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Comment by Waterluvian | Hacker News Reader

I studied remote sensing in undergrad and it really helped me grok sensors and signal processing. My favourite mental model revelation to come from it was that what I see isn’t the “ground truth.” It’s a view of a subset of the data. My eyes, my cat’s eyes, my cameras all collect and render different subsets of the data, providing different views of the subject matter.

It gets even wilder when perceiving space and time as additional signal dimensions.

I imagine a sort of absolute reality that is the universe. And we’re all just sensor systems observing tiny bits of it in different and often overlapping ways.

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> My favourite mental model revelation to come from it was that what I see isn’t the “ground truth.” It’s a view of a subset of the data. My eyes, my cat’s eyes, my cameras all collect and render different subsets of the data, providing different views of the subject matter.

What a nice way to put it.

> I imagine a sort of absolute reality that is the universe. And we’re all just sensor systems observing tiny bits of it in different and often overlapping ways.

Fascinatingly this is pretty much what Advait Vedant (one interpretation of Hinduism) says.

Alan Watts has talked a lot about this topic, if you’re (or anyone else is interested) his stuff is a more comfortable place to understand (compared to classical texts).

And not only that, our sensors can return spurious data, or even purposely constructed fake data, created with good or evil intent.

I've had this in mind at times in recent years due to $DAYJOB. We use simulation heavily to provide fake CPUs, hardware devices, what have you, with the goal of keeping our target software happy by convincing it that it's running in its native environment instead of on a developer laptop.

Just keep in mind that it's important not to go _too_ far down the rabbit hole, one can spend way too much time in "what if we're all just brains in jars?"-land.

> I imagine a sort of absolute reality that is the universe. And we’re all just sensor systems observing tiny bits of it in different and often overlapping ways.

https://en.wikipedia.org/wiki/Phenomenology_(philosophy)

https://en.wikipedia.org/wiki/Transcendental_idealism

Yup. I had the same revelation when I learned that many of the colors we perceive don't really "exist". The closest thing to hue in nature is wavelength, but there is no wavelength for purple, for example. The color purple is our visual system's interpretation of data (ratio of trichromatic cone cell activation). It doesn't exist by itself.

It's the same reason that allows RGB screens to work. No screen has ever produced "real" yellow (for which there is a wavelength), but they still stimulate our trichromatic vision very similar to how actual yellow light would.

All colors exist. Color is not the same as wavelength, color is the human perception of a collection of one or more wavelengths of light. They are all real.

I think this very quickly gets into semantics and then philosophy to the point that it’s not really a useful thing to disagree on.

We can objectively measure the properties of the radiation reaching eyeballs and we can detect sensor differences in some eyeballs in various ways. But we can’t ever know that “red” is the same sensation for both of us.

The concept of “red” is real, made concrete by there being a word for it.

But most colours can be associated with a primary wavelength… except purple. So by that definition, they don’t really exist.

> But most colours can be associated with a primary wavelength… except purple. So by that definition, they don’t really exist.

And white, and black. Physically, you'll always have a measurable spectrum of intensities, and some such spectra are typically perceived as "purple". There's no need to pretend that light can only exist in "primary wavelengths".

Even if there's no empirical way to extract some 'absolute' mental notion of perceived color, we can get a pretty solid notion of perceived differences in color, from which we can map out models of consensus color perception.

That‘s exactly what I thought I had said. Something might have gotten lost in translation, sorry bout that.

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