 Without reducing creaturely possibilities to God’s actual perfections (as idealists do with extension), Spinoza presents an alternative grounding thesis and a challenge. Let every possibility be grounded in God via actual exemplification, even if this requires expanding the divine nature beyond its traditional boundaries. For those unwilling to follow Spinoza on this expansion, Spinoza’s challenge is for proponents of nearby alternatives to provide a non-metaphorical explanation of how God grounds certain basic possibilities without actually and directly exemplifying them. Until such an account is given, Spinoza’s biting conclusion offers an unmet challenge: “But by what divine power could [extension or any property not exemplified by God] be created? They are completely ignorant of that. And this shows that they do not understand what they themselves say” (Ip15s). At the very least, Spinoza’s challenge highlights how his modal metaphysics extends beyond the topic of necessitarianism and continues to invite wider investigation.