judges and similar quasi-judicial tribunals by virtue of being stated in written opinions."The common law is not a brooding omnipresen ...

'' domain. Since Anglo-American common law operates under the doctrine of

precedent A precedent is a principle or rule established in a previous legal case that is either binding on or persuasive for a court or other tribunal when deciding subsequent cases with similar issues or facts. Common-law legal systems place great valu ...

, the definitive way of interpreting problems is of necessity and case-based.Rissland, E.L. and Skalak, D.B., Case-Based Reasoning in a Rule-Governed Domain, (1989) In Proceedings of the Fifth IEEE Conference on Artificial Intelligence Applications 1989,

Institute of Electrical and Electronics Engineers The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operation ...

. Thus, HYPO did not involve the analysis of a

statute A statute is a formal written enactment of a legislative authority that governs the legal entities of a city, state, or country by way of consent. Typically, statutes command or prohibit something, or declare policy. Statutes are rules made by le ...

, as required by the

Prolog Prolog is a logic programming language associated with artificial intelligence and computational linguistics. Prolog has its roots in first-order logic, a formal logic, and unlike many other programming languages, Prolog is intended primarily ...

program. Rissland and Ashley (1987) envisioned HYPO as employing the key tasks performed by lawyers when analyzing

case law Case law, also used interchangeably with common law, is law that is based on precedents, that is the judicial decisions from previous cases, rather than law based on constitutions, statutes, or regulations. Case law uses the detailed facts of a l ...

for precedence to generate arguments for the

prosecution A prosecutor is a legal representative of the prosecution in states with either the common law adversarial system or the civil law inquisitorial system. The prosecution is the legal party responsible for presenting the case in a criminal trial ...

or the

defence Defense or defence may refer to: Tactical, martial, and political acts or groups * Defense (military), forces primarily intended for warfare * Civil defense, the organizing of civilians to deal with emergencies or enemy attacks * Defense industr ...

.Delgado P. Survey of Case-Based Reasoning as Applied to the Legal Domain HYPO was a successful example of a general category of legal expert systems (LESs), it applies

artificial intelligence Artificial intelligence (AI) is intelligence—perceiving, synthesizing, and inferring information—demonstrated by machines, as opposed to intelligence displayed by animals and humans. Example tasks in which this is done include speech re ...

(A.I.) techniques to the domain of legal reasoning in

patent law A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention."A p ...

, implementing a

case-based reasoning In artificial intelligence and philosophy, case-based reasoning (CBR), broadly construed, is the process of solving new problems based on the solutions of similar past problems. In everyday life, an auto mechanic who fixes an engine by recalli ...

(CBR) system, in contrast to rule based systems like MYCIN, or mixed-paradigm systems integrating CBR with rule-based or model-based reasoning like IKBALS II. A legal case-based reasoning essentially reasons from prior

tried In law, a trial is a coming together of parties to a dispute, to present information (in the form of evidence) in a tribunal, a formal setting with the authority to adjudicate claims or disputes. One form of tribunal is a court. The tribunal, w ...

cases, comparing the contextual information in the current input case with that of cases previously tried and entered into the system.Vossos, G., Zeleznikow, J., Dillon, T., Vossos, V., An example of Integrating Legal Case Based Reasoning with Object-Oriented Rule-Based Systems: IKBALS II, (1991) In Proceedings of the Third International Conference on Artificial Intelligence and Law, 31-41, Oxford, England As noted by Ashley and Rissland (1988) CBR is used to "... capture expertise in domains where rules are ill-defined, incomplete or inconsistent". The HYPO project set out to model the creation of hypotheticals in law, where no case matches well enough. HYPO uses hypotheticals for a variety of tasks necessary for good interpretation: "to redefine old situations in terms of new dimensions, to create new standard cases when an appropriate one doesn’t exist, to explore and test the limits of a concept, to refocus a case by excluding some issues and to organize or cluster cases". Hypotheticals can include facts that support two conflicting lines of reasoning. So, it makes and responds to arguments from competing viewpoints about who should win the dispute. HYPO use

heuristic A heuristic (; ), or heuristic technique, is any approach to problem solving or self-discovery that employs a practical method that is not guaranteed to be optimal, perfect, or rational, but is nevertheless sufficient for reaching an immediate, ...

