The question is very excellent because it exposes the inauthentic understanding of Advaita that vast sections of Hindus suffer from.
Advaita does not say that everything is unreal. In fact, nowhere in Adi Shankara's works do we find the oft-quoted phrase "brahma satyaṃ jaganmithyā". What we can glean from Adi Shankara's Brahmasutrabhashya is that Advaita defines reality at three levels of perception or experience:
- prātibhāsika (apparent or illusive)
- vyāvahārika (empirical or phenomenal)
- pāramārthika (transcendental or ideal or noumenal)
None of these levels is absolutely real or unreal by itself. They are all more real or less real from the perspective of one another. These three levels do not intersect or negate each other. At each level, that level is the absolute reality. The relativity of levels is only recognizable from a different level than the one being observed.
Here’s an episode from the life of Adi Shankara, the greatest teacher of Advaita:
Once during his travels across India, teaching and debating, Adi Shankara had a discussion with a king. The king misunderstood Advaita and thought that Shankara was teaching that the world is unreal, and nothing has any value. To mock Shankara, the king ordered his attendants to release the wildest elephant in his stable just as Shankara was walking down the path of the royal garden. As soon as he saw the elephant charging, Shankara broke into a sprint and quickly climbed up the tallest coconut tree nearby.
Seeing this apparently hilarious spectacle, the king laughed and asked Shankara, why he ran from the imaginary elephant, as according to Advaita, everything is unreal? To this, Shankara gave a witty reply that what the king saw as Shankara running was also equally as imaginary as the charging elephant.
This witty episode really explains the true philosophy of Advaita.
Adi Shankara was not a fool to ignore the real-world threat of the charging elephant at the physical mundane level of existence. He protected himself with all his physical capabilities. At a higher level of consciousness, the physical level is less real, but these two levels do not interact. This was the misunderstanding of the king, who mixed the two levels of consciousness and mocked Advaita.
But today, Hindus are getting confused from the opposite side — in their immense faith, they apply their naive and dangerously wrong understanding of Advaita to the real, physical, mundane world.
Even after enlightenment, the world exists. If this fact is not part of the enlightenment, then that is not real enlightenment, but only an illusion of enlightenment :-) Do you get the irony?
Even after enlightenment, you feel hunger, thirst and all the physical conditions. Enlightenment means that you live and work in the world with the knowledge that this is not ultimate, this is not the be-all and end-all of existence. But this plane of existence does not interact with the plane of Saccidananda.
If Adi Shankara did not see the significance of debating and defeating real-world flesh-and-blood people, and re-establishing Hindu Vedic religion in a physical sense, he would not have taken the pains of travelling through the length and breadth of India and establishing real physical maṭhas and temples and rituals. He would have just sat in his home in Kerala, thinking, “Everything is the same, so there is no difference whether I go and preach Advaita or whether Hinduism dies.”
Please read this very detailed explanation of these levels of existence: