Essence of Quantum Mechanics :
What cannot be calculated, cannot be measured. What can be calculated, can be measured. And most importantly, not everything can be calculated.
Calculation :
Write a mathematical equation to predict the future state of a system using information about the present and past history. Systems for which this is possible are henceforth referred to as physical systems.
Measurement :
Take a classical system with a calibrated scale. Make it interact with a quantum/classical system, and note the change in reading.
Essence of Physical Science :
This change of reading of a classical calibrated apparatus in a measurement is expected to agree with the theoretical calculation.
