Clues of observations practices Astronomy and natural sciences in late medieval Europe (Latin, Arabic and Hebrew)

3.12-5.12, Paris Observatory

Org.: José Chabas, Matthieu Husson, Richard Kremer, Laure Miolo


A wealth of historical and philosophical studies of scientific observation has produced valuable methodological insights and a better understanding of different practices of observation in numerous historical contexts (e.g. L daston, 2011, K. Park 2011). Other studies have also demonstrated the links between observations and experiments and explored the medieval terminology of these interrelated notions, their connection to different kinds of reasonnings and computations (D. Jacquart, 1996). However, historical analysis of observation in pre-modern scientific traditions remains a complex task for the historian because of the difficulties to escape the various modern conceptions that flourished at least since the 18th centuries and the ideological weight attached to the study of the place of observation in a given scientific tradition. These general issues tends to obscure the historical sources themselves and the historian of pre-modern scientific traditions is therefore often faced with the fundamental problem of identifying clues of observation in them.


This situation is especially acute in the history of astral sciences where the evolving relations of observations, instruments, computations, and theory are central in particular to mathematical astronomy. As one of its important general aims regarding astronomical practices, ALFA seeks for a better understanding of the different kinds of observations practiced in the Alfonsine traditions, their mutual relations and their contexts. This enhanced understanding is a necessary step toward a survey of astronomical observations including, when pertinent, elements such as: dates, locations, actors involved, phenomena observed, methods used, or epistemic aims. Most Alfonsine astronomers were trained in arts faculties to natural philosophy and intermediate sciences (optics, music, meteorology…) with some of them pursuing their studies in medicine or theology. Moreover, some alfonsine astronomers wrote and worked in disciplines outside mathematical astronomy (e.g. Jean des Murs, Prodoscimo Beldomandi, …) and many manuscripts reflect this diversity of practices. Thus, it seemed important for us, in an initial approach to the topic, to include also these other disciplines as ideas, practices, ways of recording observations might well carry over from one discipline to another. In the same line of thought it essential to include sources in Hebrew and Arabic produced in Europe during the late medieval and early modern period or shortly before in order to trace transmission, interactions, overlap and contrast.


This workshop attempt to explore these issues by focusing first on clues of observation in the sources. In this way we hope to broaden the scope of what we are able to recognize as an observation in late medieval and early modern scientific practices and thus to build an enhanced understanding of how observations of various kinds nourished different sciences during these periods. This general aim can be addressed through multiple angles. These includes at least the following three broad categories:

  • Documentary aspects and material culture of observations practices: What are the writing format of observation statements? How are observation reports materially integrated in larger textual structures, in curriculum? Can we find clues of observations beside the various kind of direct observations statements? In other words: can we identify indirect clues of observations in our sources? In the opposite: are all observation report truly reporting an observation? If case of “fake” observation report are found what does this mean for observation and its status? What kind of instruments, in a broad sense (e.g. including manuscripts), could be used in relation to observation? How do we know about these instruments, (e.g. through specific kinds of text dedicated to them, through archeological remains, through observation ‘records’ including chronicles, almanac or miniatures)? How are diagrams or numerical tables used in observation or in reporting observations?
  • Temporality and collective aspects of observations practices: Are there kinds of observations made alone and others made in group? In case of group what are the roles of the different actors involved? How is information about the observation shared within the group? What is the temporality of observation? How does this affect the collective aspect of observation (in astronomy observation can often range on very long time span)? How does this affect the way information from observation are reported and transmitted? Who owned instruments, individuals, institutions? Were they made ad hoc or the result of a stabilised standardised production? Are they object of prestige or social symbols of specific kind of knowledge (e.g. astronomer are very often portrayed with an astrolabe on medieval miniatures)? What were materials employed for constructing instruments? What were their cost?
  • Epistemological aspects of observations practices: What are the phenomena observed and defined by different kinds of observations? How are observations made visible in scientific reasoning of different sorts (computations, predictions, deductions, diagnosis)? How is observation used differently to legitimize the scientificity of a given discipline, its boundary, its methodology? How do instruments take part in various types of observations and contribute to shape them in theoretical ways? More fundamentally, what kind of skills are required to manipulate these instruments? What are the limitations of instruments? Is there a codification of observation practices with instruments?


In order to foster awareness about evidences of observations practices along these lines we will seek to set an open discussion between specialists of sciences, technologies and philosophies but also arts historians, historian of material culture interested in this endeavour. This discussion shall be articulated around specific case studies presented by the different contributors that address some of the question listed above or related ones.