Degrees of support and possibility are the central formal concepts in the theory of probabilistic argumentation Probabilistic argumentation (Haenni, 2005a, 2009; Haenni et al., 2000; Kohlas, 2003). This theory is driven by the general idea of putting forward the pros and cons of a proposition or hypothesis in question. The weights of the resulting logical arguments and counter-arguments are measured by probabilities, which are then turned into (sub-additive1) degrees of support Support and (super-additive) degrees of possibility. Possibility