They believed that there were in the beginning no heavenly bodies, air or earth, only water everywhere, over which at first hovered a formless Supreme Being called Pha.
This group of ideas culminated in the Logos of Philo, expressing the world of divine ideas which God first of all creates and which becomes the mediating and formative power between the absolute and transcendent deity and passive formless matter, transmuted thereby into a rational, ordered universe.
Albert and Aquinas agree in declaring that the principle of individuation is to be found in matter, not, however, in matter as a formless substrate but in determinate matter (materia signata), which is explained to mean matter quantitatively determined in certain respects.
He thought that besides proximate matter, or one body as matter of another, there is a primary formless matter beneath all bodies, capable of becoming all in turn, but itself potentially, not actually, substance.
Regarding evil simply as privation, Eckhart does not make it the pivot of his thought, as was afterwards done by Boehme; but his notion of the Godhead as a dark and formless essence is a favourite thesis of theosophy.