Is Advaita's Nirguna Brahman same as Madhyamaka's "emptiness of emptiness"?

Question

In Adi Shankaracharya's Advaita Vedanta, Nirguna Brahman (Brahman without form or qualities) is the Para Brahman (Supreme Brahman) according to this Wikipedia article. This is the Ultimate Reality of Advaita.

Meanwhile in Buddhist philosopher Nagarjuna's Madhyamaka, the Ultimate Reality is described as the "emptiness of emptiness" (from this Wikipedia article):

Central to Madhyamaka philosophy is śūnyatā, "emptiness." The term refers to the "emptiness" of inherent existence: all phenomena are empty of "substance" or "essence" (Sanskrit: svabhāva) or inherent existence, because they are dependently co-arisen. At a conventional level, "things" do exist, but ultimately they are "empty" of inherent existence. But this "emptiness" itself is also "empty": it does not have an existence on its own, nor does it refer to a transcendental reality beyond or above phenomenal reality.

Also:

Nagarjuna's critique of the notion of own-nature (svabhāva) argues that anything which arises according to conditions, as all phenomena do, can have no inherent nature, for what is depends on what conditions it. Moreover, if there is nothing with own-nature, there can be nothing with 'other-nature' (para-bhāva), i.e. something which is dependent for its existence and nature on something else which has own-nature. Furthermore, if there is neither own-nature nor other-nature, there cannot be anything with a true, substantial existent nature (bhāva). If there is no true existent, then there can be no non-existent (abhāva).

If Advaita's Nirguna Brahman does not have any form or qualities whatsoever, then is it the same as Madhyamaka's "emptiness of emptiness"?

If not, then what is the difference?

Answer 1

If sunyata is absolutism, then it can be argued that Sankara’s Nirguna Brahman is identical to sunyata. Numerous Buddologists, both past and contemporary would agree. David Loy states that the Mahayana sunyata corresponds to the Vedantic Brahman. (Loy, David 1997. Non-Duality: A Study in Comparative Philosophy, p. 211) Natalia Isayeva says: “On the whole European scholars were inclined to accept the idea of a positive character of sunya, representing a kind of general background of the world, so that emptiness meant for them something rather like ineffability, impossibility of being grasped by verbal means. (Isayeva, Natalia 1993. Shankara and Indian Philosophy, p. 188). Examining the spectrum of opinions on this matter, T. Stecherbatsky wrote: ‘And if Prof. Keith and Prof. M. Walleser suppose that Nagarjuna stops at negation or denies even the empirical reality of the world, it is only because his real aim, the positive counterpart of his negativism...had escaped their attention.’” (Stecherbatsky, T. 1956. The Central Conception of Buddhism, p. 52. as quoted in Isayeva, p. 188).

In chapter twenty-five, Examination of Nirvana, Nagarjuna states (Jay Garfield translator, The Fundamental Wisdom of the Middle Way: Narguna’s Mulamadhyamakakarika):

    7.    If nirvana were not existent,
        How could it be appropriate for it to be nonexistent?
        Where nirvana is not existent,
        It cannot be nonexistent.
     14.    How could nirvana
        Be both existent and nonexistent?
        These two cannot be in the same place.
        Like light and darkness.
     15.    Nirvana is said to be 
        Neither existent nor nonexistent.
        If the existent and the nonexistent were established,
        This would be established.
     16.    If nirvana is
        Neither existent nor nonexistent,
        Then by whom is it expounded
        “Neither existent nor nonexistent”?
     17.    Having passed into nirvana, the Victorious Conqueror
        Is neither said to be existent
        Nor said to be nonexistent.
        Neither both nor neither are said.

