Alongside Purusha Sukta (10.90), the Nasadiya Sukta (10.129) is one of the most famous Suktas of the Vedas. Known as the Creation Hymn, its fourth mantra says,

In the beginning, there was the disturbance of desire, from which sprung the first seed, which was born of the mind. Sages, searching in their hearts, realised the wisdom of the connection between existence and non-existence.

The creation the Nasadiya Sukta discusses is often believed to be the origin of the universe. However, 10.129.4 does not refer to any ordinary creation but, rather, the illusion of duality. This is attributed to desire in the mind – the first ‘seed’ of ignorance which gives the impression that we are separate. Before this disturbance, there was nothing to realise and no one to know because there was no appearance which was taken to be real as separate from the Self or Brahman.

Gaudapada similarly declares in their Mandukya Karika:

2.32. There’s really no one who’s bound, no one seeking liberation, and no one who becomes liberated. This is the highest truth.

Being bound, seeking or becoming liberated implies that there is someone (subject) that these things (object) happen to. It is by taking duality to be real that there is bondage, a seeker and liberation. When the illusion of separation is seen through, there is only the highest, undifferentiated truth of Brahman.

Ignorance refers to there being something ‘other’ than Brahman or taking its forms to be different from it. The Nasadiya Sukta, itself, describes the state of mind before this disturbance as there, “being nothing other than that” (10.129.2). In Brihadaranyaka Upanishad [1], we find the same idea,

1.2.1. In the beginning there was nothing here: this was covered by death, by hunger, for hunger is death. Death made the mind by desiring, ‘If only I could have a Self!’

It is the thought of having a Self which plants the seed that we are separate and imagine there to be something else. Shankara explains that there is no real creation and that it is only discussed for the purpose of understanding the truth of Advaita [2]. With duality not being real, creation cannot be said to be, as it would mean what was created existed separately from the Self.

The ‘beginning’ that the Nasadiya Sukta and Brihadaranyaka Upanishad refer to is before the appearance of duality is taken to be real. The Brihadaranyaka Upanishad  (1.4.10) later repeats this idea in its mahavakya, ‘Aham Brahmasmi’ – “I am Brahman” –

In the beginning, Brahman was this. It knew only itself: ‘I am Brahman.’ Through that it became all. [3]

When desire or hunger is present, there is the illusion of Brahman knowing something other than itself.

Finally, “the wisdom of the connection between existence and non-existence” which the Nasadiya Sukta mentions refers to the Real and Unreal. The Real is the eternal, non-dual Self, whilst the Unreal are the separate selves, world and forms. For one who has realised the wisdom of this connection, duality is a falsehood. For one who confuses the Real and Unreal, the desire in the mind is perceived to be real and belonging to a self which is desiring.

In this way, the existence and non-existence that is spoken about is the disturbance of desire. The wise who have realised the connection know the cause of the disturbance and the solution for it. The knowledge of Advaita is knowing there never was a disturbance, whereas, caught up in illusion, we confuse the activity of the mind (Unreal) with the unchanging (Real) Self. Our ability to perceive the desire as real depends on whether we think duality is. If there is no separation, there is no one desiring and it cannot be said there ever was any desire. It is believing that there was which is the disturbance.

[1] Roebuck’s translation
[2] Shankara Mandukya Karika Bhashya 3.24:

if creation were real, then the existence of the variety of objects would be absolutely real. Consequently there ought not to be Scriptural texts implying their unreality. But there are such Scriptural texts as, “In this (Ātman) there is no multiplicity,” etc., which negate the existence of duality. Therefore creation (imaginary) has been imagined in order to help the understanding of the non-duality of Ātman.

[3] Roebuck’s translation