Published online by Cambridge University Press: 23 December 2013
Empedogles' simile of the clepsydra (DK6 31B100) is a crucial document for historians of ancient science. It has been much discussed, and often quoted in evidence, in spite of formidable differences of opinion about its significance. ‘Empedocles undertook an experimental investigation of the air we breathe’ (B. Farrington). ‘The star example of a physical “experiment” in the natural philosophers, the clepsydra, was not an experiment at all, in the proper sense of the word’ (G. Vlastos). ‘All Empedocles did was to draw the explicit inference: “the vessel cannot be simply empty: the air in it cannot be nothing at all”. He did not invent the clepsydra in a laboratory’ (F. M. Cornford). The simile ‘ha tutto il carattere di una esperienza scientifica’ (A. Traglia). Now whether the fragment describes an experiment or not, it is certainly a simile, and the first step must be to understand the force of the simile. It is possible, in my view, that the differences of opinion about the fragment spring from various misunderstandings of the simile; and I propose in this article to offer an explanation of its details which I think is new and which may enable us to form a clearer picture of its place in the history of science.
1 I have set out this argument in full in view of a curious attempt by Traglia, Antonio in his recent book Studi sulla Lingua di Empedocle (Bari, n.d., p. 25 n.)Google Scholar to save Aristotle from this mistake. All is simple, Traglia maintains, if we realise that the crucial sentence is to be translated: ‘Affirmando … (v. 4) Empedocle pensa di parlare anche della respirazione nasale e della respirazione vera e propria.’ A glance at thetext of Aristotle will show that this is a misunderstanding of the typography of DK: Aristotle does not quote v. 4 here.
2 See the illustrations in Professor Last's article, or in Guthrie, W. K. C., Aristotle on the Heavens (Loeb C.L.), p. 228.Google Scholar The clepsydra was a hollow vessel, covered at the top except for a narrow vent or tube which could be plugged with the thumb; the bottom was perforated to form a strainer. It was used for transferring liquids from one vessel to another. What Empedocles describes is the normal use of the clepsydra, except that normally it would be dipped into the liquid with the vent unplugged.
3 My analysis of the simile (lines 8–21) follows that of Regenbogen, O., ‘Eine Forschungsmethode antiker Naturwissenschaft’, Quell. u. Stud. z. Gesch. d. Mathematik, B. I, pp. 180 ff.Google Scholar
4 In line 18, taking ‘δὲ’ as apodotic and reading ‘ἐρύκει’ and in line 19 reading ‘ἠθμοῖο’, with Regenbogen.
5 Such a repetition is of course a usual feature of early Greek style; but it is hardly a necessary one.
6 ‘The region of the chest and lung, in the act of discharging the breath outwards, is filled again by the air surrounding the body, as it is driven round and makes its way inwards through the porous flesh. Again, when the air is turned back and is moving outwards through the body, it thrusts round the respiration inwards by way of the passage of mouth and nostrils.’ (Timaeus 79c, Cornford's translation.)