Somewhere along the way, we silently began to assume that empiricism was inseparable from the claim that the highest cognitive power in human beings was a sense power. We forgot or ignored the difference between saying that a.) all the objects we know are sensible and b.) all objects are given in the mode of sensation. The truth of a.) does not require the truth of b.)
Metaphysics, as it has been understood until very recently, involves the claim to know things that cannot be sensed. Such a science is compatible with claim a.) above, since we can judge that sensory beings are by nature derivative and secondary- and we cannot call the primary thing an “object” of our knowledge without shifting the word “object” to have a very different meaning. Empirical metaphysics (the doctrine of Aristotle and St. Thomas) does not claim to apprehend the sensory and the non sensory as two different objects which it then divides into two sciences; it claims to form diverse judgments about empirical things- one which considers the empirical as it is in itself, another which considers the empirical in relation to some other which is always known with negation. Again, “the empirical” and the “other” are not a set of homogeneous relations like left and right or up and down or father and son (with such relations there is no impediment to apprehending either of the relatives before the other), rather, the relation is between something apprehended and its negation (with these relations it is impossible to apprehend one of the relatives before the other).
The difficulty we have with understanding empirical metaphysics is tied up with a mistake we make about relatives, sc. thinking that they must be epistemically homogeneous, that is, that there is no impediment to knowing either one first.
Just Thomism 