Commenting on this verse, Garfield states “This emphasizes that all discourse is only possible from the conventional point of view. When we try to say something coherent about the nature of things from an ultimate standpoint, we end up talking nonsense. But recall the discussion of emptiness and convention in chapter XXIV: We can develop an understanding of emptiness in relation to conventional reality, of emptiness as empty: Emptiness seen that way simply is the lack of essence of the conventional. Its own emptiness is the fact that it itself is no more that that.” (pp 330-1). Garfield in his final footnote to his translation states “Wood (1994) argues, following his nihilistic interpretation of Nagarjuna, that here.... Nagarjuna is, in virtue of denying the existence of even his own view, completing a nihilistic program that denies the existence of any kind to anything. As should be clear by now, I think that this nihilistic reading is untenable. Nonetheless, it is surely the case that Wood is correct in claiming that Nagarjuna wishes to treat emptiness in exactly the same way that he treats other phenomena ---as empty--- and that any theory about it presupposes it has an essence must be false. I part company with Wood only when he goes on to interpret emptiness as complete nonexistence..Nagarjuna is working to show the merely conventional character of his utterance and that its utility does not entail the existence of any convention-independent reality as its semantic value. But this is a far cry from nihilism. See Garfield (unpublished) for a more sustained discussion of emptiness and positionlessness.” (p 358).

The semantics here are key. “Emptiness” does not mean nihilism. It connotates the negation of perceived reality - of reality as fullness of the senses. It does not connotate empty space, it does not connotate nothingness. It connotates the lack, the negation, of “fullness”. Fullness may be said to be that which we all experience. Our individual consciousness’ receive a constant bombardment of sensual information from our senses with information on the outside perceived reality of the senses. When we experience what we think of as perceived reality through the senses there is a certain ‘fullness’ to it all -- our consciousness is constantly full because of constant stimuli from the senses. Emptiness is not a positive statement as to the nature of sunya, it is meant solely as a negative statement of perceived reality - the lack of fullness, the lack of sensual stimuli, the lack of perception; the lack of perceiver and perceived. However to imply devoidness or nihilism is equally unfair. I think the proper interpretation of Nagarjuna is that he was, and meant to be, silent on the matter.

But why silent? I think it is important to pause and consider a third alternative - sunyata as neither absolutism nor negativism. Nagarjuna, like the Buddha, neither posited absolutism or negativism. He was silent - thus the controversy. In his book Western Approaches to Eastern Philosophy, Troy Wilson Organ spends an entire chapter on the Buddha’s silence regarding the nature of Nirvana. Organ says on pp 181-2 quoting T.W. Rhys Davids translation of Dialogues of the Buddha, Sacred Books of the Buddhists:

Thus, there came to be known as the avyakrtavastuni -- the undetermined, or
unelucidated, or unprofitable questions. The most comprehensive list of forbidden speculations is found in the Brahma Jala Sutta of the Digha Nikaya. Here are listed sixty-two ways in which “recluses and Brahmans...reconstruct the past and arrange the future.” The Buddha says they “are entrapped in the net of these sixty-two modes; this way and that they plunge about, but they are in it; this way and that they flounder, but they are included in it, caught in it.” Buddhists are warned to avoid the net altogether.

Organ then goes on to list 6 possible reasons for the Buddha’s silence (and I would argue Nagarjuna). These include 1) Buddha agreed with the then prevailing beliefs, 2) Buddha disagreed with the then prevailing beliefs, 3) Buddha held no beliefs, 4) Buddha simply wouldn’t say what his beliefs were 5) Buddha found language wanting to express his knowledge, and 6) Buddha would not be diverted from his mission (pp 184-95). In light of the last reason I think a seventh and better answer is Buddha did not want his students diverted from their mission. What your belief was -or is- is not important to the problem at hand, or its solution. He and Nagarjuna did not want them spending their time engaged in “unprofitable questions”. There is a story often quoted that the Buddha once responded with the following answer (my paraphrasing)- If you find yourself caught in a burning building, what do you do? Do you stop and speculate how the building came to be, when it was built, who built it, and what it is made of? Do you then speculate as to how the fire came to be and what it’s nature is and what the nature of fires are to buildings? Or do you try to get out of the building? If someone on the outside is shouting “save yourself, jump out the window!” Do you stop and ask them why you should jump, or ask them to explain to you what the nature of the outside is before you jump? Buddha believed that we are all in bodies with death the inescapable outcome. This was purpose enough for us to heed his shouts to jump to Nirvana. Nagarjuna, being a Buddhist, gave argumentation through the Mulamadhyamakakarika for people to jump. He, like the Buddha, stopped short on the nature of Nirvana simply because it diverted from the main message - to escape death, and the endless rounds of birth and death. Nagarjuna felt that the nature of sunyata was an “unprofitable question”. There was no need to give answer as to the nature of the “outside”- there was reason enough to escape the burning house.

