Christina Thörnqvist

Aristotle's De memoria et reminiscentia is the oldest surviving systematic study of the nature of human memory. Forming part of Aristotle's other minor writings on psychology that were intended as a supplement to his De anima and known under the collective title Parva naturalia, Aristotle's De memoria et reminiscentia gave rise to a vast number of commentaries in the Middle Ages. The present volume offers new knowledge on the medieval understanding of Aristotle's theories on memory and recollection across the linguistic traditions including the Byzantine Greek, Latin and Arabic reception.

The articles in this issue are a selection of the papers presented at the conference Knowledge as Assimilation, held at the University of Helsinki on 9-11 June 2017. The conference was the result of a collaboration between two research groups that have been established in Finland and Sweden from 2013 onwards: the research project Rationality in Perception: Transformations of Mind and Cognition 1250-1550, funded by the European Research Council and hosted by the University of Helsinki, and the research programme Representation and Reality: Historical and Contemporary Perspectives on the Aristotelian Tradition, funded by the Riksbankens jubileumsfond and located at the University of Gothenburg.

_ Source: _Volume 54, Issue 4, pp 286 - 310 In _De somno et vigilia_, Aristotle states that sleep is an incapacitation of the first sense organ that occurs when the capacity for sensation has been exceeded. In the same treatise, however, Aristotle also mentions the phenomenon of motion and other waking acts performed in sleep and claims that sense perception is a necessary condition for such acts to occur. When the medieval exegesis on the _Parva naturalia_ evolved in the thirteenth century, how Aristotle’s remark on motion in sleep could be reconciled with his definition of sleep as an incapacitation of the senses became one of the most frequently discussed problems. This article analyzes the theories on this subject in the most influential commentaries on Aristotle’s treatises on sleep and dreaming in the thirteenth century.