The importance of the senses in Epicurean thought cannot be overstated. The alpha and omega of its empirical epistemology, a touchstone underlying various aspects of its linguistic theory as well as many of the more overtly literary features of Lucretiusʼ De rerum natura, and, more debatably, the basis of its ethical system, they have often been studied as such. Along somewhat different, though related, lines: in scholarship on Epicurean philosophy of mind there has been a growing recognition of the need to (re)account for the material physiological processes involved in all ʻpsychologicalʼ phenomena - not just those directly related to the swerve. With respect to the topic at hand, the work of Sedley (1989), Annas (1992), Fowler (1997), Konstan (2008) and Gill and Glidden (varia), among others, is particularly noteworthy. Building on that recognition, this paper assesses the extent to which sensory perception was regarded - by one of our most important Epicurean sources - as a cognitive faculty, and who or what was deemed to possess it.
De rerum natura contains by far the most detailed and complete of the surviving Epicurean accounts of the physiological aetiology of sensory perception. Insofar as is possible, and with due attention to the limitations of this approach, this account is treated as Lucretiusʼ own self-contained representation of Epicurean doctrine, rather than as a means of getting back to Epicurus himself. Evidence from other authors, such as Epicurus, Philodemus, and Diogenes of Oenoanda, is also brought to bear on it. The paper thus analyzes Lucretiusʼ exposition of the emergence of the faculty of sensus and its primary manifestations. In the process, it furthers our knowledge of the relationship between mind, body, and soul, as understood by Lucretius.
The paper argues that, for Lucretius, the ʻmindʼ and ʻsoulʼ constitute a single material entity which is both physically involved in the perceptions of the so-called ʻfive sensesʼ and, in the context of the rest of the living body, sensory in-and-of itself - particularly with respect to especially subtile simulacra and emotions. The paper also shows that the faculty of sensus coexists with life itself and represents a fundamental continuity - both physiologically and cognitively - between human and animals. Examples of health, illness, and survival mechanisms in the text provide some of the key evidence for these arguments. The result is a three-fold concept of sensus. This concept encompasses the range of interpretations of two contentious terms in scholarship on Epicureanism: αἴσθησις and παθῆ. (Cf. Solmsen 1961a, Striker 1977, Furley (1993), Konstan (especially) 2008, Asmis 2011). The very breadth of the concept of sensus suggests its significance in Greco-Roman thought.
The context of contemporary developments in medical science is not irrelevant to this analysis, as shown, for example, by Solmsen (1961b) and Annas (1992). It is likely that Epicurus worked out his ideas about the senses before the discovery of the nerves, when empirical knowledge of anatomy in the Greek world was still largely restricted to the dissection of animals and medical treatment of human wounds. It is not inconceivable that Lucretiusʼ particular synthesis and reworking of Epicurusʼ ideas in part constitute, or at least reflect, some dialogue with the later developments. Furthermore, support emerges over the course of the paper for the claim that the Epicurean solution to, among other things, the mechanism of sensory perception was remarkably forward-thinking. Mutatis mutandis, this relatively original account approaches - both apparently and functionally - the modern concept of the nervous system, albeit one with its centralized part in the breast
Aisthêsis: Sense and Sensation in Greco-Roman Medicine