Full Idea
The weak ex nihilo principle says that everything comes from something, and the strong ex nihilo principle says that in everything new, something of the old must endure
Gist of Idea
Weak ex nihilo says it all comes from something; strong version says the old must partly endure
Source
Robert Pasnau (Metaphysical Themes 1274-1671 [2011], 02.5)
Book Reference
Pasnau,Robert: 'Metaphysical Themes 1274-1671' [OUP 2011], p.33