In esoteric traditions, the existence of a "primordial substance" is recognised and referred to by various names such as "prakriti", or "prima materia". Here we shall call it "primal matter".
Primal matter is what matter is prior to it being observed. When it is looked at, it takes on the appearance of what we call "matter".
The occult orders that I have looked at believe that, at the inception of our universe, primal matter descended from the Divine domain in a spontaneous act of creation, as referred to in the book of Genesis. And, simultaneously, began to seek its return. In traditional religious literature, the domain of the Divine is often referred to as "heaven", and the domain of primal matter as "earth". These two are sometimes pictured as being like the earth and sky in a child's painting. And flowing between the Divine and the primal matter is "Spirit". When Spirit first strikes the primal matter, after the act of creation, primal matter is so captivated by the experience that it immediately begins to seek a means by which it can be intensified. And in order for primal matter to experience more intensely this spiritual presence, it needs to form itself into structures that can focus Spirit upon it.