I think this is a good question. I’m not sure if this will be helpful but from my amateur research it looks like indriya is the older term of the two. If you’re familiar with the Vedic pantheon you’ll see a relation to the god Indra, who is the most commonly cited god in the Vedas (Indra 289, Agni 218, Soma 123, etc.) In the older Vedas such as the Ṛg, Indriya apparently has the sense of power, force, or quality belonging to Indra. In the much later Atharva Veda it starts to have the sense of faculty or organ of sense.
Āyatana is not used in the Vedas as far as I can tell, but is used in the Chāndogya Upaniṣad. The Upaniṣads occur after the last Veda and the earliest of those may or may not be contemporary with the Buddha. The meaning of āyatana here is something like sanctuary, resting-place, abode or a support. To me, this is a broader meaning than the faculty/organ sense of indriya (obviously the meaning relating to Indra is probably not being invoked in the suttas). I think this broader meaning is also evident in your reference to the arūpa samāpatti, where there are no longer perceptions pertaining to form.
Regarding the five spiritual faculties, my interpretation is that they are more of a poetic/metaphorical “sense”. I’ve not heard any teachers talk about this that I can recall at least, but I think there might be a relation between the ordinary lower 5 senses and the 5 spiritual faculties. In other words, as sense-restraint (indriyasaṃvara) combined with other spiritual trainings are developed, the developing person comes to use these spiritual faculties (pañcindriyāni) as an undeveloped person uses their ordinary 5 lower senses.
That’s very interesting to open up to the brahmanic perspective! a while ago I looked up the veda references in the suttas in a discussion. And it’s rather save to say that the first three vedas were known in the Buddha’s time, whereas the fourth veda appeared shortly after as a clear reference, a Snp verse and more clearly in the Milindapanha. Maybe there are articles about indriya in the vedas-upanishads somewhere?
Yea, I think it provides perspective to see the historical context where the suttas play out. As far as I know, the only other texts we can look to for this kind of perspective are the Vedas (for the pretext) and early Upaniṣads (for the context). Many words would be used in the same way, and some may differ in quite interesting ways as some scholars have pointed out.
I tried some searching but couldn’t find any good research on these terms usage in the Brahmanical traditions.
I did find this quote in an essay by Swami Śivānanda:
“Ayatana means mind (Chandogya Upanishad, IV-vii) which is the substratum of the experiences of all other organs. Senses cannot do anything, if the mind is not connected with them. When you are wholly absorbed in the study of an interesting newspaper, you do not hear when your friend loudly calls you.”
Another way to investigate this question might be the grammatical method. Indriya and āyatana can be either nouns or adjectives, is indriya usually used as an adjective and āyatana as a noun? The more noun-like one I would think is the more foundational.
We might again be misled by translation. In the PTS dictionary we find for Āyatana:
3a) ajjhatt˚: 1. cakkhu eye, 2. sota ear
it seems though that cakkhu is not the physical eye but ‘seeing’ (I also remember Bh. Sujato writing something like this somewhere)
For a reference here a quote from Olivelle’s Introduction to “The Early Upanishads”
In dealing with sight and hearing … [the early upanishads] clearly distinguish the power or the act of seeing and hearing from the respective external organs, the eyes and the ears. Indeed, they consistently use different Sanskrit terms for the two—cakṣus and śrotra for sight and hearing, and akṣan and karṇa for eye and ear, respectively.
So cakṣus / cakkhu is ‘seeing’ then and not ‘the eye’.
The same applies to indriya. The PTS dictionary has
cakkh-undriya - “the eye which is a power”
when it should translate “the power of seeing” / “the seeing-power”
This is not trivial as it spills over to the question of how much of the core dhamma deals with physical entities / organs - or rather experiences / mental phenomena.
The Saḷ’āyatana-Saṃyutta (Sixfold-Sphere division of the Saṃyutta Nikāya) variously lists a number of factors that belong in each of the six spheres. For instance in the eye sphere we have:
(11) … eye, form, eye consciousness, eye contact and whatever arises with eye contact as a condition. (SN 35.24-28)
The eye, ear, nose, etc. are faculties (indriya) that allow the events that constitute seeing, hearing, smelling and so on to occur.
