William Craig gives a good initial account of “creation” by distinguishing the senses of cause and then saying creation is efficient causality without material causality. But he fumbles the account by placing the action at the beginning of time and seeing modern cosmologies as giving some support to the idea of creation.
I pick on Craig only because the application of the principle he works from leads us to a different conclusion. If creation is efficient causality as prior to material causality as such, the foundation of material being is not matter but choice. Material causality is a second-story reality and not a ground-floor one. True, matter might have a real necessity within a conservation law, but conservation laws are only meaningful in relation to created causes.
A doctrine of creation vindicates the positive element of Berkeley’s thought: the foundation of material things is an act of mind and will. This remains true even for those creation doctrines which (in a denial of the negative aspect of Berkeley’s thought) see this creative act giving rise to a real material substrate, for example, those doctrine that see the creative act as (sometimes) speaking to the created mind by way of the mediation of a material substrate.