I think Nagarjuna would agree that scholars who argue over whether nihilism or absolutism is implied were simply engaging in “unprofitable questions” as “recluses and Brahmans...reconstruct[ing] the past and arrange[ing] the future.” The best interpretation of Nagarjuna is that he did not imply anything as to the nature of sunyata, both interpretations are equally valid (or invalid). It is noteworthy to point out the very last verse and especially the last line of the entire Mulamadhyamakakarika (Jay Garfield translator):

  30. I prostrate to Gautama
        Who through compassion
        Taught the true doctrine,
        Which leads to the relinquishing of all views.

Mudgal (Mudgal, S. G., Advaita of Sankara - A Reappraisal: Impact of Buddhism and Samkhya on Sankara’s Thought, p.158) says Nagarjuna’s view is not “No reality” but, rather, “no view of Reality”. Mudgal states that Nagarjuna, in Ratnavali I.57, denounces nihilism as leading to hell (p 156). [In addition to a very good argument equating Buddhism and the Advaita Vedanta, Mudgal also has an extensive argument on absolutism in Nagarjuna.] Matilal agrees with this interpretation of Nagarjuna. He equates Nagarjuna’s non-assertions as simply non-assertions and not assertions of the opposite and states “I read this assertation [a verse of Nagarjuna’s] as a claim that the statement about the truth of ‘emptiness’, that any thesis about reality is empty, is itself not an asserted statement...my suggestion is that it is as good as an unstated statement,...The emptiness of all metaphysical theses can be shown, not stated in language.” (Matilal, Bimal Krishna, The Word and The World: India’s Contribution to the Study of Language, p. 154) Loy would agree with Matilal. He states that because any of these statements (either assertive or non-assertive) is dependent upon its opposite statement, neither is absolute, and “any philosophical positioning affirming only one [statement] can be shown to be meaningless.” (p 203).

But returning to our original question - how can we reconcile emptiness to Shankara’s absolutism that others, previously quoted, said was implied in Nagarjuna? Because the experience of the One, of emptiness, is to experience “...no thing / nothing. To be aware that there is only One actually implies that there are two; the One, and that which is aware of the One as being One...What makes this [Sankara’s Advaita] equivalent to Mahayana is that a self which can never be objectively experienced, because by definition it is the experiencer, can just as well be described as sunya. However, then this will be not a nihilistic emptiness (which was Sankara’s mistaken criticism of Madhyamika) but a sunyata that can be cherished as the Buddha-nature essence of all things.” (Mudgal, p. 179). Indeed, according to Mudgal, the two, Sunya and Brahman, have the same meaning and can be interchanged. (p 179). Prof. Chandradhar Sharma also deals with this question extensively in pp 318-34 (Chapter 17: Buddhism and Vedanta) of his book A Critical Survey of India Philosophy (available here - https://archive.org/details/IndianPhilosophyACriticalSurvey). Before giving his comments on sunyata and Brahman, I’d like to give his general comments at the beginning of this section. On p 318 he says:

Buddhism and Vedanta should not be viewed as two opposed systems but only as different stages in the development of of the same central thought which starts with the Upanishads, finds its indirect support in Buddha, its elaboration in Mahayana Buddhism, its open revival in Gaudapada, which realizes its zenith in Shankara and culminates in the Post-Shankaraites.

So far as the similarities between Buddhism and Vedanta are concerned, they are so many and so strong that by no stretch of the imagination can they be denied or explained otherwise, So far as the differences are concerned, they are few and mostly not vital. Most of them rest on a grave misunderstanding of Buddhism.

