The final state of observation approaches

The final state of observation approaches the actual substance of mind where you observe that both existence and non-existence are not real, and yet both existence and non-existence are real. Emptiness (samadhi) and phenomena are both false, and emptiness and phenomena are also both valid. This is madhyamika, or the Middle Way, where you see that emptiness and phenomena coexist but you don't abide in either: you perceive both realms, but fall into neither. Yes, you rest your mental realm in the quiet of samadhi, and yes, you allow the phenomenal world (including the physical body) to continually transform but without your falling into any sort of clinging to this realm. That which knows is freely born and freely functions, but it doesn't abide in either of these states. It doesn't dwell. There's no affirmation or negation or arguing in this state of attainment, there's just the middle way. This is the true path of observation—observing emptiness and phenomena—the middle way of prajna. And this is also philosophy, science, psychology, and the study of our true ontological essence. But in our explanation, it's just the step of observation. After you understand this, you proceed to another step called “returning,” which means returning to one's original nature, or “original face.” What do you return to? This is hard to explain, so a story will have to suffice.

Bodri, William; Shu-Mei, Lee. Twenty-Five Doors to Meditation: A Handbook for Entering Samadhi (pp. 29-30). Red Wheel/Weiser. Kindle Edition.