  The observer effect in quantum physics states that observation inevitably
influences the system being observed. Our proposed epistemic framework treats
the observer as an integral part of sensory information processing within
entangled quantum systems, highlighting the subjective and probabilistic
aspects of observation and inference. Our study introduces a hierarchical model
for fuzzy instance classification, which aligns sensory input with an
observer's pre-existing beliefs and associated quantum probability-based truth
values. Sensory data evolves via interaction with observer states, as described
by the Lindblad master equation, and is then classified adaptively using
positive operator-valued measures (POVM). Our parametrization employs measures
of concurrent similarity and dissimilarity, facilitating perceptual
associations and asymmetric cognition. The observer's position on a
skeptic-believer spectrum modulates ambiguous matching of noisy perceptions. We
show that sensory information becomes intricately entangled with observer
states, yielding a wide array of probabilistic classification results. This
framework lays the groundwork for a quantum-probability-based understanding of
the observer effect, encouraging further exploration of quantum correlations
and properties in cognitive processes.
