  In quantum mechanics the deterministic property of classical physics is an
emergent phenomenon appropriate only on macroscopic scales. Lee and Wick
introduced Lorentz invariant quantum theories where causality is an emergent
phenomenon appropriate for macroscopic time scales. In this paper we analyze a
Lee-Wick version of the O(N) model. We argue that in the large N limit this
theory has a unitary and Lorentz invariant S matrix and is therefore free of
paradoxes in scattering experiments. We discuss some of its acausal properties.
