Consider a sympathetic resonator from which you take intensity samples 30 times every second. Now consider that its resonant frequency is 20 hertz. So at each sample you may get an exact number, which depends on all its previous activity, but yet, since a single wave itself is larger than the sampling period, the exact number doesn't have complete meaning. Or the time you sample it at doesn't have complete meaning. Either way you look at it.
This is reminiscent of the Heisenberg uncertainty principle, by which two variables like position or velocity can be individually known but their combined precision (multiplied) can't exceed h/2, and also since it's about waves it alludes to wave-particle duality.
So the two ways of looking at the amplitude/phase problem in the resonator example could correspond, somehow, to the two ways of sampling an object: position, or velocity. A different way of sampling it is a different way of looking at the object.