natural philosophy vs identical

natural philosophy is a noun but identical is not a noun.

Word	Noun	Adjective	Verb	Adverb
natural philosophy	Yes	No	No	No
identical	No	Yes	No	No

natural philosophy (noun)	identical (noun)
the science of matter and energy and their interactions

natural philosophy (adjective)	identical (adjective)
	(of twins) derived from a single egg or ovum
	coinciding exactly when superimposed
	having properties with uniform values along all axes
	exactly alike; incapable of being perceived as different
	being the exact same one; not any other: