I'm sure this has been asked before, but I've been searching for a clear answer as to why the Uncertainty Principle is a representation of physical reality and not just a result of our imperfect measuring techniques. Is an electron still considered to be a discrete particle orbiting the nucleus, or is the distribution of probability wave an accurate representation of how the atom physically exists? I understand that the act of measuring an electron's momentum will decrease the accuracy to which we can measure its position (and vice versa), but how does the electron cloud physically exist at any moment in time? With the electrons as discrete particles, or as a distribution of probability? Also, I'm pretty sure that protons and neutrons are actual spherical objects. Is the same true for electrons, or is this an unanswered question?