  A universal formulation of uncertainty relations for quantum measurements is
presented with additional focus on the representability of quantum observables
by classical observables over a given state. Owing to the simplicity and
operational tangibility of the framework, the resultant general relations admit
natural operational interpretations and characterisations, and are thus also
experimentally verifiable. In view of the universal formulation, Heisenberg's
philosophy of the uncertainty principle is also revisited; it is reformulated
and restated as a refined no-go theorem, albeit perhaps in a weaker form than
was originally intended. In fact, the relations entail, in essence as
corollaries to their special cases, several previously known relations,
including most notably the Arthurs-Kelly-Goodman, Ozawa, and
Watanabe-Sagawa-Ueda relations for quantum measurements. The Schr{\"o}dinger
relation (hence the standard Kennard-Robertson relation as its trivial
corollary as well) is also shown to be a special case when the measurement is
non-informative.
