It is important to point out that the idea that hallucinations are a product of the brain over certain chemistry, does not make sense according to the very nature of the brain and other organs. let's start by pointing out that both the brain and the eyes, ears and other organs are linked to an analysis of dependence from external reality. that means they don't produce anything they capture. some may blame chemistry for changes in perception, but this is again a mistake, for that would be to say that the brain, like other organs which are of a receptive nature, are self-sufficient. the problem with this argument is that if they were, it would go against their very functional nature, and therefore, they would be obsolete. we see then that solipsism would be the real cosmic vision, which would break with all questions. The most interesting thing is that for hundreds of thousands of years, hallucinations were treated as events related to objective reality. It was with the rise of the Enlightenment, and also with scientism, that it came to be criticized as an objective experience, and treated as a simple product of the brain, which is not true. the origin of this change is due to a need of intellectual systems, to limit the perception of reality, which goes against the very essence of the cosmos, which is unlimited in essence and manifestation, just see that we cannot detect more than 99% of the things that are happening around us. this is very important to understand, because it determines that something is activating these perceptions and this is totally beyond human control. another important thing is that the drugs probably activate with their chemistry the possibility of perception within the capacities of the organs, thus creating color variations and so on. To say that the brain produces things like hallucinations is literally advocating solipsism and being an escapist. Some may invoke the property of medical science for the debate, but it is extremely limited, the greatest proof of which is the fact that, even today, science cannot define exactly what life is. the truth is that we have nowhere near a coherent perception of reality, and perhaps, coherence is actually the problem itself.