1. See Wojciech Zaluski, Evolutionary Theory and Legal Philosophy (2009); 5 Studies in Philosophy of Law: Law and Biology (Jerzy Stelmach, Bartosz Brożek & Marta Soniewicka eds., 2011).
2. This follows from inequalities and . Such inequalities entail that , i.e., that . Since we know that the α's utility is inferior to 0, α being disproportionate, and that the β's utility is inferior to α's, it follows that also β's utility is inferior to 0, namely, that also β is disproportionate.
3. On the idea of fit, see Ronald Dworkin, Law's Empire 225-75 (1986). On the connection between value-based reasoning and the interpretation of rules or the determination of their priorities, see Trevor Bench-Capon & Giovanni Sartor, A Model of Legal Reasoning with Cases Incorporating Theories and Values, 150 Artificial Intelligence 97 (2003)
4. Henry Prakken, An Exercise in Formalising Teleological Case-Based Reasoning, 10 Artificial Intelligence & L. 113 (2000).
5. On the need to complement proportionality with deontological considerations, see Mattias Kumm, Political Liberalism and the Structure of Rights: On the Place and Limits of the Proportionality Requirement, in Law, Rights and Discourse: The Legal Philosophy of Robert Alexy 131 (George Pavlakos, ed., 2007). Such deontological worries, however, can be addressed, I would argue, by applying proportionality analysis at a higher level, namely, at the level of the justification of adopting an action-rule.