Look around.
How much does vision feel like seeing through a window to reality — a reality of three dimensions, rich with depth, noise, texture, aroma and color? The universe we intuitively know seems coherent and believable. Objects do not go whimsically changing properties; things stay put unless something moves them, and that cup of hot coffee will always burn like hell if you spill it in your lap. Despite the occasional accident, we navigate and manipulate our world with considerable grace.
At first glance, it seems but too obvious that things exist as exactly how we perceive them, but even a very basic understanding of perception should dispel this popular belief. I’m sure that if probed, most people could correctly identify that every sensation and thought they have ever had is arbitrated at some level by neurons firing in patterns. I’m just here to shake you to your foundation so that you have that “holy shit” moment and realize: our world comes from inside.
Let’s deconstruct the process behind hearing, one of the major modalities of sense, to get a general feel for how the environment stimulates the sense organs.
The interaction of matter produces vibrations that travel through the air. If the vibrations are within a certain frequency range, then they physically affect structures in the inner ear, after which the wave information is converted into impulses in the cochlea. Signals eventually reach the auditory cortex of the brain, where the sensation of sound is produced. From this picture, it seems an inescapable conclusion that noise is not something that exists externally but something absolute that we just pick up on. Rather, there are vibrations that are capable of having a real physical effect, and our sense organs construct the sensation of noise via complex neural networks.
Sound comes from us. If a tree falls in the forest and there is no one there to hear it, it does not make a sound; it makes vibrations. We evolved a mechanism to harness the vibrations (the ear) and a mechanism to interpret of the vibrations (the brain) out of utility. With the right mental tools, sound waves can communicate how matter is interacting, at what intensity, from how far away, in what direction and more.
Hearing provides just one example, but a thorough analysis of the senses will likely lead you to the following conclusion: Perception is a suite of elegant and useful devices of the mind that converts parts of the physical universe into mental representations that evolved because of their adaptive consequences. The physical world is incredibly intricate and complex, and it should be noted that that we have no senses for most physical phenomena, and that there is nothing inherent about what physical phenomenon is used for what representation.
I am convinced that reality is a fundamentally non-perceivable entity. Perception, via the senses or through tools, requires the conversion of information in a domain where infinite conversions are possible. Any time you perceive something, you are collapsing all the other possible ways of representing the same phenomenon.
Reality is for no one.