I have a new-b question. From Dr. Chinese's page I get this quote "EPR had a simple but powerful definition of what they called an "element of reality": IF an observable property of a system could be predicted with absolute certainty (100%) without disturbing that system, THEN it must correspond with an element of reality." My understanding is that it is impossible to measure any property without causing some amount of disturbance. At the macro scale the disturbance is small and the measure accuracy can be high. At the micro scale the disturbance is percentage wise higher and the accuracy is limited. Do I understand the nature of measurement wrongly?