Though there's much not to like about the way I wrote down some thoughts on intelligibility a year ago . There's one thing in particular that stands out. If I have one thing and I make a perfect copy. Surely I now have two things which are perfectly "the same", right? The idea being that, if you can even point and say that there are "two things" and you can distinguish between them. That shows exactly at least one way in which they are not the same. And if you'd like to be able to say they are "the same" - you need to ignore that difference.
Alright, that's all well and good. But what does that actually usefully mean without being so vague?
Let's take two copies of our binary number.
Are they the same? Well - no, not really. Clearly they're different with respect to the yellow direction. Are they different? Well - no, not really that different. Only on the yellow direction.
If I couldn't see a difference between "the two", I would just see this .
Alright, this might start to give you an impression. But let's keep expanding on this kind of idea. What I'm basically saying here, is that in order to point out some symmetry, invariance, ..., equivalence, I need access to some asymmetry, variance, ..., inconsistency. Or again this thing of, in order to point out some way in which they're the same, I need access to some way in which they're not. Or slightly rephrased; if I cannot see a difference, it will look the same to me.
An example of this might be a tautology. A tautology doesn't generally hold up. In setting up a tautology, there must be an asymmetry in order for me to point out which two things are supposed to represent the same thing. The reason why that doesn't matter for most things considered tautologies, is that this inconsistency is just deemed an irrelevant detail. This asymmetry can be ignored. And hence, if we allow for the ignorance of this difference, a tautology holds: "of course they are the same" - if you ignore the difference, that is.
It's quite easy (in general) from either perspective, to ask what it would mean to change perspective, as it were. Since changing perspective is just adding, removing, ..., changing structure. From the perspective which only sees a binary number, we could ask: "What if I saw this thing as three possible options?"
The consequences, accuracy, implementing, ..., finding (of) such a change however - for some other thing one is interested in, is not at all trivial. Why is that the case?
Take again, the example of two points without structure, whose structure we don't have access to, ..., whose structure we're ignorant of.
From this perspective it seems simple to equivalence, assume (simultaneity, ..., invariance), ..., ignore the difference between the two. The only thing we need to destroy is one connection, and we get:
Similarly, from this perspective it seems quite simple to grow back to the other structure. We only need to introduce some inconsistency, assumption of (non-simultaneity, ..., variance), ..., difference.
These two perspective are obviously already possibly inconsistent with each other. But why this is a hard problem, is because one might find additional structure, ..., ignored structure at each of the points. And it's not necessarily obvious what to do with that.
Say we wanted to assume some equivalency between these two.
There are many things I could mean or want to do with that.
I could still have access to this same structure, but only accessible from a different perspective.
I could say, "oh, the one is red, the other is blue", and they must be *the same kind* of red and blue. And so surely, if we ignore the difference between the two, that could be interpreted as a superposition.
I could just destroy one of them completely, as I would have done from the perspective of being ignorant of additional structure. (The two yellow points above, which I just merged to one)
This could frankly be anything. If it can be constructed, this is valid way of equivalencing the two. So this, is a perfectly reasonable way of equivalencing our red and blue points:
Another way of thinking about this, is that an equivalence and an inconsistency aren't actually different things at all. And that concepts like equivalence, ignorance, renormalization, coarse-graining, ..., inconsistency can all be used somewhat interchangeably. And I need additional structure to distinguish between them. They don't generally hold up. This might fly a bit in the face of how you usually use words, but let's entertain it for a moment, and see if we can disentangle what I could possible mean by that - without descending into vague madness.