[P.O.E.]

Going out on a very slim limb here:

One function it is impossible to calculate is the interaction (or interference, if you will) upon the observed by the observer. Since you can't predict the latter wouldn't you end up with a model that is unstable over time? Or is it merely a function with infinite solutions (or do they only seem infinite?).Either way, it seem incomplete to me.

[snarks_when_bored]

One function it is impossible to calculate is the interaction (or interference, if you will) upon the observed by the observer.

Heisenberg's Uncertainty Principle gives one a quantitative grip on the observer's disturbance of the observed. Take your pick:

Heisenberg's Uncertainty Principle