/summa/FP/FPVIII/FP_Q66:
We must next consider the work of distinction; first, the ordering of creation towards distinction; secondly, the distinction itself. Under the first head there are four points of inquiry:
(1) Whether formlessness of created matter preceded in time its formation?
(2) Whether the matter of all corporeal things is the same?
(3) Whether the empyrean heaven was created contemporaneously with formless matter?
(4) Whether time was created simultaneously with it?