 In preceding sections, we examined problems facing presentism that come from metaphysical quarters. In particular, we looked at a problem of “cross-temporal relations”  (§4),  and discussed two instances of that general problem, which pose special problems for presentism (§§5–6), before examining a related challenge concerning temporal passage. Now, though there are many worries for presentism that come from metaphysics, perhaps the most serious objection to presentism comes from physics. In particular, the special theory of relativity (“STR”) has been presented as in direct tension with presentism. [See the entry on  being and becoming in modern physics.]