Verse 33: How does cognition give rise to the notion of time?

antaḥ karaṇaṃ trividhaṃ daśadhā bāhyaṃ trayasya viṣayākhyam |
sāmpratakālaṃ bāhyaṃ trikālam ābhyantaraṃ karaṇam ||

antar – internal
tri – three
dasa – ten
bāhya – external

sāmprata – now / present
kāla – time
bāhya – external
trikālam – three times
ābhyantara – internal

The ten external organs-of-sense function only in the present, the three internal organs function at all three times.

1. The thirteen organs involved in cognition are divided into two groups: the three internal organs and the ten external organs.
2. The three are considered internal organs because they operate within the body and are applied to objects that are also inside the body.
3. The three internal organs perceive the ten external organs (see verse 26). The ten external organs are therefore the objects of the three internal organs.
4. The three internal organs function through the ten external organs.
5. The ten are considered external because they are applied to objects outside the body.
6. The ten external organs always operate in the present: the eye sees forms that are present, the nose smells scents that are present, the hand grasps objects that are present.
7. Unlike the external organs, the internal organs can operate in all three times: past, present and future:
   1. Past: I recognize that it rained because the river is full of water.
   2. Present: I recognize that there is fire on the mountain because there is smoke on the mountain.
   3. Future: I recognize that it may rain because the ants are moving their eggs.
8. Inference (see verse 5) makes it possible for the three internal organs to experience past and future.
9. Yet the operation of the three internal organs is always anchored in past or present operation of the ten external organs.
10. The notion of time itself arises from this relationship between the three internal and ten external organs.