Bartosz Brożek 1 The Logic of Legal Negotiations O ne can imagine various applications of logic in legal negotia- tions. For example: logic constitutes a standard of rational think- ing, and the ability to recognize typical logical mistakes may be quite useful in any negotiating. 2 In this essay, however, I would like to pose a different, more fundamental question: what are the logical peculiar- ities of negotiations in general, and legal negotiations in particular? I will argue that any attempt at reconstructing the structure of the nego- tiation process leads to the rejection of classical logic and generates the need to use nonstandard formal tools, such as paraconsistent and nonmonotonic logics. I will also try to substantiate the claim that the law does not inluence the logical structure of negotiations directly, although some aspects of this extra-logical inluence can be formally reconstructed. 1. The Logic of Discussion Let us imagine the process of negotiating the purchase of a paint- ing by a famous artist. Both the Seller and the Buyer believe that the work is not a forgery. However, the Seller claims that it is an out- standing work of the artist, while the Buyer thinks it is quite aver- age. In consequence, the Seller claims that the painting is worth more 1 Department for the Philosophy of Law and Legal Ethics, Jagiellonian University, Kraków; Copernicus Center for Interdisciplinary Studies, Kraków. 2 Cf. J.E. Van Vleet, Informal Logical Fallacies, University Press of America, Lan- ham 2011.