Brain science has a very long way to go for sure, and legislation had impeded studying certain substances, yes. But there has been research on perception and its limitations and this leads to an understanding where it is not remotely surprising that a substance could cause severe misperceptions undetected by the owner of the brain -- it happens continuously to all brains even when they are not tripping.

I'll juste leave this quote here:

"Isn't it enough to see that a garden is beautiful without having to believe that there are fairies at the bottom of it too?"