  Two typical entanglements will be shown to stand on opposite sides on the
issue of \emph{instrumental realism}, the issue of whether (as for EPR in the
original form or EPRB, Bohm's versions using spin) or not (as for GHZ)
observables have values that preexist measurement. Instrumental realism in the
EPR context helps us prove that in some special circumstances, one can get
simultaneous knowledge of two conjugate quantities, which in particular make
sense together. This shatters the axiomatic presentation of Quantum Mechanics.
This simultaneous knowledge of two conjugate quantities elaborates on 1935 work
by Schr{\"o}dinger, hence the name, \emph{Schr{\"o}dinger Unorthodoxy Theorem},
given to the second main result that is easily deduced from the result on
instrumental realism. Once the axiomatic edifice of Quantum Mechanics is
broken, we can let go the completeness of the wave function as suggested in
EPR, and hold fast on locality. The EPR paper of mid-1935 gets here contrasted,
from a new point of view, with a 1936 text where Einstein avoids using
counterfactuals. Counterfactuals get a precise definition and the corresponding
concept is used all along, but may be new under an old name. We provide a short
critical review of Bell's 1964 paper. Then, a small modification of arguments
for the Schr{\"o}dinger Unorthodoxy Theorem will let appear a simple
conservation law, combined with the Malus Law, as the origin of the correlation
in Bell's version of EPRB: this is our third main result. As the fourth main
result, a last use of the concept of counterfactual yields the decay of
geometry at small enough scale. This opens a new world of interpretation of
aspects of Quantum Mechanics, aspects that range from measurement and the need
of classical physics to views on what realism should mean in microphysics.
