Coming from a Chemistry background, the Uncertainty Principle always seemed to be described as an inability of precision due to strictly physical and real reasons (i.e. you have to interact with an object to measure something about it, and this certainly will alter the object). It seems as if this was historically the original naive explanation of it as well before QM came along in vogue and made us wonder if reality itself was uncertain (in the sense of there not being defined states before measurement). Without a fundamental understanding of what underpinning reality exists (or doesn't), how do we have confidence in the validity of our measurements? How do we know that our measurements are not, via interaction, deceiving us from their true states? I wager I'm missing something from EPR and Bell's here...but I'll leave that gambit open for now. If it helps anyone in explanation or context, I believe thinking of the typical 3-polarizer experiment (two 90 degrees, with one 45 degrees inbetween) was what got me to pondering these concerns.