This set of four was originated by Yājñavalkya. It is characteristic of his philosophical teachings in the Bṛihadāraṇyaka Upaniṣad, and is not, so far as I can find, found anywhere else in early Sanskrit. Let’s look at how he used it, and how that relates to Buddhist usage. For convenience in this essay I’ll call this group the “tetrad”.
In BU 3.4, Uṣasta asks Yājñavalkya to explain the Divinity, the Self in the midst of all (ya ātmā sarvāntaras), that is directly witnessed by oneself, not by another (sākṣād aparokṣād; note that the first term here is related to the Pali sakkhi, “witness”). Yājñavalkya first replies simply by saying “this” is the Self within all. The use of pronouns to indicate the inexpressible Divinity is characteristic of Yājñavalkya’s rhetoric.
Pressed by Uṣasta for clarification, he goes on to identify the Self with he who breathes. Uṣasta is unsatisfied, responding that Yājñavalkya is merely pointing it out like one would point to a cow or a horse and thereby think one has explained what a cow or a horse is. Again, Yājñavalkya points to “this” as the self. Pressed once more, Yājñavalkya says (3.4.2):
na dṛṣṭer draṣṭāraṃ paśyeḥ | na śruteḥ śrotāraṃ śṛṇuyāḥ | na mater mantāraṃ manvīthā | na vijñāter vijñātāraṃ vijānīyāḥ | eṣa ta ātmā sarvāntaraḥ | ato ’nyad ārtam | tato hoṣastaś cākrāyaṇa upararāma
“You may not see the seer of seeing; you may not hear the hearer of hearing; you may not think the thinker of thinking; you may not cognize the cognizer of cognizing. This is your self within all. Everything else is of ill.” Then Uṣasta son of Cakra fell silent.
Here we notice some distinctive features of the discourse.
- The tetrad is introduced as the final term in the argument.
- Yājñavalkya characteristically avoids speaking directly of the final truth, requiring repeated prompting first.
- The tetrad is presented in a negative form, pointing to that which is not knowable by any of these means.
- It is speaking of a specifically spiritual reality and is not meant as a general analysis of experience.
The tetrad must be ways in which the Self was held to be found or perceivable within the Brahmanical tradition. As to what they are, exactly, we can clarify a few details.
- What is “seen” refers to things that are visible, and includes the “vision” of a holy person or a deity. Such visions are considered powerful signs within the EBTs and in the Brahmanical literature. The idea of “seeing” is, in old Indic and in modern English, employed very widely to include any kind of knowledge, not just vision. There’s an interesting example in Chāndogya Upaniṣad 3.13.8, where proof of the Divinity’s light in the person is “seen” by the evidence of the heat felt in the body. More generally, the “seen” can also refer to the “visible world”, i.e. this temporal world as opposed to the “unseen” world of the heavens.
- What is “heard” is primarily, of course, the texts handed down by tradition. Cf. Yājñavalkya’s answer to Janaka on what the light of a man is, where he says that in the darkest of nights, a sound can serve as a light, for when one’s name is called one can make one’s way even when one cannot see.
- What is “thought” is that which is philosophised or reasoned, as opposed to that which is directly experienced.
- What is “cognized” is that which is experienced in deep realisation. I believe this refers to the awareness found in deep states of absorption.
Let’s move on to the next context, this time BU 3.7. Uddālaka asks Yājñavalkya about the “inner controller”. Once again Yājñavalkya proceeds coyly, explaining a range of lesser manifestations before revealing the final answer (3.7.23).
adṛṣṭo draṣṭāśrutaḥ śrotāmato mantāvijñato vijñātā | nānyo ’to ’sti draṣṭā nānyo ’to ’sti śrotā nānyo ’to ’sti mantā nānyo ’to ’sti vijñātā | eṣa ta ātmāntaryāmy amṛtaḥ | ato ’nyad ārtam | tato hoddālaka āruṇir upararāma
“He is the unseen seer, the unheard hearer, the unthought thinker, the uncognized cognizer. There is no other seer but he, no other hearer but he, no other thinker but he, no other cognizer but he. This is your Self, the inner controller, the immortal. Everything else is of ill.” Then Uddālaka Āruṇi fell silent.
Again a few technical remarks.
- The tetrad appears in the same rhetorical situation as before, namely the final term in the argument.
- This is emphasised in the text by the questioner falling silent.
- Again the tetrad is meant to illustrate that the Divinity that is the Self cannot be known by these conventional means.
Next we turn to a dialogue with Gārgī (3.8). She asks two questions, unleashing them like a warrior his arrows. Yājñavalkya answers the first question easily. The second question concerns the fundamental principle by which all things are pervaded, “woven like warp and woof”. Yājñavalkya first says this is space, then is pressed further to identify it with the imperishable (akṣara). Because of this are heaven and earth, time, seasons, rivers, and so on.
