  Clarifying the nature of the quantum state $|\Psi\rangle$ is at the root of
the problems with insight into counter-intuitive quantum postulates. We provide
a direct-and math-axiom free-empirical derivation of this object as an element
of a vector space. Establishing the linearity of this structure--quantum
superposition--is based on a set-theoretic creation of ensemble formations and
invokes the following three principia: ($\textsf{I}$) quantum statics,
($\textsf{II}$) doctrine of the number in the physical theory, and
($\textsf{III}$) mathematization of matching the two observations with each
other (quantum covariance).
  All of the constructs rest upon a formalization of the minimal experimental
entity--the registered micro-event, detector click. This is sufficient for
producing the $\mathbb C$-numbers, axioms of linear vector space (superposition
principle), statistical mixtures of states, eigenstates and their spectra, and
non-commutativity of observables. No use is required of the spatio-temporal
concepts. As a result, the foundations of theory are liberated to a significant
extent from the issues associated with physical interpretations, philosophical
exegeses, and mathematical reconstruction of the entire quantum edifice.