And on p 319:

Ashvaghosa realized that after Buddha’s Nirvana, Buddha’s teachings were perverted by the Hinayanists who reduced mind to fleeting ideas and matter to fleeting sensations, who placed Buddha in place of God and who denied the ultimate existence of mind and matter. Ashvaghosa challenged the Hinyanists and refuted their views. He knew well that Buddha’s real philosophy was based on the Upanishads and he tried to revive it, The Tathata of Ashvaghosa also called as Bhuta-tathata, Tathagatagarbha, Dharmakaya, Dharmadhatu, Alayavijnana, Bodhi or Prajna is in fact the same as the Atman or Brahman of the Upanishads. Relativity (pratityasmutpada) is the realm of the intellect which is a product of Avidya, The Absolute is untouched by it. ‘It is wrong to take the work of Ignorance as ultimate and to forget the foundation on which it stands,’ says Ashvaghosa (Outlines of Mahayana Buddhism, D.T. Suzuki, p 124). The Tathata of Ashvaghosa which is Bodhi or Vijnana or Pure Consciousness together with its two aspects—the Absolute ‘Suchness’ and the conditional ‘suchness’ reminds us of the Atman or the Brahman of the Upanishads with its two aspects—the higher and the lower nirguna ot the para and the saguna or the apara. The Tathata and the Brahman, both are jnanaghana or Pure Consciousness and the anirvachaniya or indescribable in the sense that intellect fails to grasp them fully. The ‘Ignorance’ of Ashvaghosa is the avidya of the Upanishads. The phenomenal and the absolute standpoints of Ashvaghosa are the vyavaharika and the paramarthika standpoints of the Upansihads. Asvaghosa uses those very similes commonly used in the Upanishads—the similes of waves and water, or pots and clay, or ornaments and gold etc. It is unmistakably clear that the Upanishads exercised a great influence on Ashvaghosa. Indeed, avoiding all the contradictions of Hinayana, Ashvaghosa has rightly interpreted Buddha in the light of the Upanishads and has placed Buddhism on a firm basis.

And on pp 321-22:

The only difference between Shunyavada and Vedanta, therefore, is the difference of emphasis only. This difference is of a double nature. Firstly, while Shunyavada is more keen to emphasize the ultimate unreality of the all phenomena, Shankara and his followers are more keen to emphasize the empirical reality of all phenomena; and secondly while Shunyavada is less keen to develop the conception of Ultimate Reality, Vedanta is more keen to develop this conception almost to perfection. And this is not unnatural if we remember that Shunyavada represents the earlier stage while Vedanta represents the latter stage of development of the same thought.

What then of the Vedantic doctrines of the Saguna and Nirguna Brahmans? Does this not lend contradictions to an equation of Brahman and Sunya? I don’t believe it does. The Hindu saint Ramakrishna once stated that the difference between the Nirguna Brahman and the Saguna Brahman was the same as the difference between a snake at rest and a snake in motion - both are one and the same snake (Gospel of Sri Ramakrishna). Another way to view this is a borrowing from the Western tradition. Western positive theology is what can be said of God, God with attributes [Saguna Brahman]. Western negative theology is what cannot be said of God, God without attributes [Nirguna Brahman]. It is not a question of which way is better or which way is God; both are simply methodologies for understanding- but not knowing. Finally, my own discussions with practicing Buddhist Tibetan monks and Advaitan Indian monks. Both have said there is no difference between the Advaita Vedanta and Buddhism. Based on the various scholars and comments in the above I would argue that there are more sound arguments equating the Buddhist Sunya and the Vedantic Brahman and less justifiable arguments equating Sunya with nihilism.

And pp 324-5:

It is generally said that Nairatmyavada or the No-Soul theory and Ksana-bhanga-vada or the theory of momentariness are the two main and vital theories which distinguish Buddhism from Vedanta. Let us now briefly summarize our views in regard to these two theories.

