 Norton (2003) argues that this defense is unsuccessful, since determinism comes under pressure even in what is often taken to be the paradigm of a deterministic theory, Newtonian physics. Norton’s example of an non-deterministic Newtonian system is that of a mass, subject only to gravitational force, initially at rest sitting at the apex of a dome whose height h depends on the its radius r according to \(h=(2/3g)r^{3/2}.\) Norton shows that this system has an infinity of solutions, each corresponding to the mass sliding down the dome in some arbitrary radial direction \(\cdot\) at some arbitrary time T. Hence the system is indeterministic and for each particular solution there is nothing to which we can point as the cause of the mass’s beginning to slide down the dome in direction \(\cdot\) at time T.