If you are not listening closely, very excellent items that could be missed:
- The experiences within altered states of consciousness are not just all "in your head". Receptors in the brain are like keys to locked doors of perception. What happens when the chemical reactions from drugs unlock those keys in the brain, it opens the brain's processing of information to being able to perceive what's already there. A "hallucination" is not purely the imagination, but is an actual reality being processed that once, prior to the novel chemical reaction, couldn't be "naturally" perceived.
- Meaning, both the pursuit of meaning and the desire for significance of meanings, is a product of the ego.