In Asa H categories (concepts, classifiers, case vectors) change continually (R. Jones, Trans. Kansas Acad. Sci., vol. 108, No. 3/4, pg 169, 2005). Some record patterns in space, some record patterns in time.
In typical knowledge-based AI systems (like, for example, CYC) ontologies are (relatively) fixed.
If process philosophy is correct such change is fundamental (Process Metaphysics, N. Rescher, SUNY press, 1996).
If the block universe view of relativity is correct a static ontology is possible.