  Retrocausal models of QM add further weight to the conflict between causality
and the possible existence of free will. We analyze a simple closed causal loop
ensuing from the interaction between two systems with opposing thermodynamic
time arrows, such that each system can forecast future events for the other.
The loop is avoided by the fact that the choice to abort an event thus
forecasted leads to the destruction of the forecaster's past. Physical law
therefore enables prophecy of future events only as long as this prophecy is
not revealed to a free agent who can otherwise render it false. This resolution
is demonstrated on an earlier finding derived from the Two-State-Vector
Formalism (TSVF), where a weak measurement's outcome anticipates a future
choice, yet this anticipation becomes apparent only after the choice has been
actually made. To quantify this assertion, "weak information" is described in
terms of Fisher information. We conclude that an already existing future does
not exclude free will nor invoke causal paradoxes. On the quantum level,
particles can be thought of as weakly interacting according to their past and
future states, but causality remains intact as long as the future is masked by
quantum indeterminism.
