Everyday life reasoning and argumentation is defeasible and uncertain. I present a probability logic framework to rationally reconstruct everyday life reasoning and argumentation. Coherence in the sense of de Finetti is used as the basic rationality norm. I discuss two basic classes of approaches to construct measures of argument strength. The first class imposes a probabilistic relation between the premises and the conclusion. The second class imposes a deductive relation. I argue for the second class, as the first class is (...) problematic if the arguments involve conditionals. I present a measure of argument strength that allows for dealing explicitly with uncertain conditionals in the premise set. (shrink)

In this contribution the prototypical argumentative patterns are discussed in which pragmatic argumentation is used in the context of legal justification in hard cases. First, the function and implementation of pragmatic argumentation in prototypical argumentative patterns in legal justification are addressed. The dialectical function of the different parts of the complex argumentation are explained by characterizing them as argumentative moves that are put forward in reaction to certain forms of critique. Then, on the basis of an exemplary case, the famous (...) Holy Trinity case, the way in which the U.S. Supreme Court uses pragmatic argumentation in this case is discussed by showing how the court instantiates general prototypical argumentative patterns in light of the institutional preconditions of the justification in the context of the specific case. (shrink)