Notably, Yājñavalkya criticizes those who perform sacrifices and other religious rites without knowing the imperishable; they are pitiable and their works temporary. But one who knows them will die a (true) brahmin. Here Yājñavalkya preempts the Buddha’s understanding of a true brahmin as due to their wisdom.
Finally he says (3.8.11):
tad vā etad akṣaraṃ gārgy adṛṣṭaṃ draṣṭraśrutaṃ śrotramataṃ mantravijñātaṃ vijñātṛ | nānyad ato ’sti draṣṭṛ | nānyad ato ’sti śrotṛ | nānyad ato ’sti mantṛ | nānyad ato ’sti vijñātṛ | etasmin nu khalv akṣare gārgy ākāśa otaś ca protaś ca
This very imperishable, Gārgī, is the unseen seer, the unheard hearer, the unthought thinker, the unknown knower. There is no other seer but this, no other hearer but this, no other thinker but this, no other cognizer but this. In this imperishable is space woven, warp and woof.
Gārgī then tells the assembled brahmins that none of them will defeat Yājñavalkya in argument, and falls silent.
- Note that the grammar is the same as the previous example, except it is now neuter instead of masculine. This shows that such differences were not definitive but illustrative. (Cf. the question of whether there is a neuter brahman in Pali.)
- Consistently the tetrad is the final term in the argument, following which the interlocutor falls silent.
Finally we come to the dialogue with Maitreyi (2.4, 4.5). This is perhaps the closest of all Upaniṣadic passages to the Suttas, one whose terms, images, and ideas are almost all echoed in the Suttas in one way or another.
Yājñavalkya tells his wife that he wishes to go forth, and will bequeath her his wealth. But she is not interested in wealth, for it does not grant immortality. He goes on to teach her the highest Divinity. First he establishes that all things in the world are only dear insofar as they reflect the Self (2.4.5):
ātmā vā are draṣṭavyaḥ śrotavyo mantavyo nididhyāsitavyo maitreyi | ātmano vā are darśanena śravaṇena matyā vijñānenedaṃ sarvaṃ viditam
It is the Self that must be seen, heard, thought, and meditated on, Maitreyi. It is by the seeing, hearing, thinking, and cognizance of the Self that all this is known.
- The two versions differ grammatically in the final phrase. 2.4.5 is in instrumental (“It is by the seeing …”) while 4.5.6 is locative (“It is when the Self is seen …”). This difference is observed in the Śatapatha text, too.
- The passage uses nididhyāsitavyo “to be meditated on” (from the same root as jhāna) synonymously with vijñāna.
Śaṅkara comments (translation by Mādhavānanda, I have modified it for consistency):
tasmādātmā vai are draṣṭavyo darśanārhaḥ, darśanaviṣayamāpādayitavyaḥ;śrotavyaḥ pūrvamācāryata āgamataśca; paścānmantavyastarkataḥ; tato nididhyāsitavyo niścayena dhyātavyaḥ; evaṃ hyasau dṛṣṭo bhavati śravaṇamanananididhyāsanasādhanairnirvartitaiḥ / yadaikatvamatānyupagatāni, tadā samyagdarśanaṃ brahmaikatvaviṣayaṃ prasidati, nānyathā śravaṇamātreṇa
Therefore ‘the Self, my dear Maitreyī, should be seen, is worthy of seeing, or should be made the object of seeing. First it should be heard of from a teacher and from the scriptures, afterwards thought about through reasoning, and then steadfastly meditated on. Thus only is it seen—when these means, viz. hearing, thought, and meditation, have been gone through. When these three are combined, then only true realisation of the unity of Brahman is accomplished, not otherwise—by hearing alone.
It seems that Śaṅkara regards the tetrad as structured around the idea of “seeing”—which Mādhavānanda translates as “realizing”—which is then made possible by the three subsequent items. This seems unlikely, since the tetrad is always presented as a flat series of four, not one thing explained by three. Thus it seems that Śaṅkara has mistaken the (by his time very archaic) meaning of “seen” here.
Radhakrishnan’s note here is interesting (p. 197).
The Śruti, the text, is the basis for intellectual development, manana. It is a means subordinate and necessary to true knowledge; nidhidhāsana is the opposite of thoughtless diffusion. It prepares for integral purity. Contemplation is not mere philosophic thought. It is a higher stage of spiritual consciousness. … The Jaina and the Buddhist systems also recognize the three stages of religious development.”
He then quotes Mātrceta referring to scripture, reflection on meaning, and meditation. This of course corresponds to suta, muta, and viññāta. Radhakrishnan does not comment on the “seen”.
