Abstract
Russell alleged that the version of the cosmological argument he debated with Copleston involved type confusions, but the definitions of plural descriptive functions and the ancestral in Principia Mathematica can be used to reformulate the argument in a type-safe way via a notion of causally self-sufficient classes. Although the argument depends on the assumption that the class of contingent things is not causally self-sufficient, if that assumption is weakened to say only that it may not be so, then a new modalized version emerges which has similarities with recent ontological arguments but weaker and more intuitive assumptions. (Familiarity with Principia notation and conventions is presupposed throughout.)