In the contemporary debate between determinism and indeterminism, quantum mechanics are used by libertarianists, both as a resource to escape the determinism imposed by classical physics, and as a tool to search for a ground to the possibility of free will and moral responsibility. This paper will show that every defense of free will based on quantum mechanics has to overcome at least two objections: on the one hand what I have decided to call the scale principle, and, on the (...) other hand Robert Kane´s luck principle. As will be shown, to answer the first objection does not imply answering the second. Through an analysis of the most recent proposals attempting to solve the latter, this paper will try to conclude that none of the proposals offers a convincing explanation of how quantum mechanics can help to solve the problem of free will. Instead, quantum mechanics seem to contribute to its complication. (shrink)