The Buddhist scriptures say that the five aggregates are empty. What do you mean by five aggregates? What does observation mean?

Five elements: color, acceptance, thinking, action and knowledge. The first color refers to matter, and the last four are all spirits.

Observation: observing things in meditation, without doping your own thoughts and behaviors, can reflect phenomena and essence just like a mirror, but the difference is that it is reflected with a pure heart, so it is called observation.