Sage Sankara said: ~ The world is unreal and Brahman alone is real. It means that birth, life, and death, which happen within the world, also is unreal.+

Sage Sankara said: ~ The world is unreal and Brahman alone is real. It means that birth, life, and death, which happen within the world, also is unreal. If birth, life, and death are unreal, then the rebirth reincarnation, and the Avataric concept must be unreal. Thus, it is for the seeker to find out, from what standpoint the world becomes unreal, to know the Brahman, which is the ultimate truth.

Causality taught in the Upanishads is only to enable us to understand the supreme truth of no-origination. The world is not different from the ‘Self’ and the ‘Self’ is not different from Atman and Atman is not different from Brahman. That the non-dual absolute appears as a diverse world is only an illusion. If it really became diverse, then the immortal would become mortal.

The dualists who seek to prove the origination of the unborn, by that very enterprise try to make the immortal, mortal. Ultimate nature can never change - the immortal can never become mortal and vice versa.

Sage Goudpada quotes from the Upanishads:~ "There's no plurality here"; "The Soul through its powers appears to be many"; "those who are attached to the creation or production or origination go to utter darkness"; "the unborn is never reborn, for what can produce it?

Remember:~

The whole world which one perceives is illusionary; it is just an appearance of unreality and there is only one indeterminate and attributeless truth at the root of this world".

The Soul, the 'Self' has none of those attributes or tags. Hence, the person who superimposes all those attributes on the changeless, eternal Soul, the ‘Self’, and identifies the Soul, the ‘Self’ with the body is confusing one for the other; and is, therefore, an ignorant person.

Sage Sankara affirming his belief in one eternal unchanging reality (Brahman) and the illusion of plurality, drives home the point that Upanishads deal not with rituals but with the knowledge of the Absolute (Brahma Vidya) and the Upanishads give us an insight into the essential nature of the Soul, the Self which is identical with the Absolute, the Brahman. 

Sage Sankara: ~ Atman, the Self is verily Brahman (God in truth), being equanimous, quiescent, and by nature absolute Existence, Knowledge, and Bliss. Atman is not the body which is non-existence itself. 

All the attributes and qualities belong to the dualistic illusion. The Soul is qualityless and attributeless because it is a formless, timeless, and spaceless existence.

Only dualist sages who take the illusory world as a reality propagated the attributes and qualities to the Soul, which is qualityless and attributeless purity. : ~Santthosh Kumaar