To restate; within the broader eye sense sphere (āyatana) there is not only the eye sense faculty (indriya) but also the eye sense-objects (visual-forms/rūpa), eye-consciousness, contact, feeling, craving.
So it would seem āyatana is the broader of the two terms.
Further, in the infamous “all”/sabba suttas occuring in the saḷ’āyatana saṃyutta it is said:
If anyone, bhikkhus, should speak thus, ‘Having rejected this all, I shall make known another all’, that would be a mere empty boast on his part. … that would not be within his domain.”
Which seems to be talking about the exhaustive breadth of the experiential world. I don’t think indriya is ever used in such an extensive sense.
Hi Matt, I am currently revisiting ayatana in an extended way - not finished yet - but for now I would agree with your conclusion. I haven’t done any work on indriya yet, but I would now understand ayatana as a ‘dimension’ or ‘realm’ that allows a very specific set of experiences.
Just to give examples of how ayatana is used
we have the 6-(sense-)ayatana (which I take as one dimension - our normal dimension of experience)
the closely related phassāyatana
the four separate arupa-ayatana (ākāsānañcāyatana, viññāṇañcāyatana, ākiñcaññāyatana, nevasaññānāsaññāyatana)
we sometimes have vimuttāyatana
in AN 9.69 even ariyāyatana
and some less clear terms: abhibhāyatana, kasiṇāyatana, satiāyatana, arannāyatana
Āyatana: Seat, location, support. The home & foothold of indriya.
Indriya: Faculty, force, power (as in cognitive or perceptual power).
The eye is the seat of the faculty of seeing. Cakku is the āyatana of the indriya of seeing.
The eye not as physical, but as potentially sensual. Viz. a potential faculty - that (sensually) actualizes itself with the descent of the indriya .
Restraint of the spheres of senses (ajjhatikāni āyatanani,) implies that the sensual faculties of the āyatanani are not triggered by the descent (avakkanti) of the indriyani.
As for seeing, it means that we would see - but not with our own sensuality.
Simple, isn’t it?
Now what’s a bit trickier (in Buddhism,) is why & how, there is a descent (avakkanti) of the indriya in the āyatana. For instance, like here in SN 22.47
Maybe there shouldn’t be much of a mix-up between the bāhirani (external) āyatanāni and the ajjhatikāni (internal) spheres (supports).
Form - bāhira (external) āyatana- is an āyatana.
Eye - ajjhatikā (internal) āyatāna - is an āyatana.
Definitely, these two are supports for some form of sensorial undergoing. The internal with their indriyāni. The form (external) with the sensuality it conveys (like what you feel from seeing a Picasso vs. what you could feel with the same frame and kind of paint material, from another lousy picture).
What kind of indriya could you put into form, as an external āyatana? Picasso’s indriya?
As far as sense-consciousness is concerned, it does “support” the sensuous experience alright, (might it be restrained [no indriya on your part - yet still that Picasso feeling that hits your consciousness]; or unrestrained [you get both Picasso’s feeling + you put your own sensory undergoing + your sense consciousness that follows the lead of Picasso’s feeling + your own feeling on top of it, as you appropriate it].
As “support”, āyatana does not have the meaning of ārammaṇa; that is to say an expedient - namely anything to be depended upon as a means of achieving what is desired - But as the inactive support of a phenomena (physical & mental); on which an active faculty (power) will graft itself. They are fabrications (saṅkhāra) SN 36.11.
I would say that ārammaṇa is a support born of satta’s intention; while āyatana is more cosmic. That does not preclude a cosmic intention though - A cosmic expedient - A cosmic desire. Does it?
However, I suppose you should not include contact, feeling, craving in the āyatanāni.
Isn’t saḷāyatana a nidāna of itself? And aren’t contact feeling and craving, nidānas of themselves?. Are these latter fabrications, or mere experiences?