“It is a fundamental quantum doctrine that a measurement does not, in general, reveal a pre-existing value of the measured property. On the contrary, the outcome of a measurement is brought into being by the act of measurement itself, a joint manifestation of the state of the probed system and the probing apparatus. Precisely how the particular result of an individual measurement is brought into being—Heisenberg's "transition from the possible to the actual"—is inherently unknowable. Only the statistical distribution of many such encounters is a proper matter for scientific inquiry.”