Horizons are apparent boundaries that constantly shift and eventually disappear entirely through an enlightening vantage point. What the sacred visionary plants do is they show the culturally conditioned boundaries that we have constructed to be pretty flimsy, arbitrary, manipulated and as always sold to the highest bidder. It is a mass consensual hallucination that if not maintained with sufficient attention and participation falls apart like a stock market crash or a bank run. This is the reason that corporations and governments are afraid of the teacher plant. It is the red pill. Once you take it you can still go back to the Matrix, but you can not ever unsee the Truth that you saw while under the effects of the medicine.