Pavel Bona Selfconsistency and Objectification (24K, TeX) ABSTRACT. Three mathematical models of interaction of a ``small'' quantummechanical system with a ``large'' one are presented. It is discussed their possible role in solving interpretation problems of quantum mechanics (QM). The third model determines the (``unsharp'') quantity measured in the described process as a consequence of the chosen interaction of the ``object'' with a macroscopic ``apparatus''. The fourth of the presented models introduces a natural nonlinearity into dynamics of QM; the nonlinear evolution allows to distinguish between the two kinds of mixed states: between the improper ones (called also ``elementary mixtures''), and the genuine mixtures (called also ``Gemenge''). A role of ``selfconsistency'' in trials of interpretation of QM as a universal theory is briefly discussed. The paper contains some remarks connecting the ``objectification problem'' of quantum measurement theory with the problem of universality of quantum mechanics.