must persist and cannot cease to exist. Some people allow a particular sound and a particular motion to persist, and some of these also allow a particular sound to be beginningless.

There is no difference between motion and sound. As for spoken letters, people hold two different views: do they constitute the limits of sound, or can letters arranged in sequence exist without sound?

When it is said that a spoken letter cannot exist except with sound, the term “letter” may denote the ending and interruption of sound, or it may denote the segmented sound itself. Likewise, the word “letter” is used for a written letter: sometimes it means merely the shape, abstracted from its material, and sometimes it means the combination of material and shape—that is, ink formed into a shape.

The second question concerns different sounds, whether they are held necessarily to follow one another in succession or a particular sound is held capable of persisting: can they subsist in a single sound-producing subject, provided that the locus of one sound is not identical to the locus of another, even though the sound-producing subject is one?

There is no doubt that there is even stronger reason to allow this than to allow different motions to subsist in a single moving subject, when each motion subsists in a locus different from that of the other.

As for two sounds or two motions coexisting in a single locus, this is impossible because they are mutually incompatible, according to most rational thinkers, or because the locus lacks sufficient capacity, according to some of them—as with the coexistence of two instances of knowledge