Eigenlogic and probabilistic inference: when Bayes meets Born

This article shows how inference is treated within the context of Eigenlogic projection operators in linear algebra. In Eigenlogic, operators represent logical connectives, their eigenvalues the truth-values and the associated eigenvectors the logical models. By extension, a probabilistic interpretation is proposed using vectors outside the eigensystem of the Eigenlogic operators. The probability is calculated by the quantum mean value (Born rule) of the logical projection operators. We look here for possible connections between the Born rule in quantum mechanics and Bayes' theorem from probability theory and show that Eigenlogic offers an innovative approach to address the probabilistic version of logical inference (material implication) in a quantum context. This article is part of the theme issue 'Quantum theory and topology in models of decision making (Part 2)'.