5. When our thought seeks something for our sense to fasten to [in this concept of unformed matter], and when it says to itself, "It is not an intelligible form, such as life or justice, since it is the material for bodies; and it is not a former perception, for there is nothing in the invisible and unformed which can be seen and felt"--while human thought says such things to itself, it may be attempting either to know by being ignorant or by knowing how not to know.