We maintain that by Nairatmyavada Buddhism does not deny the existence of the true Atman, the Pure Self which is Pure Consciousness and which is the only reality. Buddhism takes the word ‘Atman’ in the sense of of the individual ego-complex or the Jivatman which is a product of beginningless Avidya, Maya or Vasana and which is associated with the Antahkarana or the Buddhi. Thus Buddha and the Mahayanists have found it easy to repudiate this Atman (Jiva), while at the same time accepting its empirical reality. It is in fact the ‘self of straw’ which they have erected simply to demolish it afterwards. The real self is untouched by their criticism. They have, in one sense or the other, either implicitly or explicitly, always accepted its reality. It is called, not generally Atman, but Bodhi, Prajna, Chitta, Bodhi-chitta, Tattva, Vijnana, Chittamatra, Vijnanamatra, Vijnaptimatra, Tathata, Tathagatagarbha, Dharmadhatu, Dharma-kaya or Buddhakaya. Ashvaghosa calls it Atman also (Saundarananda, XIV, 52). Assanga calls it Shuddhatman, Mahatman and Paramatman (Mahayanasutralankara, XIV, 37; IX, 23). Even Shantara ksita calls it Vishuddhatman (Tattvasangraha, 3535).

Thus it is a great irony of fate that the Buddhists and the Vedantists fought against each other. Nairatmyavada has been horribly misunderstood both by the Buddhists and by the Vedantins. And Buddha and the Buddhists themselves were greatly responsible for creating this misunderstanding. The Upanishads have repeatedly used the word Atman as a synonym of Reality. Buddha admitted this Reality. Buddha admitted this Reality and termed it Bodhi or Prajna. But instead of frankly identifying his Bodhi with the Atman, Buddha degraded Atman to the level of the Jiva and easily condemned it as unreal...

And pp326-7:

But it is important to remember that the Pure Self which is Pure Consciousness is always admitted by Buddhism to be the ultimate Reality. Buddha himself identified Reality with Bodhi or Prajna. The Tathata of Ashvaghosa is Alayavijnana or Absolute Consciousness. The Mahayana-sutras indentify Reality with Consciousness and call it Prapancha-Shunya, Atarkya, Sarvavagvisayatita, Advaya, Achintya, Anaksara, Anabhilapya, Atyanata-vishuddha and Pratyatmavedya. It is significant to note that though the Reality is generally not called Atman, it is sometimes described as Brahman. Thus we find in the Astasahasrika (Tattva-Sangraha, p 476) that all things are such that they neither come in or nor go out, they are neither pure nor impure, they are free from attachment and detachment, they are undefiled, unattached and uncontaminated because they are of the very nature of Brahman. The same Sutra tells that for supreme enlightenment one dwells in Brahman (p 34). The Shastasaharika (p 1460) and the Lalitavistara (p 3) describe Reality as Full of Bliss in the beginning, in the middle, and in the end. One, Full, Pure and the Abode of Brahman. The Saddharmapundarika (p 118) says that one who truly follows the teaching of the Buddha ever dwells in the Brahman, the Absolute, the Pure, the Calm, the Blissful and the Undefiled…Asanga also says that by becoming one with Pure Spirit, one realizes the last, the fourth meditation, and then one ever dwells in the blissful Brahman.

Thus we see that Buddhism generally means by Atman what Vedanta means by Jivatman or Buddhi or Chitta or Antahkarana. And on the other hand, Buddhism generally means by Chitta or Vijnana or Vijnaapti or Bodhi or Prajna what Vedanta means by Atman or Brahman or Samvit or Chit. Thus the Vedantic Atman generally becomes the Buddhistic Chitta, and the Vedantic Chitta generally becomes the Buddhistic Atman. Had Buddha refrained from committing an error of commission in degrading the Upanishadic Atman to the level of the empirical ego and also an error of omission in not identifying his Bodhi or Prajna with the Upanishadic Atman, the age-old battle regarding the Nairatmyavada fought without any reasonable ground by the Buddhists and the Vedantists on the soil of Indian Philosophy would have surely been avoided.

Most Vedantists learn their views of Mahayana Buddhism and most Mahayana Buddhists learn their views of Vedanta and Buddhism from the teachers of their own traditions and never study or learn the other tradition or compare the philosophical traditions in detail. Shankara equated Nirvana and Sunyata with the nihilism of the Theravedic (Hinayana) school, even though Gaudapada recognized the differences in the two major Buddhistic schools. Many of the Mahayana equated the atman with the empirical ego, propagating their incomplete view of the Advaita. Thus, the incomplete views and misinterpretations of each others views continues to this day.

