Implementation of Expert Systems as
an Aid to Legal Decision-Making
Antonio A. Martino
If the solution is to be found for any hypothetical or real legal case, we need to know what "the law" provides for in those cases. In the present epoch, this knowledge is mainly contained in legal texts and, therefore, a detailed analysis of these texts (perhaps computer-assisted) is an aid to legal decision-making that cannot be ignored.
To begin, "law" must be defined and decisions described. The concept of "law" is too complex to be dealt with completely in this chapter. It is sufficient to define it here as synonymous of "legal order" capable of being recuperated through legal sources. And what decisions are dealt with? Any whatsoever: those of a judge, a practicing lawyer, a civil servant, a legal academic, or a legislator.
An appropriate automated analysis of legal sources constitutes a rational reconstruction of them, identifies and organizes them in hierarchically classified sources, makes it possible to check on their completeness and consistency, and, above all, allows legal consequences to be reached. In short, the transformation of a disordered set of sources into a complete and ordered set permits all the techniques by which lawyers reach legal consequences from these sets to be applied. These are operations that, to a large degree, can be entrusted to the computer and can, therefore, aid in legal decision-making through the exhaustive analysis of the legal sources relating to the case and its consequences.
The picture drawn in this chapter appears to be a typical view of continental European law. Seemingly, the English system of precedents leans more toward induction than deduction, but, in fact, even in English legal reasoning there is an important deductive part. It is based on reasoning by examples, and it is a process divided into three separate steps, characterized by the theory of prece-