[heap_perms]

Yes, a substance like LSD can alter one's self-evaluation, but that doesn't negate the validity of the experience. LSD and similar substances offer a unique lens, a radical shift in perspective that can unveil new ideas, hidden patterns. If you get a the message, hang up the phone.

In the end, all ideas have to be measured against all other ideas.

But I suppose what you're aiming at here are objective, measurable results in a scientific context? Well, we have a huge hole in the research body of about 45 years, thanks to criminalization (it is very tedious to get a study approved on a schedule 1 drug). However, in recent years, it seems to be opening up. They call it the psychedelic renaissance. Numerous studies have explored both the subjective effects and the applications in mental health. One that strikes out to me involves testing on individuals attempting to quit smoking. After a year, 80% (!) of the participants successfully maintained their cessation from smoking. [1] This is after a single dose!

Long rant, the point is, there are measurable, real-world impacts that these substances can have.

[1] https://pubmed.ncbi.nlm.nih.gov/27441452/