Answer 2

First: What did Adi Shankaracharya teach?

We can see this from Adi Shankaracharya's own compositions:

ब्रह्म सत्यं जगन्मिथ्या जीवो ब्रह्मैव नापरः
brahma satyam jaganmithyA jIvo brahmaiva nAparah
Brahman is real, the universe is an illusion. The jiva is Brahman itself and not different. (Brahmajnanavalimala 20)

This Atman is a self-cognised entity because It is cognised by Itself. Hence the individual soul is itself and directly the Supreme Brahman, and nothing else. (Vivekachudamani 216)

There exists no other material cause of this phenomenal universe except Brahman. Hence this whole universe is but Brahman and nothing else. (Aparokshanubhuti 45)

The pot, wall, etc., are all nothing but clay. Likewise, the entire universe is nothing but Brahman. (Brahmajnanavalimala 19)

Brahman is Existence, Knowledge, Infinity, pure, supreme, self-existent, eternal and indivisible Bliss, not different (in reality) from the individual soul, and devoid of interior or exterior. It is (ever) triumphant. It is this Supreme Oneness which alone is real, since there is nothing else but the Self. Verily, there remains no other independent entity in the state of realisation of the highest Truth. All this universe which through ignorance appears as of diverse forms, is nothing else but Brahman which is absolutely free from all the limitations of human thought. A jar, though a modification of clay, is not different from it; everywhere the jar is essentially the same as the clay. Why then call it a jar ? It is fictitious, a fancied name merely. None can demonstrate that the essence of a jar is something other than the clay (of which it is made). Hence the jar is merely imagined (as separate) through delusion, and the component clay alone is the abiding reality in respect of it. Similarly, the whole universe, being the effect of the real Brahman, is in reality nothing but Brahman. Its essence is That, and it does not exist apart from It. He who says it does is still under delusion - he babbles like one asleep. This universe is verily Brahman - such is the august pronouncement of the Atharva Veda. Therefore this universe is nothing but Brahman, for that which is superimposed (on something) has no separate existence from its substratum. (Vivekachudamani 225-231)

Therefore the universe does not exist apart from the Supreme Self; and the perception of its separateness is false like the qualities (of blueness etc., in the sky). Has a superimposed attribute any meaning apart from its substratum? It is the substratum which appears like that through delusion. (Vivekachudamani 235)

Becoming thyself the self-effulgent Brahman, the substratum of all phenomena - as that Reality give up both the macrocosm and the microcosm, like two filthy receptacles. (Vivekachudamani 289)

The above quotes clearly show the teaching of eternalism.

Brahman is eternal, infinite, self-existent and transcendental absolute reality. Brahman is the substratum or foundation of the universe. Brahman is the material cause of the universe. Brahman is the only thing that is permanent and ultimately real, while the universe is ultimately an illusion.

The individual soul, which is a self-cognized entity, is ultimately the same as Brahman.

While Brahman is without qualities, it appears as the universe and individuals with qualities, through delusion.

This summarizes the nature of reality according to Advaita Vedanta.

Second: What did the Buddha teach?

We can see this in the Buddha's own words (Buddhavacana), from the Sutta Pitaka in Pali, which is included in the Mahayana Agamas and the Tibetan Kangyur.

It is widely speculated that some Buddhist schools teach annihilationism or nihilism, but this is not true. It is only non-Buddhists who have this wrong impression. The Buddha and 99.9% of Buddhist schools teach the middle way between eternalism and annihilationism. This "middle way" teaching is the unique feature of the Buddha's teachings.

The Buddha rubbished the notion that there is no self of any kind:

“So, brahmin, when there is the element of endeavoring, endeavoring beings are clearly discerned; of such beings, this is the self-doer, this, the other-doer. I have not, brahmin, seen or heard such a doctrine, such a view as yours. How, indeed, could one — moving forward by himself, moving back by himself — say ‘There is no self-doer, there is no other-doer’?” - Attakari Sutta

However, the Buddha was very clear in the Ananda Sutta (SN44.10) that rejecting both eternalism and annihilationism, he teaches that "all phenomena is not self", which means that there is no permanent or eternal standalone entity of a self in all phenomena (sabbe dhamma anatta).

