The aim of this paper is to decipher Lucretius’ cryptic remark about touch at DRN 2.434-5.
At 2.398-443, he defends his thesis that atoms vary in shape: the variety of ways in which any single sense can be affected is best explained by the hypothesis of differently shaped atoms affecting it. The argument works its way through the five senses, ending with touch, which is itself marked by a surprising rhetorical fanfare: tactus enim, tactus, pro divum numina sancta / corporis est sensus ... (434-5). What does this mean? The question has received virtually no discussion, even in U. Schoenheim, ‘The place of tactus in Lucretius’, Philologus 1966. Commentators assume Lucretius to mean that touch is the fundamental sense: all sensation, even by the other senses, is ultimately reducible to touch. After rejecting this and some other possible interpretations, I propose that the emphasis of the passage is, rather, as follows: when the body itself (as distinct from eyes, ears etc.) perceives something, the sense responsible for this is always touch, regardless of whether it is perceiving something external or internal to the body.
A problem for this interpretation is to account for enim (434), since 434-5 is meant to explain why fire and frost affect our senses differently (431-3). Why should the fact that touch is responsible for all the sensing the body itself does, internally and externally, be invoked to explain an experience that appears to involve a purely external application of touch, namely sensing fire and frost? The answer, I argue, lies in tactus uterque (433). This has been unanimously understood to refer back to the duality just mentioned, our sensation by touch of (a) fire and (b) frost. Rather, I argue, it refers forward to the duality that is about to be introduced, (a) external touch, (b) internal touch. We can infer the different atomic structures of fire and frost by external touch – they feel different when we touch them – but also by internal touch, the sense by which we become aware of feeling hot (when heated by fire) or cold (when cooled by frost). In support, I cite [Philodemus, De sensibus], PHerc. 19/698, col. XXIX, ed. A. Monet, Cron. Erc. 26, 1996, 27-126): touch ‘perceives both hot and cold, both within itself and adjacent to itself’. I then use this dual touch theory to relate the passage to the broader Hellenistic concept of ‘internal touch’, which makes us aware of internal changes. (The connection is well noted by E. Asmis, Epicurus’ Scientific Method, 1984, 105 n. 2, albeit without using it to reinterpret the passage.)
Returning to 2.434, I propose that instead of the repetition of nominative tactus, whose emphatic ring has deflected readers from seeing where the real weight of the sentence lies, we read the second tactus as genitive: when the body itself senses something, this is a ‘touching of touching’ – meaning awareness, by the tactile sense, of direct corporeal contact, whether this latter be of external or internal origin. The exclamation pro divum numina sancta would highlight the paradoxical expression, quite possibly echoing Epicurus’ own characteristic πρá½ς τÏŽν θεá¿¶ν.