'faculties', is a name for 22, partly physical, partly mental, phenomena often treated in the Suttas as well as in the Abhidhamma. They are:
6 Bases (āyatana):
- 1. eye: cakkhu
- 2. ear: sota
- 3. nose: ghāna
- 4. tongue: jivhā
- 5. body: kāya
- 6. mind: mano
5 Feelings (vedanā)
- 7. femininity: itthi
- 8. masculinity: purisa
- 9. vitality: jīvita
5 Spiritual Faculties (s. bala)
- 10. bodily pleasant feeling: sukha
- 11. bodily pain: dukkha
- 12. gladness: somanassa
- 13. sadness: domanassa
- 14. indifference: upekkhā
3 Supermundane Faculties
- 15. faith: saddhā
- 16. energy: viriya
- 17. mindfulness: sati
- 18. concentration: samādhi
- 19. wisdom: paññā
- 20. the assurance: 'I shall know what I did not yet know!': aññātañ-ñassāmīt' indriya
- 21. the faculty of highest knowledge: aññindriya
- 22. the faculty of him who knows: aññātāvindriya.
(1-5, 7-8) are physical; (9) is either physical or mental. All the rest are mental.
(14) (s. upekkhā) is here merely indifferent feeling (= adukkha-m-asukhā vedanā, i.e. 'neither pleasant nor unpleasant feeling') and not identical with that highly ethical state of equanimity (= tatramajjhattatā, i.e. 'keeping everywhere the middle', the equipoise of mind), also called upekkhā which belongs to the group of mental formations (sankhāra-kkhandha; s. Tab II).
(20) arises at the moment of entering the Sotāpatti-Path (sotāpatti-magga), (21) on reaching the Sotāpatti-Fruition (sotāpatti-phala), (22) at attaining the Arahat-Fruition (arahatta-phala). For the three last, s. ariya-puggala.
The faculties, excepting (7) and (8), form one of the 24 conditions (paccaya 16).
In Vibh. V all these faculties are treated in the above order, whereas S.XLVIII enumerates and explains them by way of the above indicated groups, leaving only 20-22 unexplained. See Vis XVI; Path 138ff.
For the 5 spiritual faculties (15-19), s. The Way of Wisdom (WHEEL 65/66).