  We start with methodological analysis of the notion of scientific theory and
its interrelation with reality. This analysis is based on the works of
Helmholtz, Hertz, Boltzmann, and Schr\"odinger (and reviews of D' Agostino).
Following Helmholtz, Hertz established the "Bild concept" for scientific
theories. Here "Bild" ("picture") carries the meaning "model" (mathematical).
The main aim of natural sciences is construction of the causal theoretical
models (CTMs) of natural phenomena. Hertz claimed that CTM cannot be designed
solely on the basis of observational data; it typically contains hidden
quantities. Experimental data can be described by an observational model (OM),
often on the price of acausality. CTM-OM interrelation can be tricky.
Schr\"odinger used the Bild concept to create CTM for quantum mechanics (QM)
and QM was treated as OM. We follow him and suggest a special CTM for QM,
so-called prequantum classical statistical field theory (PCSFT). The common
interpretation of the violation of the Bell inequality is criticized from the
perspective of the two level structuring of scientific theories. Such critical
analysis of von Neumann and Bell no-go theorems for hidden variables was
performed already by De Broglie (and Lochak) in 1970s. The Bild-approach is
applied to the two level CTM-OM modeling of Brownian motion: the overdamped
regime corresponds to OM. We briefly discuss ontic-epistemic structuring of
scientific theories (Primas-Atmanspacher) and its relation to the Bild concept.