"Ananda, if I — being asked by Vacchagotta the wanderer if there is a self — were to answer that there is a self, that would be conforming with those brahmins & contemplatives who are exponents of eternalism [the view that there is an eternal, unchanging soul]. If I — being asked by Vacchagotta the wanderer if there is no self — were to answer that there is no self, that would be conforming with those brahmins & contemplatives who are exponents of annihilationism [the view that death is the annihilation of consciousness]. If I — being asked by Vacchagotta the wanderer if there is a self — were to answer that there is a self, would that be in keeping with the arising of knowledge that all phenomena are not-self?"

"No, lord."

"And if I — being asked by Vacchagotta the wanderer if there is no self — were to answer that there is no self, the bewildered Vacchagotta would become even more bewildered: 'Does the self I used to have now not exist?'"

The Buddha instead taught that the self is not eternal and not non-existent, but is dependently originated (Pratītyasamutpāda):

When the Buddha was asked by the naked ascetic Kassapa whether suffering was of one's own making or of another's or both or neither, the Buddha replied "Do not put it like that." When asked whether there was no suffering or whether the Buddha neither knew nor saw it, the Buddha replied that there was, and that he both knew and saw it. He then said "Kassapa, if one asserts that 'He who makes (it) feels (it): being one existent from the beginning, his suffering is of his own making,' then one arrives at eternalism. But if one asserts that one makes (it), another feels (it); being one existent crushed out by feeling, his suffering is of another's making,' then one arrives at annihilationism. Instead of resorting to either extreme a Tathaagata teaches the Dhamma by the middle way (by dependent origination)" - summarized here from Acela Sutta

A summary of dependent origination is that the self arises dependent on the inter-working of the five aggregates of form, feeling, perception, mental fabrications, and consciousness.

He taught that both the views of "I have a self" and "I have no self" are inaccurate in the Sabbasava Sutta. He also taught that the views of one being Nirvana, one being in Nirvana, one being apart from Nirvana, calling Nirvana "mine", and delighting in Nirvana, are inaccurate in the Mulapariyaya Sutta.

The Buddha did teach emptiness, but it is restricted to the nature of the self i.e. all phenomena is empty of a self (see Shunya Sutta). The Buddha did not comment on the nature of all non-sentient things like the universe, besides noting them as being conditioned and impermanent.

The Buddha was not interested in commenting on the nature or origin of the universe, because he considered it to be unimportant to the path to liberation from suffering - see the Parable of the Poisoned Arrow (from MN63). The Buddha was not interested in metaphysical speculations. It was not because he taught the Upanishadic truths through silence, as implied by Prof. Chandradhar Sharma.

Third: What did Nagarjuna teach?

While the Buddha stopped at describing the "middle way" and emptiness with respect to the nature of the self, Nagarjuna expanded these concepts to cover the nature of the universe and all reality. He did this in his magnum opus, the Mūlamadhyamakakārikā, whose name itself means "Fundamental Verses on the Middle Way". Nagarjuna did not contradict the Buddha's teachings, but rather, expanded it.

The Wikipedia article on Madhyamaka (which contains its own citations) summarized Nagarjuna's teachings very well:

Central to Madhyamaka philosophy is śūnyatā, "emptiness." The term refers to the "emptiness" of inherent existence: all phenomena are empty of "substance" or "essence" (Sanskrit: svabhāva) or inherent existence, because they are dependently co-arisen. At a conventional level, "things" do exist, but ultimately they are "empty" of inherent existence. But this "emptiness" itself is also "empty": it does not have an existence on its own, nor does it refer to a transcendental reality beyond or above phenomenal reality.

Nagarjuna's critique of the notion of own-nature (svabhāva) argues that anything which arises according to conditions, as all phenomena do, can have no inherent nature, for what is depends on what conditions it. Moreover, if there is nothing with own-nature, there can be nothing with 'other-nature' (para-bhāva), i.e. something which is dependent for its existence and nature on something else which has own-nature. Furthermore, if there is neither own-nature nor other-nature, there cannot be anything with a true, substantial existent nature (bhāva). If there is no true existent, then there can be no non-existent (abhāva).

