I'm not disagreeing with the application, just that it is imaginary.
"Imaginary" is just a misnomer. The fact that they describe very real phenomena in reality shows this. A number of figure isn't defined as "real" because it represents a quantity (like 1, 2, 3, etc), but rather because it's an objective description of reality which imaginary numbers are as well.
I you're arguing that imaginary numbers, are not imaginary... I don't really know what to say here. Imaginary is a description of what they are. We literally use imaginary numbers, that we define as imaginary, to make sense if certain equations that pertain to reality. Like we could NOT make sense of everything in reality using only real things, so we had to invent/discover imaginary parts of equations, that cannot be explained by real ones, in order to solve those equations. The thing is, I'm picking kind of a funny(but relative) point here, but there is literally no way to prove that you or I see the same reality or that either is the real one. There have been scientific tests over time trying to figure out if people perceive the same things in reality, and lots of times, everyone's perception of reality is different. Furthermore, there is also literally no way you can prove yourself right, whereas, there are literally thousands of events/pieces of evidence that argue that you're wrong. Not a personal "you," just stating that no one can prove that any reality is the right one. We just kind of have a mush of communal ideas.
Imaginary numbers are just as real as logic is. Sure, there's no physical qualities to them (with the exception of neurons thinking about either one) but they still describe reality objectively. Here's the thing with the concept of differing perceptions. For sight, photons of a fixed wavelength bunch off of surfaces, enter into our eyes and reach our optic nerves which are then processed to create the perception of color. These mechanisms are fixed across all humans. The wavelengths are constant, the method of interpreting this data is constant. So the only disconnect here is "what if the color I see is different than the color you see?" At this point science has come short of showing the connection between cognition and neurology, but the point remains the same: If everything in this line of causation is constant, why should we assume that the last part (the perception) is relative? "Don't add quantities unnecessarily" i.e. Occam's Razor. Sure it can't be "proven" as of this point in time, but what's more likely? That causation remains constant or that the last event in that chain somehow changes person to person? Furthermore, you have to prove the assertion that there's some mechanism in the brain that is allowing for these otherwise objective measures (wavelengths) to be perceived differently per person. "What you freely assert, I freely dismiss. As for those scientific tests you mentioned, without seeing them my self (which I would like to if you could link me, sounds interesting) I'm sure they're something along the lines of "I see this as a bunny, but you see this as a rabbit" or "that looks pink to me and purple to him." At that point, that's just a matter of the state of the brain of the individual being different at some point during that chain of perception. No, I don't have the neuroscience behind that, but it's a rather reasonable assumption. Also, to say that there's far more evidence "proving" that everything in reality is relative is faulty for two reasons: first, there's just as much work proving otherwise from philosophical writings and second, to "prove" anything assumes some objective constants which results can be measured against.
I didn't say prove either way, only argue lol. You can't prove that our perception of reality is the same. Every brain constantly makes assumptions about what it sees, how do you know which brain is right. Also, aren't w technically like 99% empty space when we get down to our atomic structure? I don't perceive myself as that much empty space. Also aren't sound and light the same thing just much different frequencies? So what is reality and why do we perceive it so differently than it is in actuality. Part of reality is perception of the world, an everyone has a different perception of the world and people, partially based on experience, and partially based on genetic makeup. I can't prove that we see different realities but I'm fairly certain we do just based on this interaction, and I know that I see reality differently than people who are color blind. You should look up the Ted talk on Neil harbisson and how he listens to color and paints music, really interesting way to perceive color.
We know what is the true reality because of what you just said your self: The brain makes assumptions. We are aware of this shortcut and the ignorance that arises out of it. Due to this, we can eliminate these shortcuts and see reality objectively. To use the example you brought up: we are mostly empty space, correct. When I look at someone I don't see that. But that's due to our shortcomings in our sense organs like eyes. That being said, the fact that you know that we're mostly empty space hurts your arguments for two reasons: first. you're acknowledging this as objective fact, thus proving objective reality; second, we have a means of finding out what this objective reality entails through instruments that extend and perfect our faulty sensing organs. Sound and light are different btw. Light is made of photons, sound is made from fluids compressing at a certain frequency. Additionally, the fact that many people perceive reality differently doesn't mean reality is actually what we perceive through our sense. Our brain takes shortcuts all the time which is why we see faces in trees and animals in clouds. But we know objectively that not only our brain is taking shortcuts, but that reality is different than that misinterpretation. We can do this by, as stated above, instruments that extend and perfect our senses. To emphasize further, reality is not shaped by perception. Sure quantum physics acts a little weird, but we still have more research to do there. That being said, if a tree falls and no one is around, it still makes a sound. It's quite a hubris statement to say that reality is defined by our perception. With that cleared up, multiple perspectives doesn't mean that there are more than one realities. Finally, we know that color blind people or others who see music and feel light are experiencing reality differently, but again, we know what is objectively happening: Their brains are taking in objective physical phenomena like light and sound waves in different means than normal. But the physical reality of the objects remains objective and thus, reality as well.
Light and sound are both vibration. Also, the question was whether we see reality as it really is...
Light is electro magnetic radiation that has wavelengths. Sound is a vibration that propagates as a mechanical wave. Very different in nature. And earlier you were talking about how we perceive different realities implying there are more than one. That's confusing a misinterpretation of reality with there being more than one. Due to our limitations from our sensing organs, the truth is the earlier rather than the latter.