Every hypothesis has to be tested after the processes that are involved have occured.
Every test is performed on data that have aleady been collected.
Repeatability is not the only criterion for falsifiability. He was talking about natural selection. Let me give some real examples. Conservation biologists have happened upon the idea that evolutionary trees might be useful to indicate which taxa are distinctive, and therefore deserve the highest conservation priority. Such taxa, as distinctive as they are, might tend to mislead parsimony by branch attraction.