There are two basic facts that I have difficulty reconciling: (a) the magnetic and electrical components make up a complementary pair of variables (b) Maxwell's equations describe the magnetic component in terms of the electrical one and vice-versa My question is definitely not original and assuredly not even very clever, and so should have a standard and elementary answer out there somewhere. I could formulate it as follows: Suppose one determined one of these components with a measurement. That should make the other one completely indeterminate, including its rate of change. But then what sense would the corresponding equation make? Otherwise put, given a precise measurement of one of the variables, Maxwell's equations should give us the other variable, which is impossible. What is wrong with this formulation? I assume that part of the answer is that the uncertainty principle is a statistical principle, but Maxwell's equations are not, so this makes it even more difficult to fit them both together, even though the Uncertainty Principle, if I understand my history (also not certain), was derived from Maxwell's equations. Thanks for any help.