 If propositions are complex (structured) entities with constituents, then they depend for their existence upon the existence of their propositional constituents. The way that such entities ontologically depend upon constituents is analogous to the way that sets depend upon their members. Consider, for example, {x}, x’s singleton set. {x} depends upon x for its existence. Typically, this is cashed out as follows: necessarily, {x} exists only if x exists; and, it’s not the case that x exists only if {x} exists. Similarly, we say: necessarily, some proposition P exists only if its (propositional) constituent c exist; and, it’s not the case that c exists only if P exists. [See the entry on  ontological dependence.]