From what I gather it seems like it’s just based on what they experience through meditation, which to me is more like just making claims based on how a certain process made you feel. Like how if you work out enough then things aren’t as heavy anymore, but just because you can lift X doesn’t mean other people can. Though this is quite different.
I know meditation rewires the brain and that in the lab these “experiences” meditation followers and gurus have can be replicated by stimulating certain areas with magnets. Now I don’t think that Buddha or whoever in the past could have known this so it was likely that they thought their method (which to me seems like a guess at seeing what “true” reality is, I mean if you don’t know what the destination looks like then how will you know if you got there? It seems like people tried a bunch of different things and if they were altered by them then they believed that to be true). It would explain why most of their evidence is ultimately falling back on to mystical experience (similar to LSD and psychedelic users), but as science and psychology can attest to MULTIPLE times personal experience isn’t a reliable method of data or even very good. It’s all we have. I don’t see how meditation makes the world any clearer than what we see now. Granted they say it removes all the constructs and boundaries and concepts that our minds make, but to me it just sounds like it alters your VIEW of things but it doesn’t make said view any clearer. A tiger is a tiger whether I have a concept of it or not and whether I have a word or not for it. It eats meat, lives in certain areas of the planet. None of that changes just because I throw away “constructs” and “concepts”. It isn’t a “direct experience of reality, unmediated”, it’s just you believing that. Reality is mediated by our senses and even those aren’t complete. It just seems like they are making a bunch of claims based on the outcome of a practice.
But the worst part is that they just won’t listen to criticism of their ideas. It’s branded and “mind or egoic or conceptual”, when really it’s just pointing out the holes. Science has shown me that there can be more than one factor influencing and outcome or even something we don’t know. Granted maybe their practice does bring peace of mind, I don’t really doubt that. I just doubt the truth of their alleged “insights” that bring such peace. The claim that you are the universe isn’t really true even by physics standards, at best you are a speck in a sea of infinity. It’s even more telling when they try to “scare” you by saying that if you believe you are just a body and will lose all when you die. The alternative is their viewpoint which is infinity, deathless, saying that death is an illusion, that consciousness doesn’t reside in the brain (which to me is based on old mystic ideas about perception. My guess is that they believed the universe was conscious because stuff happens in our awareness, so in order for things to happen they must be held in awareness, ergo Universe is conscious.) But recent evidence does imply consciousness emerged, that it is part of the brain and based in biology. I would know because under general anesthesia I blinked and the whole thing was over, yet I spent over an hour with 0 awareness of anything. No blackness, no dream, nada. Probably why it felt like a blink.
It just reminds me of a common trait among humans, the desire for immortality or not to die. My guess is that these mystics aren’t different from others in fearing death. Why else call it an illusion? Or believe that you are immortal? It would explain their sense of peace, but I can’t directly prove that. My point is that I don’t truly believe their stuff, but it was hard to get over giving them the benefit of the doubt.