The problem of the preferred basis consists in accounting for the basis that defines the measured observable in a quantum measurement, given the supposed theoretical ambiguity in the definition of such an observable. The purpose of this paper is to analyze this scarcely explored problem. The final aim consists in arguing that, contrary to a widespread opinion, the theory of decoherence does not supply a solution to this problem, not due to its own inability, but because the problem is actually a pseudo-problem which does not require a solution.
Measuring apparatus; Environment; Basis of the Hilbert space; Superposition
