"The third possibility is the one that really intrigues me. A 2011 study found that a single dose of psilocybin could permanently increase the personality dimension of Openness To Experience. I’m emphasizing that because personality is otherwise pretty stable after adulthood; nothing should be able to do this."
The fact is everything IS able to do this and it's up to the person to choose it. Most people don't.
The idea that personality is a stable feature after adulthood is simply a cultural phenomena. As a person who has accidentally/intentionally constructed different identities with different voices in the head after out the mouth, it's very clear to me people's identities are incredibly malleable and most people are simply unaware/unpracticed in how to do it.
No it's not. Twin studies show that personality is largely genetically determined, ie. twins that were separated at birth and raised separately largely have the same personalities, levels of happiness and life satisfaction, and even similar jobs and spouses. People tend to overestimate environmental influences.
Gene expression is controlled via the epigenome, which can be affected by trauma.
Why can't it also be impacted by healing?
Also, since you didn't answer the question I asked, it's not a sufficient answer. I'm not talking about tabula rasa. I'm talking about static vs dynamic personality.
That article gives examples of folks who most definitely were not using psychedelics safety. Timothy Leary is famous for his controversial experiments.
Moreover, LSD and mushrooms are often conflated in discussions like this, but it should be noted that the two drugs have widely different outcomes and safe usage parameters.