Thus the Śaṅkara tradition clearly shows that the tetrad is about realizing the spiritual truth, and that the final three items refer to learning scripture, contemplating it, and meditative awareness.
Moving on, Yājñavalkya describes the Vedic texts as like the smoke arising from a damp fire. This, of course, relates to the “heard”. Then he refers to the ekāyana, the “one goal” or “convergence point” of all phenomena. This, pervading all like salt in water, is the “great being, infinite, unlimited sheer mass of consciousness.”
Maitreyī is bewildered, so Yājñavalkya further explains (2.4.14). Here he does not exactly use the tetrad, but his phrasing is still similar.
yatra hi dvaitam iva bhavati tad itara itaraṃ jighrati tad itara itaraṃ paśyati tad itara itaraṃ śṛṇoti tad itara itaraṃ jighrati tad itara itaram abhivadati tad itara itaraṃ manute tad itara itaraṃ vijānāti | yatra vāsya sarvam ātmaivābhūt tat kena kaṃ jighret tat kena kaṃ jighret tat kena kaṃ paśyet tat kena kaṃ śṛṇuyāt tat kena kam abhivadet tat kena kaṃ manvīta tat kena kaṃ vijānīyāt | yenedaṃ sarvaṃ vijānāti taṃ kena vijānīyāt | vijñātāram are kena vijānīyād iti
For where there seems to be duality, there one smells another, sees another, hears another, speaks to another, thinks of another, cognizes another. Where all has become just the Self, then by what and whom would one smell, see, hear, speak, think, or cognize? By what would one cognize that by which all this is cognized? By what, my dear, would one cognize the cognizer?
- The text in 4.5.15 includes other senses (taste and touch) as well as the action of speaking.
This passage adds complexity to the treatment of the tetrad. In the first three passages, the tetrad was introduced specifically to indicate that the ultimate Divinity was not knowable by the conventional means of spiritual awareness. Here, however, Yājñavalkya says that the Self should be known by these means.
This parallels exactly the situation in Buddhism, for the Buddha typically employed the tetrad to indicate Nibbana as beyond sense experience, yet in some places he said that one was also not able to get enlightened without these things. There is no paradox here. Both teachers are simply indicating that the conventional means of spiritual learning are not, in and of themselves, a realization of the Ultimate. But they are part of the educational development that leads to realization of the Ultimate.
These passages show that Yājñavalkya used the tetrad as a way of summarising the means of spiritual learning. This has been well understood by the commentator, with the exception of the “seen”, around which there is a lack of clarity. Perhaps this is not unexpected, given the very wide scope of “seeing” in Indic thought.
From the context of the suttas, I believe that “seeing” refers to the sight of a holy person. This is what is known in later devotional Hinduism as darshan. Here are a few examples from the Suttas.
- Snp 2.4:10.2: One of the highest blessings is the “sight of ascetics”.
- DN 14:2.14.1: When Vipassī saw a renunciate it spurred his going forth. This later became the template for Gotama’s story.
- AN 6.30:2.5: “The unsurpassable seeing is when someone with settled faith and love, sure and devoted, goes to see a Realized One or their disciple. This is in order to purify sentient beings, to get past sorrow and crying, to make an end of pain and sadness, to discover the system, and to realize extinguishment.”
- People frequently express their wish to “go and see” the Buddha (eg. AN 8.12:2.6, DN 16:5.24.7).
- MN 81:6.5: Such seeing is “deemed as holy”.
- AN 1.338:1.1: Few are those who get to see the Buddha, many are those who do not.
- AN 3.22:8.1: “Some people can enter the sure path with regards to skilful qualities, but only if they get to see a Realized One, and to hear the teaching and training that he proclaims, and not when they don’t get those things.”
- AN 6.56:9.3: The sight of the Buddha or his disciple at death, and hearing the teaching, can help some to let go of fetters. Remember that in an oral culture, it was only when in the sight of a sage that one could hear the teaching.
- DN 20:4.2: Deities gather from all world systems to see the Buddha and the Sangha.
It is not, however, that “seeing” in and of itself results in purity. The Suddhaṭṭhakasutta (Snp 4.4) addresses the idea that the seeing of a pure, perfect one would grant purity. The Buddha criticizes this, pointing out that a pure person cannot purify the impure.
The brahmin speaks not of purity from another in terms of what has been seen, heard, or thought; or by precepts or vows.
One who is still attached visits various teachers, but one who knows does not need to visit many teachers, and are remote from all things “seen, heard, or thought”. If someone were to see that wise person, they would not judge them.
This sutta is especially relevant, as it refers to the seen, heard, and thought, and thus is clearly in the scope of the tetrad. In line with most texts of this chapter, the Aṭṭhakavagga, it omits reference to the “cognized”, as this chapter addresses those ascetics who were debaters and controversialists, rather than those who were meditators.
