"We have in MOND a formula that has had repeated predictive successes. Many of these have been true a priori predictions, like the absolute nature of the Tully-Fisher relation, the large mass discrepancies evinced by low surface brightness galaxies, and the velocity dispersions of many individual dwarf spheroidal galaxies like Cluster 2. I don't see how this can be an accident. But what we lack is an underlying theoretical basis for the observed MONDian phenomenology: Why does this happen?"