Rather than the annihilationism that nothing exists or the eternalism that something exists eternally, Nagarjuna taught the "middle way" that all phenomena is empty of its own "inherent existence" or "substance" or "essence" (what he called svabhāva).

If nothing has inherent substance, then nothing can depend on something else for substance, so there is no other inherent substance (para-bhāva).

Nagarjuna's unique philosophy however, is that even this emptiness is empty i.e. this emptiness does not have its own inherent substance. This means that there is no transcendental reality beyond phenomenal reality. This is what is implied by ultimate reality not being absolute reality.

A very nice and simplified explanation of the Madhyamaka emptiness can be found in Zen master Thich Nhat Hanh's writing, "The Fullness of Emptiness".

The only disagreement between Theravada and Madhyamaka is the need to expand the "middle way" and "emptiness" beyond what the Buddha taught. What is common between Theravada and Madhyamaka is that both reject eternalism and annihilationism.

Fourth: Comparing Advaita and Madhyamaka

Comparing what Adi Shankaracharya taught and what Nagarjuna taught, we come to see very clearly that both are not the same and in fact, completely incompatible:

• Shankara said Brahman is eternal and absolute. Meanwhile, Nagarjuna said nothing is eternal and absolute.
• Shankara's Brahman (clay analogy) implies that it is the only thing that has a true inherent substance (what Nagarjuna called svabhāva). Meanwhile, Nagarjuna says nothing has inherent substance.
• Shankara's Brahman is the material cause (again, clay analogy) of the universe. Meanwhile, Nagarjuna's emptiness is not a material cause for anything including itself.
• Shankara said that the universe depends on Brahman as its substratum (what Nagarjuna called para-bhāva). Meanwhile, Nagarjuna said there is no other inherent substance (para-bhāva) i.e. no substratum for anything else.
• Shankara's Brahman is the Ultimate Reality that is the Transcendental Absolute Reality. Meanwhile, Nagarjuna's Ultimate Reality is an "emptiness of emptiness" that is devoid of transcendental or absolute reality.

What is common between Advaita and Madhyamaka is that both proclaim the non-dualism between the Ultimate Reality and the phenomenal reality. However, Advaita's Ultimate Reality is a Transcendental Absolute Reality, while Madhyamaka's Ultimate Reality is the "emptiness of emptiness" that is devoid of any transcendental or absolute reality.

My conclusion is that Adi Shankaracharya's Nirguna Brahman and Madhyamaka's "emptiness of emptiness" are not the same and in fact, completely incompatible.

This is supported by Banaras Hindu University Professor T. R. V. Murti's statement (quoted below) in this book chapter: Murti T.R.V. (1973) Saṁvṛti and Paramārtha in Mādhyamika and Advaita Vedānta. In: Sprung M. (eds) The Problem of Two Truths in Buddhism and Vedānta. Springer, Dordrecht

It has been the fashion to consider that the differences between the Madhyamika śūnyatā and Brahman are rather superficial and even verbal, and that the two systems of philosophy are almost identical. At least Professor Radhakrishnan thinks so, and Stcherbatsky's and Dasgupta's views are not very different. I hold a contrary view altogether: that in spite of superficial similarities in form and terminology, the differences between them are deep and pervasive.

Fifth: Comparing Vedanta and Buddhism

All Vedanta schools accept that Atman is eternal (according to Bhagavad Gita 2.20), and Brahman is absolute and eternal. This is based on the wisdom of the Upanishads.

Meanwhile, the anatman teaching subscribed by all schools of Buddhism, states that there is no eternal self (i.e. no permanent standalone eternal entity) in all phenomena.

A very apt conclusion for this comes from eminent German indologist Professor Helmuth von Glasenapp's essay "Vedanta and Buddhism: A Comparative Study":

Nothing shows better the great distance that separates the Vedanta and the teachings of the Buddha, than the fact that the two principal concepts of Upanishadic wisdom, Atman and Brahman, do not appear anywhere in the Buddhist texts, with the clear and distinct meaning of a "primordial ground of the world, core of existence, ens realissimum (true substance)," or similarly.