Emp. Fr. v. 307 — τό τ’ ἐν μήνιγξιν ἐεργμένον ὠγύγιον πῦρ — πῦρ δ’ ἔξω διαθρῶσκον, &c.
Empedokles illustrates this influx and efflux of air in respiration by the klepsydra, a vessel with one high and narrow neck, but with a broad bottom pierced with many small holes. When the neck was kept closed by the finger or otherwise, the vessel might be plunged into water, but no water would ascend into it through the holes in the bottom, because of the resistance of the air within. As soon as the neck was freed from pressure, and the air within allowed to escape, the water would immediately rush up through the holes in the bottom.
This illustration is interesting. It shows that Empedokles was distinctly aware of the pressure of the air as countervailing the ascending movement of the water, and the removal of that pressure as allowing such movement. Vers. 286:—
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οὐδέ τ’ ἐς ἄγγος δ’ ὄμβρος ἐσέρχεται,
ἀλλά μιν εἴργει ἀέρος ὄγκος ἔσωθε πεσὼν ἐπὶ τρήματα πυκνά, &c. |
This dealing with the klepsydra seems to have been a favourite amusement with children.
Doctrine of effluvia and pores — explanation of perceptions — Intercommunication of the elements with the sentient subject — like acting upon like.
The doctrine of pores and effluvia, which formed so conspicuous an item in the physics of Empedokles, was applied by him to explain sensation. He maintained the general doctrine (which Parmenides had advanced before him, and which Plato retained after him), that sensation was produced by like acting upon like: Herakleitus before him, and Anaxagoras after him, held that it was produced by unlike acting upon unlike. Empedokles tried (what Parmenides had not tried) to apply his doctrine to the various senses separately.[128] Man was composed of the same four elements as the universe around him: and since like always tended towards like, so by each of the four elements within himself, he perceived and knew the like element without. Effluvia from all bodies entered his pores, wherever they found a suitable channel: hence he perceived and knew earth by earth, water by water, and so forth.[129] Empedokles, assuming perception and knowledge to be produced by such intercommunication of the four elements, believed that not man and animals only, but plants and other substances besides, perceived and knew in the same way. Everything possessed a certain measure of knowledge, though less in degree, than man, who was a more compound structure.[130] Perception and knowledge was more developed in different animals in proportion as their elementary composition was more mixed and varied. The blood, as the most compound portion of the whole body, was the principal seat of intelligence.[131]
[128] Theophrastus, De Sensu, s. 2, p. 647, Schneid.
[129] Emp. Frag. Karst. v. 267, seq.
| γνῶθ’, ὅτι πάντων εἰσὶν ἀποῤῥοαὶ ὅσσ’ ἐγένοντο, &c. |