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Visible light is a band from 380 to 700 nanometers.

That's all we see.

Beyond that band — radio waves, microwaves, infrared radiation, ultraviolet, x-rays, gamma rays. All of it exists right now. Around you. Passing through you.

You don't see it.

Not because it isn't there. Because evolution didn't give us that tool. It wasn't needed for survival.

What we call reality is a very narrow band of a very wide spectrum.

The Same Thing. Different Realities.

Take an ordinary flower.

To us it's white. To a bee it's a vivid ultraviolet pattern pointing exactly where to land. One object. Two creatures. Two completely different pictures.

Snakes see heat. They perceive infrared radiation as an image. In total darkness they navigate the world through temperature.

Sharks sense electric fields. Bats build a picture of space through ultrasound. Dogs live in a world of smells entirely out of our reach.

This is not a metaphor. These are different realities from one physical world.

None of them more real than another.

Umwelt

In the early twentieth century, German biologist Jakob von Uexküll introduced a concept that changed biology.

He called it Umwelt.

It's the subjective universe of an organism. The reality it is able to perceive. Not the objective world but a world built from the signals available to a specific species.

A tick lives in a world of three signals. The smell of butyric acid. Heat. The moisture of skin. Nothing else exists for a tick. Not because nothing else is there. Because that is its Umwelt.

Ours is wider. But the principle is the same.

We perceive what we were built to perceive. Evolution shaped our senses for one task: survival in a specific environment. Not for understanding reality as it is.

The first and most important step is to acknowledge that the Umwelt exists. Once you do that, the world fractures, beautifully, into a vast collection of sensory worlds. — Ed Yong, An Immense World, 2022

What Lies Beyond the Filter

Physics describes what we don't perceive directly.

Dark matter — around 27% of the universe. Dark energy — around 68%. Everything we see, feel, measure, everything we are made of — around 5%.

The other 95% exists. Just not in our Umwelt.

We study the universe through tools we built ourselves. Telescopes, detectors, mathematical models. And even through those we only see indirect traces of what is out there.

Direct access to reality as it is: we don't have that. Maybe we never did.

The Filter Is Not a Flaw

We are not broken.

Our filter is precisely calibrated for the task it was built for. It works. It allowed us to survive, build cities, launch telescopes, formulate the physics of dark matter.

But calling that filter reality, that's not quite right.

Reality is not what we see. It's what we are capable of perceiving.

Those are different things.

And that's not a reason for anxiety. It's just an honest look at where we stand. One point of perception. In a very wide spectrum.