the mind contains the world

A point made by NameRedacted in various talks, e.g. The World is Inside You (also the 'emptiness of perception' described by Dan Brown):

We tend to think that your mind lives inside your brain, which is inside your head, which is inside the room you're in, which is inside the world. But that's all wrong. Presumably there is an external world, but we never perceive it directly - the only things we are aware of are mental representations. Whatever view you have of the 'world', 'room', 'head', or 'brain' is a representation arising inside the mind.

The waking world is fundamentally like a dream --- anchored to sensory data, presumably, but fundamentally an experience occurring in the mind. How else could experience occur?

On even a moment's reflection it's pretty clear that we're not seeing things "the way they really are". Physics tells us that matter is mostly empty space, yet objects appear solid. Physics describes a continuous spectrum of wavelengths of light, yet objects appear colorful. Physics doesn't even particularly describe objects, just a constantly evolving wave function over vibrating particles, yet objects appear. What we "see" is not the world itself but a set of inferences in a latent variable model, parsing a limited sensory stream in a highly contingent way.

I don't think it's really possible to argue against this point, but it is possible to view it as pedantic. Sure, we have perceptual systems, we view the world in concepts and categories - so what? Representations are useful; loading ourselves down with more layers of "well actually, what's really happening is …" boilerplate that we need to skip over to get anything done is not. Maybe there are practices you can do to train yourself to see the whole world as a dream, but why on earth would you want to make yourself crazy that way?

The big answer to that question seems to be that this illusion of duality, a distinction between self and other, is one of the barriers to awakening --- and so it must be seen through if we are to gain profound liberation. But I don't think that's persuasive to someone who hasn't already bitten that bullet. What do we gain specifically? Are there benefits to such practice on its own (increasing concentration, clarity, or equanimity)?

To me the main benefit of taking this view (which is perhaps pretty weak) is that, even if there are no immediate practical benefits, it brings us closer to the ideal of "seeing things as they really are". The surprising thing is what it implies about the richness of the mind. There is so much subtle detail in our experience of the world --- much higher-def than even a high-def movie. How could a simple brain have the capacity to render so much detail 'internally'? To be fair, it's probably not all internal; the waking world likely is higher-def than dreams in important ways because a lot of computational work (raytracing, fluid dynamics, seeing the output of computer screens as they factor large numbers, etc.) and information storage (the exact topography, locations of every object, details of texture, etc) is offloaded on the external world. But everything about our experience of the world --- our senses of color, texture, depth, motion, object segmentation, interestingness, beauty, etc., at each pixel at each waking moment --- really is an internal representation. And this is all constructed absolutely effortlessly (at great metabolic cost, maybe, but it's not subjectively difficult). I'm not sure yet if this points to anything concretely useful, but it's impressive.