First of all, thank you to all participants in the ongoing conversation. Your input is greatly appreciated and it perfectly illustrates the different interpretations that I encountered while writing the OP. I am going to let you fine people continue your discourse along the multiple tangents that you are on. It is interesting to discover the landscape of reasoning that they reflect on.

Generalization is indeed a tricky business. I tend to regard it with deep suspicion, especially in the context of philosophy. The disagreement about certainty and uncertainty seems to me to be a case where generalization has generated a furious and false debate. It sweeps differences aside and makes them hard to see. No, I'm not saying that all generalizations do that. I am saying that some do, and it's not helpful. — Ludwig V

So this goes back full circle to the main intent of my OP. I wanted to show this tension between reality as it is and reality as we understand it to be.

Agreements are impossible without an alignment of understanding.
Understanding is impossible without generalizations.

I think you are right about the false debate generated by generalizations, because the whole debate is meaningless. There should be no disagreement about certainty and uncertainty, because they should not be treated as mutualy exclusive opposites. Rather they should be viewed as conceptual extremes that define a field of tension between them, like a spectrum.

It is "our job" to come to an understanding by finding each other on this field of tension. By taking the same position on this spectrum, we come to a shared understanding. It should be obvious that
this position is a volitile one, that will require continuous adjustment and refining to fit the pragmatic narative that lies at its foundation.

Refutes itself. — 180 Proof

Yes, in a way it does, but as I said: what we call truth is in fact a suspended medium. We call it truth but held to the light, we can see the cracks. We just choose not to do that for pragmatic reasons. And that is totally fine by me.

metaphysical statements are not true or false, they have no truth value — T Clark

I agree. There is no such thing as truth. The best we can do is come to an agreement and call that "the truth". In actuality it's more like a placeholder, like a suspended version of truth.

What you are describing sounds like a social contract*1, in which what we both see is real, and what we individually imagine is ideal or unreal — Gnomon

Yes, in subsequent chapters I will illustrate that the social contract is a conditio sine qua non. Without this, no 2 individual entities can relate to one another. The danger for misunderstanding is always there, but so is the opportunity for refinement. In the end, the result will always be pragmatic, never ideal.

"What is real?" is a metaphysical question. It doesn't have a correct answer. Is the quantum wave function real? Of course it is. Of course it isn't. It all depends on where we stand, what perspective we take and that depends on the problem we are trying to solve. — T Clark

Hello there, and thanks for your kind words.

I agree that there is a myriad of perspectives that we can take. I want to examine what these perspectives tell us not only about reality, but also about what false beliefs we have adopted in order to make sense of the world. I want to investigate how much bagage we can shed, before we get lost or loose ourselves. And whatever the case might be, so far it looks like most of what we believe is simply a fairy tale.

What is matter? Matter is something that has the characteristic of mass. When you apply a force to something with mass, it accelerates. That's how you can tell. — T Clark

Now this is a problem, disguised as a party trick. When we talk about matter, we talk about something substancial. Yet, what you do here is defining matter as being completely described by the characteristic of mass. A characteristic is just a number with some corelations to other numbers (characteristics). So the whole concept of substancialtity gets lost in the process.

This is exacly what I am trying to get to: matter is a concept and therefor the whole of reality is conceptual. Not only in our head, not only in the way we perceive and interpret things, but from the outside as well as from the inside. The exterior reality has to be itself an expression of something even more fundamental. As far as I can understand, that something is the principle of the laws of nature and the natural order. I'm still thinking through that one.

@Prometheus2

What and how much exactly do these unique perceptions of beauty of individuals have in common and why? — Prometheus2

Dr. V.S. Ramachandran, Director of the Center for Brain and Cognition and Distinguished Professor with the Psychology Department and Neuroscience Program at the University of California.

In this 1 hour long talk, dr Ramachandran explains in his typical humorous way how strucures in the brain give rise to our experience of beauty and aestetics. I think this is what you are looking for.