Ajātivāda is the most radical position of Advaita, set out by Gauḍapāda in his commentary on the Māṇḍūkya Upaniṣad. Since the real cannot become something else and the unreal cannot come to be, nothing has ever been born; the world of change is like a dream. Śaṅkara accepted the view as the highest truth.
Ajātivāda
The doctrine of non-origination: Gauḍapāda’s teaching that nothing has ever truly come into being.
Also: Ajativada