but timing isn't one of them.

Hm? What Pisani is pointing out here is that of the 3 major causal patterns that a cross-sectional correlation can reflect, A->B, B->A and A<-C->B, a longitudinal correlation in which observations of A are followed by observations of B, will let you rule out 1 of the 3 patterns (B->A), reverse causation, which leaves either the hypothesized direct causation or confounding. This is much better evidence than just the cross-sectional approach, although I think confounding is much more likely in general so the boost is not as big as the trichotomy makes it sound.