Peer review and knowledge by testimony in mathematics Christian Geist, Benedikt Löwe, Bart Van Kerkhove Abstract: The peer review process has been the topic of many studies in the medical sciences, but not so in mathematics. Given that mathematicians refer to results from the literature without checking the proofs in detail, it is interesting to see how the mathematical refereeing process affects the epistemic certainty of this type of mathematical knowledge by testimony. We give a description of the mathematical refereeing process and some results of empirical studies.