I don’t believe we can find a similar idea in the limited corpus of Yājñavalkya. However, in Chāndogya Upaniṣad 7.8.1, “vigor” (or “health”) is praised, for one who is healthy is up and about and may then serve his teacher.
sa yadā balī bhavatyathotthātā bhavatyuttiṣṭhanparicaritā bhavati paricarannupasattā bhavatyupasīdandraṣṭā bhavati śrotā bhavati mantā bhavati boddhā bhavati kartā bhavati vijñātā bhavati.
When a man has vigor, he rises; rising, he serves; serving, he approaches nearer; approaching nearer, he sees, hears, reflects (mantā), understands (boddhā), acts, and cognizes.
Here we have a sequence that places “seeing” as part of the process towards understanding religious truths, and includes “hearing”, “thinking”, and “cognizing”. This is similar to the presentation in the Suttas, and there is no reason to think this was not a widely understood standard view.
Thus in both early Buddhism and Brahmanism, the tetrad “seen, heard, thought, and cognized” was a summary of the ways that conventional religious truths were realized. The Buddha adopted this framework from Yājñavalkya, presumably learning it under his former teachers.
The perspectives of the Buddha and Yājñavalkya had much in common. They both acknowledged the tetrad, and spoke of how they helped one to realize the truth. At the same time, they also spoke of the limitations of the tetrad, agreeing that the final realization could not be described in these terms.
Where they differed was in how the ultimate was presented in relation to the tetrad.
For Yājñavalkya, the tetrad revealed that the ultimate Divinity that is the Self could not be perceived by these conventional means, for it was the knowing, not the known; “the unseen seer, the unheard hearer, the unthought thinker, the uncognized cognizer”.
The Buddha rejected any such notion of an unconditioned consciousness. For him, all consciousness was conditioned and hence impermanent. Thus rather than directing meditators to realize the infinite consciousness behind the scenes, he taught that one should see that, “in the seen will be merely the seen; in the heard will be merely the heard; in the thought will be merely the thought; in the known will be merely the known” (SN 35.95, Ud 1.10).
In a way, this is another point of agreement between the Buddha and Yājñavalkya. Both asserted that the true Self could not be seen by means of the tetrad. For Yājñavalkya, that meant there was a more subtle reality, an unknown but infinite divine consciousness. For the Buddha, it meant that what is known should be left as what is known, without metaphysical assumptions. AN 4.24:
Such a one does not take anything
seen, heard, or thought to be ultimately true or false.
But others get attached, thinking it’s the truth,
limited by their preconceptions.
It seems that the meaning and context of this tetrad was lost fairly early in the Theravada tradition. We have seen that the Hindu commentator Śaṅkara seems to have misunderstood the implication of “seen” here, taking it in the wider sense of “realized”. The Theravada texts make a different mistake, construing muta (what has been “thought”) to mean what was smelt, tasted, and touched. This is obviously incorrect, as muta is from a standard root that always means “thought” or similar. That these two erudite traditions made different mistakes should alert us that the exact meaning is not made obvious or explicit, and must be carefully inferred from context.
The original understanding, however, seems to be maintained in Asaṅga’s Abhidharmasamuccaya. It treats the tetrad as an explanation of “perception” (saññā), where “perception” does not mean “sense perception” per se, but rather the cognitive recognition and interpretation that underlies concept formation. Perception in this sense is frequently used with the tetrad in the Suttas, for example in Snp 4.4:5.2, one who visits different teachers is said to be “attached to perception” (saññasatto). Asaṅga says:
Perception is the apprehending of the counterpart of diverse phenomena by which the meaning of what has been seen, heard, thought, or cognized is conveyed.
Thus the tetrad is bound up not with sense experience in general, but in the apprehension and communication of ideas, the ‘counterparts” (pratibimba) of sense experience. This relation is emphasised often in the sutta, eg. at AN 4.183, which discusses when it is appropriate to talk about what has been known via the tetrad.
Obviously the tetrad relates to sense experience, since we learn spiritual truths through our eyes and ears. What we think about and what we realize in meditation ultimately depend on such experience, too. Thus it is quite possible to make a critical argument regarding the tetrad. Something like: “Since the sight of a holy person is ultimately just a visual experience; and the hearing of a teaching is just an auditory experience, then both of these things reduce to sense perception, and are impermanent and unreliable like any other sense perception.”
But this is not to say that the tetrad is nothing more than an abbreviated way of talking about sense experience. It is used by both the Buddha and Yājñavalkya to describe the means by which spiritual truths are known, and to point to the mysterious truth that ultimately none of them are adequate. Along with countless other examples, this shows how the Buddha was familiar with details of Yājñavalkya’s teaching in particular, and responded to it meaningfully and critically.
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