The disclaimer "sub correctione aliorum", frequently used in Latin texts, highlights the centrality of notion of error in medieval science. But beyond the rhetorical aspect, what does it reveal in terms of epistemology and morals? I take it that, in the 13th and 14th centuries Latin intellectual world, it supports a conception of human knowledge developed through making and correcting mistakes, grounded on a moral view of the necessity of collective labour unfolding over time.  Medieval science in the Latin world thus appears as a progressive and collective endeavour, requiring an appropriate epistemology. Given the prominence of Aristotle in the intellectual production at the time, one could easily assume that Aristotelian epistemology was key. However, Aristotelian epistemology is often viewed as the promotion of an ideal, eternal and certain science, and not as a flexible body of doctrine, capable of accommodating gradual changes and corrections. It also seems then calls the nature of the errors involved and the possible strategies for remedying them vary according to the discipline. Therefore, if the centrality of the role of error in some areas of medieval knowledge is established, the epistemic norms involved may also vary, calling for a reassessment of the historian’s views on medieval science.

Taking the astral disciplines (astronomy, astrology and cosmology) as my field of investigation, I will present three case studies which challenge these views on Latin Medieval Science and make it appear less dogmatic and more like a collective and tentative venture of dealing with errors.

I will first present a case of identification and correction of errors in astronomy, through the lens of the 13th c. astronomer William of Saint-Cloud’s works. Then, I will discuss an interesting statement by 14th c. John of Murs, both natural philosopher and astronomer, that intertwines scientific argumentation and the morality of researchers. Finally, I will tackle the question of error in interdisciplinary debates through the example of a fierce debate over astrology between a philosopher (Nicole Oresme, 14th c.) and an astronomer (Giovanni da Fondi, 15th c.), to discuss a final issue: when confronted with polemical material and arguments debated as erroneous by Medieval authors based on their different backgrounds and set of values, how should historians, philosophers and editors react?