Full Idea
In a typical cause-effect situation (a 'propagation') cause must precede effect, for propagation over a finite time interval is an essential feature. In an 'interaction', an intersection of processes resulting in change, we have simultaneity.
Gist of Idea
Cause must come first in propagations of causal interactions, but interactions are simultaneous
Source
Wesley Salmon (Causality: Production and Propagation [1980], §8)
Book Reference
'Causation', ed/tr. Sosa,E. /Tooley,M. [OUP 1993], p.170
A Reaction
This takes the direction of time as axiomatic, and quite right too. Salmon isn't addressing the real difficulty, though, which is that the resultant laws are usually held to be time-reversible, which is a bit of a puzzle.