s such as making a case weaker or stronger, making a case extreme, enabling a '' near-miss'', disabling a ''near-hit'' to generate hypotheticals in the context of an argument by using the ''dimensions mechanism''.Rissland, E.L. and Ashley, K.D., A case-based system for trade secrets law, (1987) In Proceedings 1987 ACM International Conference on Artificial Intelligence and Law Dimensions have a range of values, along which the supportive strength that may shift from one side to the other. What differentiated this expert system from others was its facility not only to return a primary to best-case response but to return near-best-fit responses also.

Components

Legal knowledge in HYPO is contained in: the case-knowledge-base (CKB) and the library of dimensions. The CKB contains HYPO's base of known cases that are highly structured objects and sub-objects both real and hypothetical in the area of trade secret law. Each case is represented as a

hierarchical A hierarchy (from Greek: , from , 'president of sacred rites') is an arrangement of items (objects, names, values, categories, etc.) that are represented as being "above", "below", or "at the same level as" one another. Hierarchy is an important ...

set of frames whose slots are important facets of the case (e.g.

Plaintiff A plaintiff ( Π in legal shorthand) is the party who initiates a lawsuit (also known as an ''action'') before a court. By doing so, the plaintiff seeks a legal remedy. If this search is successful, the court will issue judgment in favor of the p ...

defendant In court proceedings, a defendant is a person or object who is the party either accused of committing a crime in criminal prosecution or against whom some type of civil relief is being sought in a civil case. Terminology varies from one jurisdic ...

secret knowledge Secrecy is the practice of hiding information from certain individuals or groups who do not have the "need to know", perhaps while sharing it with other individuals. That which is kept hidden is known as the secret. Secrecy is often controvers ...

, employer/employee data).Ashley’s HYPO system used a

database In computing, a database is an organized collection of data stored and accessed electronically. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases sp ...

of thirty cases in the area indexed by thirteen dimensions. A key mechanism in HYPO is a dimension i.e. a mechanism to allow retrieval from the CKB, in order to represent legal cases. Ashley's dimensions are composed of (i) prerequisites, which are a set of factual

predicates Predicate or predication may refer to: * Predicate (grammar), in linguistics * Predication (philosophy) * several closely related uses in mathematics and formal logic: **Predicate (mathematical logic) **Propositional function **Finitary relation, ...

that must be satisfied for the dimension to apply (ii) focal slots, which accommodate one or two of the dimension's prerequisites designated as being indicative of the case's strength along that dimension and (iii) range information, which tells how a change in focal slot value effects the strength of a party's case along a given dimension. Dimensions focus attention on important aspects of cases. In HYPO's domain of

misappropriation In law, misappropriation is the unauthorized use of another's name, likeness, identity, property, discoveries, inventions, etc without that person's permission, resulting in harm to that person. Another use of the word refers to intentional a ...

of trade secrets the dimension called “secrets voluntary disclosed” captures the idea that the more disclosures the plaintiff has made of his/her putative secret, the less convincing is his/her argument that the defendant is responsible for letting the secret. HYPO, like any other CBR system has also the following components: * Similarity/relevancy

metric Metric or metrical may refer to: * Metric system, an internationally adopted decimal system of measurement * An adjective indicating relation to measurement in general, or a noun describing a specific type of measurement Mathematics In mathema ...

s: that is, standards by which to evaluate the closeness of cases, judge their relevancy to the instant case, and select “most on point” cases. * Half-Order Theory of the Application Domain: that is, hierarchies and taxonomies of knowledge, especially regarding the application domain. * Precedent-based argumentation abilities: that is, capabilities to generate and evaluate precedent-based arguments. * Knowledge to generate hypotheticals: that is, the ability to generate hypothetical cases to deal with various circumstances, like testing the validity of an interpretation or argument by providing ''

gedanken A thought experiment is a hypothetical situation in which a hypothesis, theory, or principle is laid out for the purpose of thinking through its consequences. History The ancient Greek ''deiknymi'' (), or thought experiment, "was the most anc ...

