Empty Space
is hardly empty
From a cosmological point of view, intra-galactic space is filled with dark matter and inter-galactic space is filled with dark energy. From a quantum point of view, space is seething with zero point fields and virtual particles popping in and out of existence.
and matter is primarily-
Empty Space
Atoms are almost completely empty space with tiny little electrons bound around tiny little nuclei. The protons and neutrons in the nuclei are themselves mostly empty and electrons are so small their size is below measurable limits.
Sounds to me like they are about the same thing. They are both pretty much empty and both occupied by “fields”. Electromagnetic fields and nuclear fields dominate at the atomic level. Dark energy and dark matter dominate at the cosmological scale. They are placeholders for our ignorance; no one actually understands them. To be sure, fields are hypothesized to exist to avoid action-at-a-distance. Objects then interact with a field with which they are in direct contact, rather than some magical influence from afar. Much more on this on the blog, the paper and the book.