Yoga Sutra 4.13 they consist of the gunas
Sūtra IV.13
They are manifest or subtle, and consist of the guṇa-s
These three time-phases are present when of manifest nature. Past and future are essentially subtle, being the six Unparticularized. All this is, from the highest point of view, simply to be distinguished as a conglomerate of the guṇa-s, and so it says in the holy classic:
The ultimate form of the guṇa-s is not within the range of perception;
What can be perceived of it is but slight, like māyā.
They are manifest or subtle, and consist of the guṇa-s. These three time-phases coming up in the three forms of past, future and present, are present coming up in the present mode when of manifest nature. Their essence is, that they have become objects of public awareness. Past and future are essentially subtle and not objects of public awareness, being of the nature of the six Unparticularized (II. 19), their essence being I-am-ness and the other five. From these they take on (further) manifestation as the sixteen vikāra-changes (elements and organs) characterized by effect and cause.
All this, of the form of effect and cause (body and senses) in relation to the individual self, and essentially manifest, and also what is subtle in the form of the Unparticularized like I-am-ness and the others, and further what is the liṅga-mātra (= the Great principle, II.19) which is the subtle beyond the Unparticularized, all this world of sattva, rajas and tamas, ever tending towards light, activity and stasis respectively, is from the highest point of view simply to be distinguished as a conglomerate of the guṇa-s, as essentially guṇa-s, as consisting of the guṇa-s of sattva, rajas and tamas, which are ever tending towards light, activity and stasis, and so it says in the holy classic:
The ultimate form of the guṇa-s is not within the range of perception;
What can be perceived of it is but slight, like māyā.
Their ultimate form is freely arising in each separate thing, and in itself is not within the range of perception, not in the field of the senses; what can be seen of it is the conglomeration of disparate things disturbed by the clashing of the guṇa-s, like māyā but not just māyā. Like māyā, however, in its uncertainty. Slight: as being an insignificant and purely local change in the guṇa-s equally existing everywhere.
(Opponent) When everything is guṇa-s, how is it that a sound, for instance, is a single thing, with a single sense-organ (to perceive it)?
(Opponent) When everything earth and all others is guṇa-s, how is it that a sound like that from a conch is a single thing, with a single sense-organ such as the ear, so that there is a single focal point for the mind? It ought not to be so: what is a product of triplicity should produce an idea which is triple. And in the same way, there should be triplicity of each of the sense-organs. In which case, there would be no selectivity, because selection (in the case of hearing, for example) presupposes a single sound as perceived object and a single ear as perceiver. The same thing would apply to the object and sense-organ of touch and the other senses. Yet we do find selectivity.
(Answer) The reason is now to be given: