  Do such cases genuinely count as downward causation in, for instance, Kim’s (1999) sense? After all, strictly speaking, the idea that causation is synchronic across the whole and part of the same entity seems contradictory. Soto and Sonnenschein accept this criticism, and propose that the kind of causation they are invoking is not synchronic, but “diachronic emergence”:  “cellular and tissue events occurring before the expression of a particular set of genes takes place may act downwardly modifying the expression of these genes at a later time” (Soto, et al. 2008, 271).