  In this article we propose an approach that models the truth behavior of
cognitive entities (i.e. sets of connected propositions) by taking into account
in a very explicit way the possible influence of the cognitive person (the one
that interacts with the considered cognitive entity). Hereby we specifically
apply the mathematical formalism of quantum mechanics because of the fact that
this formalism allows the description of real contextual influences, i.e. the
influence of the measuring apparatus on the physical entity. We concentrated on
the typical situation of the liar paradox and have shown that (1) the
truth-false state of this liar paradox can be represented by a quantum vector
of the non-product type in a finite dimensional complex Hilbert space and the
different cognitive interactions by the actions of the corresponding quantum
projections, (2) the typical oscillations between false and truth - the paradox
-is now quantum dynamically described by a Schrodinger equation. We analyse
possible philosophical implications of this result.
