Book 10
1.52
Again, hearing takes place when a current passes from the object, whether person or thing, which emits voice or sound or noise, or produces the sensation of hearing in any way whatever. This current is broken up into homogeneous particles, which at the same time preserve a certain mutual connexion and a distinctive unity extending to the object which emitted them, and thus, for the most part, cause the perception in that case or, if not, merely indicate the presence of the external object.
1.53
For without the transmission from the object of a certain interconnexion of the parts no such sensation could arise. Therefore we must not suppose that the air itself is moulded into shape by the voice emitted or something similarAir is not, as Democritus held (Beare, op. cit.p. 99), the medium, any more than for vision (§ 49). By something similar Epicurus probably means to include sound or noise. Lucretius treats of hearing in iv. 524-614, ii. 410-413.; for it is very far from being the case that the air is acted upon by it in this way. The blow which is struck in us when we utter a sound causes such a displacement of the particles as serves to produce a current resembling breath, and this displacement gives rise to the sensation of hearing.
