  In this study, I argue that the future is not open if quantum mechanics is
complete. An open future means that the value observed when measuring a
physical quantity in the future is not determined. At first glance, quantum
mechanics seems to support the open future thesis, because it cannot always
predict measurement value with certainty. However, many interpretations regard
quantum mechanics as deterministic. These interpretations only suggest that the
quantum mechanical world can be deterministic. I argue that, although quantum
mechanics cannot predict the future with certainty, the quantum mechanical
world must be deterministic, and the value observed by the observer is
determined. I examine the following two cases: (1) the wave-function completely
describes the physical state and (2) the wave-function does not describe the
physical state. Then, I argue that the future cannot be open in either case
when quantum mechanics is complete.
