Ninetieth technique. Direct philosophical contemplation. Ātmano nirvikārasya — for the Self that is immutable, without modifications. The ātman does not change. It has never changed. All that changes is not it.

Kva jñānaṃ kva ca vā kriyā — where is knowledge? Where is action? Devastating rhetorical questions. If the Self is immutable, it cannot know (because knowing implies change of state) nor act (because acting implies movement). Knowledge and action belong to the phenomenal level.

Jñānāyattā bahirbhāvāḥ — external states depend on knowledge. All we perceive as external world is a construction of knowledge. Ataḥ śūnyam idaṃ jagat — therefore, this world is void. Not nonexistent. Void of independent existence. The world is real as experience, void as substance. This contemplation, sustained with firmness, dissolves the apparent solidity of everything.