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Dreaming and the Illusion of Reality in the Aristotelian Tradition

Project leaders: F. Radovic & C. Thörnqvist

The Problem

Dreams include a special case of misrepresentation, since dreams typically present how things are in the world, in a perception-like way, but misrepresent what is the case. Unlike instances of sporadic misperception and systematic perceptual illusions, the dreamer is usually fully deluded about the true nature of his present mental activity. Dreams typically enter philosophy in the form of a sceptic challenge, i.e., whether a subject can determine if his current experience is a dream or not. In De Insomniis, Aristotle shows no direct interest in this well-known epistemic problem. By contrast, he attempts to explain how dreams emerge, why dreams appear in the guise of perception and what causes the dreamer to be deluded during dreaming.

Aristotle’s naturalistic approach to dreaming is quite original and anticipates recent philosophical approaches[4]. Even so, Aristotle’s account is poorly studied and the vast tradition of his commentators is even less explored. There are a large number of ancient and medieval commentators on De Insomiis, De Somno, De Anima and related writings – texts that are still unedited and therefore still inaccessible for any modern scholar who lacks the classicist’s competence in reading and reconstructing texts. Our sub-project aims at a careful articulation of the theories found in Aristotle’s work and the later interpretations and developments of these theories on dreaming in the ancient and medieval commentators by investigating from a philosophical-philological perspective how the works studied answer the following questions:

  1. How are dream-appearances produced?
  2. Why is the dreamer deluded during dreaming?
  3. In what respect, if any, are dream-appearances similar to perceptual states?
  4. What role does resemblance between dream awareness and perceptual awareness play in the explanation of an illusory sense of reality?

For Aristotle’s theory of dreaming, De Insomniis and De Anima comprise a fairly large collection of arguments and observations that may be used in order to reconstruct some answers to the selected questions. However, there are also important tensions and obscurities in the texts that render a consistent interpretation difficult. In addition, Aristotle’s analysis of dreaming comprises complex issues still regarded as highly problematic within contemporary philosophy. In the case of Aristotle’s De Insomniis, some attempts[5] have been made at clarifying some of the problems in the text, but so far, no comprehensive analysis of Aristotle’s theory of dreaming has been performed. The following are just a few out of many questions that need to be answered.

Main Questions

Aristotle argues that perceptual sense impressions may persist in the absence of external objects. This assumption is supported by a number of observations, for instance, the occurrence of after-images and other delayed perceptual effects. It is further argued that dreaming is the work of imagination and that perception, as well as judgement fail to hook up to the external world during sleep. Nevertheless, Aristotle assumes a close connection between imagination and perception, but what is the nature of this connection, and more precisely how does judgement (doxa) relate to imagination (phantasia)? To complicate matters further, Aristotle allows the occasional possibility of perception of external objects during sleep. Perception during sleep should obviously not be understood as dreaming since dream appearances lack the appropriate temporal and causal connection to external objects. Moreover, sometimes the sleeper may recognise that he is actually asleep and that appearances within him do not correspond to reality (the phenomenon of lucid dreaming). Precisely what is going on in such cases?

The main purpose of the sub-project will be to systematically reconstruct Aristotle’s theory of dreaming and use the result as a basis for an analysis of the later development. The main focus will be on the Latin medieval tradition of the Parva Naturalia and especially on the at least ten so far un-edited anonymous Latin commentaries mentioned above (2.3.3). However, any study of the medieval development will have to take the Greek tradition into careful account and a comparative analysis of the ancient and Byzantine Greek and the Mediaeval Latin reception of the Parva Naturalia will be an important task in the project. Since the Mediaeval Latin tradition and especially the anonymous works have been so poorly studied and since a careful inventory of relevant un-edited texts still remains to be made, it is not possible until such an inventory exists to single out the medieval texts which will be edited within the sub-project. The result of the project – i.e. the reconstruction of Aristotle’s theory of dreaming and illusion and the comparative analysis of the interrelation of the ancient commentators and the Mediaeval Latin tradition aided by critically edited medieval works which so far have been virtually unknown and inaccessible to modern readers, will be presented in a monograph. In addition, at least one of the anonymous Latin commentaries on the Parva Naturalia will be critically edited as a whole.

Our sub-project will thus not only make a significant contribution to the interpretation of Aristotle’s views on dreams and illusion of reality and their ancient, Byzantine and Mediaeval Latin reception; it will also shed light on the development of theories of intentionality and perception, which in turn connects to issues involving concepts and concept formation.


2013: During the first year, Radovic will work on the reconstruction of the theory of dreaming in Aristotle’s De Insomniis and other relevant Aristotelian works, whereas Thörnqvist collaborates with the editorial group and publishes in collaboration with Ebbesen the abovementioned catalogue of 13th and 14-century Latin commentaries on Parva naturalia

2014–2016: Radovic and Thörnqvist collaborate in (a) a philosophical analysis of the Latin commentators and in (b) a comparative analysis of these and the ancient Aristotelian commentators. One or several of the most important un-edited medieval sources are singled out to be edited by Thörnqvist and jointly commented by Radovic and Thörnqvist.

2017: The manuscript of the monograph (with the title Aristotle and his commentators on Imagination and Dreaming or similar) is prepared for publishing. The work on the edition and commentary continues.

2018: The monograph is published. The manuscript of the edition is prepared for publishing.

2019: The critical edition is published. Thörnqvist is responsible for organizing the preparations of the manuscript of the common volume on the Latin tradition whereas Radovic leads the joint work on the sections on sense and sensory knowledge in all three volumes.

Relation to Other Sub-Projects

Our project is sure to benefit from Ierodiakonou, Bydén and Mora-Márquez. The interconnections with Arabic Aristotelianism are still to be investigated. Furthermore, our project directly supports Mora-Márquez, leading as it does to the formation of phantasmata, and Fink as to the nature of dreams among Latin Aristotelians.

Page Manager: Andreas Ott|Last update: 3/18/2013

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