For me it’s time signatures in music. I grew up playing instruments, played in several orchestras, etc. But no matter how many times someone tries to explain time signatures to me, it makes no sense. I don’t understand why people place such importance on it. To me, notes have a pitch and a duration, maybe some dynamics. That’s it. I don’t understand why people try to needlessly complicate it. It doesn’t give you anything.
My wife will hear a song and go “Oh neat, it’s in 5/8.” And I’m like “How tf do you know that, and why does it matter?”
The behavior of quantum systems are just holistic and respond to a de-localized property called quantum mutual information, which is a quantifiable property from the whole structure of the experiment.
If the particle passes through the slits, if there is QMI established between its position value and something, its dynamics change than if there was no QMI.
You can replace the measuring device with a single additional particle that interacts with the one going through the slits such that the QMI between them becomes maximal and it has the same effect as measuring.
That’s because the whole point of a measuring decide is to establish a correlation between itself and what it is testing to measure, so as a consequence any strong measurement establishes maximal QMI between the measuring device and what is being measured.
And since the dynamics of the system depend upon that quantity… it has the effect of altering its dynamics.
The position/momentum thing isn’t just about a difficulty in knowing the position and momentum at the same time. The Kochen-Specker theorem rules that out. The difficulty is that it cannot actually have both properties at the same time. Either one is emergent from the other, or they’re both emergent from a third property, like the configuration of the field.