 The laws of nature at the most fundamental level at which they are currently known are combined in the Standard Model of elementary particle physics. These laws are CPT-invariant, i.e., they remain the same under the combined operations of charge-reversal C (replacing all particles by their anti-particles), parity P (flipping the signs of all spatial coordinates), and time-reversal T. The asymmetries in time which are pervasive in our everyday lives are a consequence not of any temporal asymmetry in these laws but, instead, of the boundary conditions of the universe, notably in its very early stages. It seems natural to assume that the time-symmetry of the laws (modulo the combined operation of C and P) extends to causal dependences at the fundamental “ontic” level that underlies the empirical success of quantum theory. If so, there may be backward-in-time no less than forward-in-time causal influences at that ontic level.