Subjective Logic

Subjective logic is a type of probabilistic logic that allows probability values to be expressed with degrees of uncertainty. The idea of probabilistic logic is to combine the strengths of logic and probability calculus, meaning that it has binary logic’s capacity to express structured argument models, and it has the power of probabilities to express degrees of truth of those arguments. The idea of subjective logic is to extend probabilistic logic by also expressing uncertainty about the probability values themselves, meaning that it is possible to reason with argument models in presence of uncertain or incomplete evidence. In this manuscript we describe the central elements of subjective logic. More specifically, we first describe the representations and interpretations of subjective opinions which are the input arguments to subjective logic. We then describe the most important subjective logic operators. Finally, we describe how subjective logic can be applied to trust modelling and for analysing Bayesian networks. Subjective logic is directly compatible with binary logic, probability calculus and classical probabilistic logic. The advantage of using subjective logic is that real world situations can be more realistically modelled, and that conclusions more correctly reflect the ignorance and uncertainties that necessarily result from partially uncertai