As it is well known, the measurement problem is a long-standing problem regarding Quantum Mechanics or, at least, of its interpretation. Roughly speaking, the measurement problem arises from the transition of a system in Quantum Mechanics from a superposition state to a definitive state. That is, how a system transforms from being in a “quantum state” to being in a “classic state”. As is also well known, there are several attempted solutions to the measurement problem. Despite the vast array of options, most of the solutions presented assume that classic entities or properties are metaphysically reducible (or identical, in some cases) to quantum entities or properties. Nevertheless, maybe we can question this micro-reductionist assumption, and perhaps this assumption is what makes the measurement problem, problematic. This paper aims to analyze the micro-reductionist hypothesis, its historical origins, metaphysical support and consequences to the historical formulation of Quantum Mechanics.