 Another problem for Mackie’s regularity theory is that the complex regularities seem to be symmetric. This symmetry blurs the asymmetry between cause and effect, and leads to the problem of the direction of causation. Like Hume, one could stipulate that causes precede their effects in time. The direction of causation is thus simply the direction of time. However, this stipulation excludes both the possibility of (a) backwards causation and (b) an analysis of “time’s arrow” in terms of causation. Since—to the best of our knowledge—there is no account of causation which has fully solved the problem of the causal direction, the objections (a) and (b) do not speak decisively against the regularity theory.