I did some spelunking as a teen (lived in an area with 100+ caves), and you sometimes heard about stone blocks ramming down with climbing speleologists in large underground halls, higher levels of carbon dioxide preventing breathing or sudden flash-floods preventing escape. Not so much about sudden cave collapses (I guess in earthquake areas that's always a possibility).

When I was in the dark, squeezing through tiny holes in various angles, I felt a bit like having an "out-of-body" experience, where my brain visualized my whereabouts in some kind of 3D map and internally I was looking at the whole 3D map "from outside"; like viewing an autonomous robot making its moves. It was quite fascinating. I guess sensory deprivation allowed the "3D mapping signal" to be perceivable and dominant.

Also, given there is no smell inside caves, if you spend a few hours/days inside, then climb back to surface, upon entering ground you are hit by a wall of smells you never perceived before. Suddenly you can distinguish individual flowers, trees, grass, soil etc. That however only lasts a few seconds :-(

Your visualization experience sounds very interesting!

I actually believe it is possible to consciously 'do' what you describe to at least some degree. It would be nice to hear more about your experience in detail, may I ask you some questions?

Was it as vivid and sharp as daylight open eye view or was it rather blurry / fuzzy?

Where the colors saturated or rather gray?

Was every action instant or was there a time lag?

Did the shapes stay stable or did they deform or fade after a time [of no new inputs (from touch I guess)]?

What did it look like to touch a wall?

How would you describe the field of view you had in your visualization? Normal? All-Round-View onto the 3D map?

Did you have a feeling for the volume where the field of view of your body would be?

How did you visualize your body? Abstractly or more like you might look in daylight?

Could you move as observer in your visualization or was that out of your control?

Well, it's not like I didn't perceive stuff with my eyes, it's just that I also internally had another view (I still have some fragments fairly vivid in memory), where I could kinda rotate my view, e.g. being inside a tunnel with irregular slopes hinting at some abyss through cracks at the bottom and I viewed it inside as a certain irregular shape I could rotate, localize me (where "me" was some uncertain blob and my pose was how my body was reporting to me, but my overall shape was just fuzzy/unimportant) and do some planing. As for colors, again unimportant, not sure if there was even a concept of color in my internal representation. Actions as such were instant, but the feedback was basically tactile/otolithic, updating my location/pose estimate. FOV was variable, changing as I needed and as I moved inside visualization. It might have been inspired by some speleology mapping tools that at the time started to become 3D, so my brain might have used a similar representation.

I guess it was really dampened sensory inputs, not dominating perception as usually, that allowed this kind of planing/internal model to come out. Without spelunking I'd probably use it only subconsciously in sports like when hitting a tennis ball at 120mph and planning all moves in advance, serving a sneaky ball in volleyball etc. I had a similar feeling once when a car that was joining my road almost rammed into me and I just remember that my brain switched to 100% focus and almost automatically did all the crash avoidant tasks where I felt more like an observer, and the calculation was perfect (i.e. no crash).

Thank you that was a very interesting read. It sounds similar to how I imagined it.

Sometimes I ask myself if this is similar to how blind people visualize their world. I remember reading from Hellen Keller (deaf-blind from birth) that she also had a visual representation of the world around here. Something along the lines of the human brain is just build for this kind of representation.

I think that there is some common underlying representation that everyone uses. When seeing something through the eyes this representation is overlayed with salient visual sensor input in eye fov and our internal fov just focuses on this for convience and because it is so damn salient. I think it is possible to detach the internal fov from the eye fov and see how the brain models the other regions.

Your suggestions that sensory deprivation brings out the underlying internal representation is very intersting. It makes a lot sense! Really gotta try that sensory deprivation chambers some time =)

You live in a universe where astronomical events lightyears away can obliterate life on earth with no advance warning whatsoever. Being in control is an illusion.

The fact that all life on earth could theoretically be snuffed out without warning doesn't mean there aren't more mundane terrestrial factors that we can control, and should, assuming you're into things like comfort and survival.

Oddly, this reminds me of my mild fear of driving. I can't ignore the fact that at any moment while driving, I or anyone driving near me could apply a few paltry newtons of force in a way that causes massive injury and destruction, changing or ending lives. Every time I get behind the wheel, I have to wonder at how casually I'm about to pilot a huge mass at lethal speeds around hundreds of other people casually doing the same thing. There's nothing I can directly do to affect the mistakes of others, but I accept the risk of freak accident and resolve to do what I can to at least reduce the risk of disaster (drive defensively). Analogously, we all accept the (demonstrably small) risk of annihilation by, e.g., gamma-ray burst, and go about our lives.

> Being in control is an illusion.

It is a very useful illusion though. I take it as a sort of veneer that the brain hoists over our eyes to make day to day life bearable. There is some truth to the saying "Ignorance is a bliss".