I outline a heretofore neglected difference between manipulation scenarios and merely deterministic ones. Plausible scientific determinism does not imply that the relevant prior history of the universe is independent of us, while manipulation does. Owing to sensitive dependence of physical outcomes upon initial conditions, in order to trace a deterministic history, a microphysical level of analysis is required. But on this level physical laws are time-symmetrically deterministic, and causality, conceived asymmetrically, disappears. I then consider a revised scenario to resurrect the threat of manipulation even in the presence of time-symmetry and sensitive dependence upon initial conditions. To do so we posit a manipulator containing a...