'' experiments such as test cases or to fill in a weak CKB.

Functions

HYPO's method of creating an argument and justifying a solution or position has several steps. HYPO begins its processing with the current fact situation (cfs) which is direct input by the user into HYPO's representation framework. Once the user inputs the case, HYPO begins its legal analysis. The cfc is analyzed for relevant factors. Based on these factors HYPO selects the relevant cases and produces a case-analysis-record that records which dimensions apply to the cfc and which nearly apply (i.e. are "near misses"). The combined list of applicable and near miss dimensions is called the D-list. At this point the fact gathered module may request additional information from the user in order to draw a legal conclusion. Once all the facts are in the case-positioner module it uses the case-analysis record to create the claim

lattice Lattice may refer to: Arts and design * Latticework, an ornamental criss-crossed framework, an arrangement of crossing laths or other thin strips of material * Lattice (music), an organized grid model of pitch ratios * Lattice (pastry), an ornam ...

. This is a technique that organizes the relevant retrieved cases from the point of view of the cfc and makes it easy for HYPO to ascertain the most-on point cases (mopc) and to least on-point-cases. HYPO's arguments are 3ply, leading to the construction of the skeleton of an argument: it makes a point for one side, drawing the analogy between the problem and the precedent, responds with an argument for the opponent side, endeavoring to differentiate the cited case and citing other cases as

counterargument In reasoning and argument mapping, a counterargument is an objection (argument), objection to an objection. A counterargument can be used to Rebuttal, rebut an objection to a premise, a main contention or a lemma (logic), lemma. Synonyms of counte ...

s. Then it makes a final

rebuttal In law, rebuttal is a form of evidence that is presented to contradict or nullify other evidence that has been presented by an adverse party. By analogy the same term is used in politics and public affairs to refer to the informal process by w ...

, attempting to differentiate the counterarguments. The claim lattice also enables the HYPO-generator module to produce legally hypotheticals. With its use of dimension-based heuristics, the HYPO-generator does a

heuristic search In mathematical optimization and computer science, heuristic (from Greek εὑρίσκω "I find, discover") is a technique designed for problem solving, solving a problem more quickly when classic methods are too slow for finding an approximate ...

of the space of all possible cases. Lastly, the Explanation module expands upon the argument skeleton and provides explanation and justification for the different lines of analysis and cases found by HYPO.

An intelligent legal tutoring system

Legal expert systems are specifically designed to teach an area of law and are useful for

pedagogical Pedagogy (), most commonly understood as the approach to teaching, is the theory and practice of learning, and how this process influences, and is influenced by, the social, political and Developmental psychology, psychological development of le ...

purposes. Ashley's work was mainly concerned to build tools to help students understand legal reasoning. Explanation and argument are the bases of the case method used in many

professional school Professional development is learning to earn or maintain professional credentials such as academic degrees to formal coursework, attending conferences, and informal learning opportunities situated in practice. It has been described as intensive ...

s in the U.S., first introduced by the

Dean Dean may refer to: People * Dean (given name) * Dean (surname), a surname of Anglo-Saxon English origin * Dean (South Korean singer), a stage name for singer Kwon Hyuk * Dean Delannoit, a Belgian singer most known by the mononym Dean Titles * ...

of the

Harvard Law School Harvard Law School (Harvard Law or HLS) is the law school of Harvard University, a private research university in Cambridge, Massachusetts. Founded in 1817, it is the oldest continuously operating law school in the United States. Each class ...

