Effects of the Choice of Arbitration Ex Aequo et Bono - Chapter 2 - International Arbitration Ex Aequo et Bono/Amiable Composition
2.1 SUBSTANTIVE LAW
2.1.1 Structure of the Decision Ex Aequo et Bono
Legal decisions follow the famous syllogism according to which the rule is the major premise and the facts are the minor premise. Normally, such syllogism is described as follows: “if A is, then B must be,” in which “A” represents a fact and “B” the legal consequence set forth by the rule. Generally, the rule is a prius with regard to the fact.
In the decision ex aequo et bono, the positive rule is not necessarily used. The arbitrator has the option not to resort to the rule to decide. Therefore, the classical syllogism does not correspond (or at least does not necessarily correspond) to the form of the decision.
Several authors have engaged in the study of the structure of the decision ex aequo et bono and are not unanimous in their conclusions. This chapter is intended to present the different views on the logical structure of the decision ex aequo et bono (or its “decision-making mechanism”), as well as some attempts of imputing a value content that transcends the only vague reference of “sense of justice” of he who decides. After a critical presentation of such positions, the author intends to demonstrate that the essential element of the decision ex aequo et bono is the freedom with regard to pre-established methods.
 See, among several others, Larenz, Karl. Metodologia da ciência do direito. 3. ed. Lisboa: Fundação Calouste Gulbekian, 1997. p. 380. Also Reale, Miguel. Lições preliminares de direito. 19. ed. São Paulo: Saraiva, 1991. p. 93 et seqq.
 Or, according to the formulation of Larenz (ibidem, p. 381): “I denominate that logical figure a ‘syllogism for the determination of the legal consequence.’ In it, the major premise is constituted by a complete legal proposition and a minor premise by the subordination of a situation of a concrete fact, such as a ‘case,’ under the provision of the legal proposition. The conclusion affirms that for that de facto situation the legal consequence mentioned in that legal proposition is valid.”
 Among others, Ascensão, José de Oliveira. Entry “Eqüidade.” Enciclopédia Saraiva do Direito. São Paulo: Saraiva, 1977.