Indian Philosophy v2.c24.s6.4

v2.c24.s6.4

Ākāśa, which pervades all space and not air, is the substratum of sound.¹ Sound can be produced even in a vacuum, though we cannot hear it, since there is no air to convey it. The quality of sound does not depend on air though the loudness, etc., do.² It is, however, produced by the contact of two hard substances. One sound produces another which causes another, until the last sound ceases owing to some obstacle.³ We cannot argue that sound is eternal simply because it has an intangible substratum.⁴