Christopher Columbus Langdell Christopher Columbus Langdell (May 22, 1826 – July 6, 1906) was an American jurist and legal academic who was Dean of Harvard Law School from 1870 to 1895. Dean Langdell's legacy lies in the educational and administrative reforms he made to ...

in 1870. The

case method The case method is a teaching approach that uses decision-forcing cases to put students in the role of people who were faced with difficult decisions at some point in the past. It developed during the course of the twentieth-century from its origin ...

focuses on close readings of cases and principles; it involves students in pointed

Socratic dialogue Socratic dialogue ( grc, Σωκρατικὸς λόγος) is a genre of literary prose developed in Greece at the turn of the fourth century BC. The earliest ones are preserved in the works of Plato and Xenophon and all involve Socrates as the p ...

and makes strong use of hypotheticals (hypos). Thus, CATO (Aleven 1997) was a

research project Research is " creative and systematic work undertaken to increase the stock of knowledge". It involves the collection, organization and analysis of evidence to increase understanding of a topic, characterized by a particular attentiveness ...

to device and test an intelligent, case-based

tutorial A tutorial, in education, is a method of transferring knowledge and may be used as a part of a learning process. More interactive and specific than a book or a lecture, a tutorial seeks to teach by example and supply the information to complete ...

program for teaching law students how to argue with cases implementing the HYPO program.Ashley, K.D. and Aleven, V., Toward an Intelligent Tutoring System for Teaching Law Students to argue with cases, (1991) In Proceedings of the Third International Conference on Artificial Intelligence and Law, 42-52, Oxford, England Within the tutor system, Ashley and Aleven (1991) proposed to

leverage Leverage or leveraged may refer to: *Leverage (mechanics), mechanical advantage achieved by using a lever * ''Leverage'' (album), a 2012 album by Lyriel *Leverage (dance), a type of dance connection *Leverage (finance), using given resources to ...

an understanding of legal reasoning against the standard case-based tutoring methodology. What makes this tutoring system stand out is the additional levels of

abstraction Abstraction in its main sense is a conceptual process wherein general rules and concepts are derived from the usage and classification of specific examples, literal ("real" or "concrete") signifiers, first principles, or other methods. "An abstr ...

involved in its results. The system presents exercises, including the facts of a problem and a set of

on-line In computer technology and telecommunications, online indicates a state of connectivity and offline indicates a disconnected state. In modern terminology, this usually refers to an Internet connection, but (especially when expressed "on line" or ...

cases and instructions to make, or respond to, a legal argument about the problem. The student/user will have a set of tools to analyze the problem and fashion an answer comparing it to other cases. Instead of simply generating precedent cases, the system works to interpret student responses, comparing them against a list of possibilities and responding to student entries, for example, by citing counterexamples, and providing

feedback Feedback occurs when outputs of a system are routed back as inputs as part of a chain of cause-and-effect that forms a circuit or loop. The system can then be said to ''feed back'' into itself. The notion of cause-and-effect has to be handled ...

on a student's problem solving activities with explanations of correctness or giving further hints as to what may be wrong with evaluating a student's ability to perform legal reasoning and argument, examples and follow-up assignments by employing HYPO's model of case-based structure.

HYPO’s progeny

The quality of HYPO's results speak for themselves, in that a number of sequent legal reasoning systems are either directly based upon HYPO's mechanisms as in the case of Kowalski (1991), TAX-HYPO, precedent case-based system operating in the statutory domain of

tax law Tax law or revenue law is an area of legal study in which public or sanctioned authorities, such as federal, state and municipal governments (as in the case of the US) use a body of rules and procedures (laws) to assess and collect taxes in a ...

(Rissland and Skalak 1989), CABARET, a mixed-paradigm cases and rule system for the income tax law domain, (Skalak and Rissland 1992), CATO, IBP, developed for argumentation to make predictions based on argumentation concepts (Brüninghaus and Ashley 2003), or their creators at least pay homage to HYPO in their discussions (Henderson and Bench-Capon 2001Henderson, J. & Bench-Capon, T, Dynamic arguments in a case law domain, (2001) Proceedings of the 8th international conference on Artificial intelligence and law, 60-69.).

References

External links

* Aleven, V.

(2003) Artificial Intelligence 50, 183–237 * Report Abel Hinkf6230 Cbr

Hypo Km Health Informatics Report * Ashley, K.D.

Modeling Legal Argument: Reasoning with cases and hypothetical, MIT Press, Cambridge, 1987. Based on Ashley's Phd Dissertation COINS Technical Report No. 88–01 Expert systems Argument technology Legal software