Metaphysics is the branch of philosophy that treats of first principles, includes ontology and cosmology, and is intimately connected with epistemology. It is the search for the underlying theoretical principles of a subject or field of inquiry, brought to light by the publication of the same name by Aristotle in the 4th century BCE. It deals with first principles, the relation of universals to particulars, and the teleological doctrine of causation.

The RS2 inquiry also includes fields of what is known as "alternate science"--stuff that happens, and does not appear to fit current scientific belief. By using the principles of the Reciprocal System and RS2, much of the "alternative science" realm is easily understood, since the basic premises are far more clear.