Legal reasoning on the requirements and application of law has been studied for centuries, but in this subject area the legal profession maintains predominantly the same stance it did in the time of the Ancient Greeks. There is a gap between the standards of proof, one which has been always demonstrated by percentages and in terms of the evaluation of these standards by percentages by mathematical or statistical methods. One method to fill the gap is Bayes theorem that describes an (...) event’s probability based on conditions that might be related to an event. Bayes theorem can help to establish or confirm a relation between facts and rules if there is sufficient other evidence that connect a party in a procedure with a considered legal action. (shrink)

Behind the pendulum-like regulatory swings between interventionism and laissezpasser that are nothing but the results of changing contexts are the legal principles as their denominators and connectors. Legal principles guide explanations and give paths that a decision maker must not circumvent. In the enhanced dynamic environment that is based more on risk and prediction than solely ex post adaptation they cannot cope with the more numerous information and communication channels. Principles can be more fully embraced with the help of more (...) systematically-elaborated reality. Without clear steps needed for the formation of principles talks about the regulatory impact assessment, risk management, evidence-based approach and other regulatory notions are only a stuff for filling the paper lines than the real tools for the management of reality. (shrink)

The principle of proportionality is seen as the highest peak of structural, logical thinking that enables balancing between constitutional principles and their interferences. So far, Alexy's weight formula has been the most advanced approach in structured balancing of proportionality stricto sensu, while this paper shows it as still too subjective. Despite judicial tests—or different, manifestly inappropriate reasonableness tests—proportionality stricto sensu hides some form of the jumping-to-conclusions bias, because the inference is made through a subjective lens. The paper presents structured legal (...) balancing (and hence reasoning) based on Bayes’ theorem. This paper, based on the connection between probability and hypothetical legal norms, transfers the four-part structure of proportionality into the relevant four-part structure of the Bayes tree. This transfer shows the first as flawed due to its failing to consider means that can have the same effects as the considered ones. Only by inclusion of the latter can the total probability of a considered case be established. Numerical proportionality à la Bayes can be further improved through the use of public-value weights that are obtained from surveys or online communities of people giving weights in the real time (collective wisdom). The Bayesian approach can also be used in adjudication as a control in assessing judicial standards in use. (shrink)