OUT OF TOUCH: PHILOPONUS AS SOURCE FOR DEMOCRITUS Jaap Mansfeld 1. Introduction The view that according to Democritus atoms cannot touch each other, or come into contact, has been argued by scholars, most recently and carefully by C.C.W. Taylor, especially in his very useful edition of the fragments of the early Atomists.1 I am not concerned here with the theoretical aspect of this issue, that is to say with the view that the early Atomists should have argued (or posthumously admitted) that atoms cannot touch each other because only the void that separates them prevents fusion. I wish to focus on the ancient evidence for this interpretation. Our only ancient source for this view happens to be Philoponus; to be more precise, one brief passage in his Commentary on Aristotle’s Physics (fr. 54c Taylor) and two brief passages in that on Aristotle’s On Generation and Corruption (54dand54eTaylor~67A7 DK). These commentaries, as is well known, are notes of Ammonius’ lectures, with additions by Philoponus himself. Bodnár has argued that this evidence is not good enough, because all other ancient sources, in the first place Aristotle, are eloquently silent on a ban on contact; what we have here therefore are ‘guesses of Philoponus, which are solely based on the text of Aristotle’.2 Taylor admits the force of this objection, but sticks to his guns: ‘perhaps’, 1 Taylor (1997) 222,(1999) 186–188, 192–193,(1999a) 184, cf. the discussion in Kline and Matheson (1987) and Godfrey (1990). On the problems related to the assumption that attraction plays an important part see further the cautious remarks of Morel (1996) 422–424, who however does not take into account the passages in Philoponus which suggest that atoms cannot touch each other. 2 Bodnár (1998) 45–51,esp.49–50.Cf.Tarán(1969) 12: ‘many times what Asclepius and Philoponus [in their commentaries on the Introduction to Arithmetic] quote or para- phrase from ancient authors is probably only based on the text of Nicomachus that Ammonius [cf. below, n. 8] must have had in front of him while he lectured’]. Against Taylor see also Haspers (1999). 278 jaap mansfeld he says, the Atomists held that contact was impossible;3 moreover the implication (!)4 of Philoponus’ contention, viz. that the “basic physical forces are attraction and repulsion”, works quite well. There is also solid evidence that the principle of ‘like to like’ played an important part in Democritus’ physics.5 Atomic motion, such as the formation of compounds consisting of atoms of the same shape and more or less the same size, may therefore be explained by attraction, and attraction also explains why they stay together.6 But how reliable is Philoponus as a source for Democritus, that is to say: what were his sources for Democritus’ doctrines, and how did he use them? I have looked at all the references to the early Atom- ists in his genuine works. The outcome of this inspection is that he7 either did not have Democritus’ works in the field of physics or at any rate did not bother to look things up in those works that may have been available. The fact that Simplicius, who is fond of quot- ing from Presocratic texts, does not do so for Democritus and Leu- cippus makes the conclusion that by the time of these late commen- tators the corpus Democriteum had been lost practically inescapable. The only kind of information on early Atomism used by Philoponus turns out to be what is found in the treatises of Aristotle, what (presum- ably, and as I shall argue) he was able to find in other commen- taries on these treatises or what had percolated from these commen- taries to his own days, and perhaps also what was to be found in the Placita literature. The unparalleled contention that atoms cannot touch each other is an exegetical manoeuvre, and one needs to look care- fully at the contexts where it occurs. Most importantly, we shall find that elsewhere Philoponus also states that atoms do bump into each other. 3 Taylor (1997) 222,(1999) 187,(1999a) 184. 4 Philoponus does not mention either attraction or repulsion. 5 Cf. also below, section 5. 6 Taylor (1999) 187f., 193. That atoms when combined or entangled may stay together simply as long as no external force breaks up the combination is not taken into consideration. See the famous fragment from Aristotle’s On Democritus,fr.208 3R (~ 44aTaylor,68A37 DK) ap. Simpl. in Cael. 295.18–20: ‘he thinks that the atoms hang on to one another and remain together for such an amount of time (7π τ σ -τ ν _ν ρν ν σ!ν ατ!ν ντεσαι … κα συμμνειν) until some stronger necessity from the surroundings thoroughly shakes the compound and disperses it’. 7 As well as his master Ammonius, to whom I shall refer no more: the name Philoponus is short for the commentaries on Aristotle that are at issue..