Vivart vad contrasts with Atitvad. Both are forms of Vedanta, although Atit vad has been much less well known.
Vivart vad, Ajat Vad, and Adwaita are basically, generally the same. This view asserts that the only ultimate reality is formless and that form (including change of those forms such as birth) does not actually exist, it only appears to exist, and this appearance is false, not true, not really or ultimately present or actual (by 'form' is meant the objects of all five senses, not just sight).
Atit vad, in contrast, asks, 'How much sense does it make to say that since the wave is all water, the wave does not exist'? In other words, that the fact that the content of of all forms is abstract and formless Being or Godhead, does not invalidate the structure of the form. Content does not invalidate structure, according to Atit. The fact that all form is made of Brahm, does not invalidate the forms of Brahm (including the ultimate Form of Brahm, the supreme Personality of Godhead) --Godhead having both supremely personal, and supremely impersonal aspects (Ishwara and Brahman).
Atit goes further than this, and says that not only does the Brahman-only content of form not invalidate the form (all forms, the jagat or world), it legitimatizes form and the world: Both boundaries and boundary-making, instead of being due to illusion or maya as vivart vad holds, are due to the activity of Brahm (Godhead, Spirit).
An important related difference between vivart and atit is that vivart sees ultimate reality (Brahman) as basically or generally silent or inactive (although 'silent' applies only to hearing, it is used in spiritual circles to mean 'inactive' but in a living or positive sort of sense). Advaita (vivart vad) sees activity as mysteriously arising out of silence. In other words, advaita cannot explain the presence of either activity, or form. It just refers to form and activity as the 'nature' of Brahman, but somehow not true or real.
Atit Vad in contrast sees ultimate reality as a blend of both silence and dynamism. Activity (Prakriti, especially Paraprakriti) are not in second place to silence. Neither Purusha nor Prakriti are seen as dominant or subordinate or more holistic than the other. In fact, for atit vad, silence and dynamism are not things, but aspects, views, darshans of one reality (Brahm).
The practical result of both these views are dramatically and importantly different:
Vivart vad, in denying the reality of form, activity, and world creates an otherworldly, unrealistic, lethargic, passive personality over time. It is also associated with male chauvanism in using the Sankhya terms Purusha and Prakriti for Brahman and maya, and since Purusha has a male ending, and Prakriti a female ending, this leads to the unspoken assumption and orientation that male is more important, fundamental, and more holistic value (since Purusha is taken as more important, more all-inclusive, than Prakriti - the so-called 'Hindu Adam's rib.
Atit vad Vedanta is not world-rejecting or denying. It embraces and values BOTH form and formless. In this way, it is fundamentally different not only from advaita vedanta, but also from various theistic/dualistic traditions which assert the validity of form and and the world, and God, but lessen the importance and ontological status of all-pervading Unity/Brahman, and sometimes even the existence of a single all-pervading reality.
There is also an important difference between Vivart Vedanta and Atit Vedanta. regarding God (Ishwara, Bhagwan). Advaita/vivart implicitly denies God as ultimate. "Duality we imagine for the sake of devotion" is attributed to Shankara, or a supposed early or younger Shankara. Obviously, duality, a kind of duality, is required for God's existence, or God could not be an object of experience. For God to be meaningful, there must be the dualism of the individual and God.
Vivart denies this duality, and thereby God is placed, at least implicitly, in the same category as jiva and jagat - illusory, imaginary. Because all duality for advaita/vivart is illusory, imaginary. Followers of advaita are left with an inexplicable contradiction between an ultimate impersonal inactive Brahman that places devotion and their Object of devotion as non-ultimate.
This is not the case for Atit Vedanta, which affirms both unity and duality, the One and the Many, formless and form, Brahman and Ishwara.
Atit Vad is not pantheism. It does not say that Brahman is nothing other than the relative and its activity, or that there is nothing transcendental to jagrat (waking state) perception and experience. According to Atit, it is not that silence is transcendental to relative activity. Instead, there are levels of refinement of Brahm - saguna and nirguna Brahm. But nirguna does not mean silent unity only. It means that the activity of nirguna Brahm is more refined, unmanifest, latent, not expressed.
Vivart vad can be seen as stating something similar in saying the maya or form is the 'nature' latent in Brahm. But the difference is that adwaita says this nature is illusory, unreal, whereas Atit vad says that the word 'nature' means identity and essence, and that causation of the world is due to the manifestation of the real latent potentiality of Brahm, which is a blend of real silence and real activity (two aspects, not two 'things').
Regarding Shankara and what he said and did not say, Vedantic scholarship c. 2020 is showing evidence that many works attributed to Shankara may not have been written by him. Richard Jones, for example, states that the Brahma Sutra Bhashya is the only work that has scholarly consensus as having been written by Adishankara, although other texts may have been authored by him. Sue Hamilton in her Oxford Very Short Introduction to Indian Philosophy makes similar statements, and even states that Shankara did not use the term 'maya.' Statements by these or other modern scholars (such as Paul Hacker?) assert that Shankara's views of vivart vad may have been misportrayed, and are not consistently in line with the typical advaitic views of the world being entirely illusory. Richard King is an example of another contemporary scholar who is differentiating between traditional legends and attributions of Shankara, and the widely forgotten influence of his disciples and rivals of the time and later (Cf. King's Indian Philosophy)
an example of Shankara sometimes leaning toward atit rather than vivart:
The view attributed to Shankara of the world as Saguna Brahman (qualified Brahman or Brahman with qualities) implies that the forms of the world are in fact Brahman and therefore ultimate, not false. So there is a contrasting or contradiction inherent in Vivart vad (or at least Shankara's version of it) of accepting and denying the Brahman (ultimate) nature of the world.
Sri Aurobindo calls the view that the world and form are not ultimately real "the Great Denial," and states it is due to the experience of a very advanced - but not final - stage or level of higher states of consciousness. The experience of silent Unity of the Self-as-all is at first so overwhelmingly powerful, and overshadow the experience of Ishwara's divinity, that it can seem to be final. But eventually integration proceeds and one begins to see the blend of both silence and activity, impersonal and personal, in the full nature of Brahm, Spirit, Godhead.
Bottom Line: Adherents and devotees of spirituality have seemed to have an either-or choice of two views: either Unity or duality - either spiritual life or material life, either the One or the Many:
- ultimate Unity with no duality is real (One, not Many)
- ultimate duality with no Unity is real (God/duality, not One)
A variation on this is to diminish Unity or duality compared to the other, also creating profound imbalance deep within the personality (prajnaaparaadh).
Atit Vad removes the need for this dissatisfying and metaphysically and subconsciously frustrating choice by accepting the ultimacy of both Unity and Duality, formless and form, Brahman and Ishwara, impersonal and personal, intellect and heart, making rejection of either metaphysical reality or physical reality unnecessary. This lays the foundation for a philosophy that embraces life, while avoiding excessive attachment, and eventually freeing one from spiritual bondage without lifestyle or attitudinal renunciation.