Exactly :=)
Just imagine a vast, infinite ocean (with no waves, ripples or bubbles).
Or imagine an infinite void or empty space (with no sun, moon, stars, galaxies, planets asteroids, or forms, but only emptiness)
In both these examples, there exists none other than the infinite ocean-water,
or none other than the infinite empty-space. Due to this reason, there is no sense of duality or multiplicity.
There is no distinction (you-me, subject-object, this-that etc.).
In this unmanifested state there exists only One infinite spirit, Brahman.
That's what Advaita says.
We the common folks see differences, due to our ignorance and identification with shapes and forms. But these very shapes and forms have their origin in the ultimate substance Brahman, just like icebergs, waves, bubbles are made up of water and nothing else.