philosophical system vs doctrine

philosophical system and doctrine both are nouns.

Word	Noun	Adjective	Verb	Adverb
philosophical system	Yes	No	No	No
doctrine	Yes	No	No	No

As nouns, philosophical system and doctrine are synonyms defined as:

philosophical system and doctrine: a belief (or system of beliefs) accepted as authoritative by some group or school

Other synonyms of philosophical system include ism, philosophy, school of thought.

philosophical system (noun)	doctrine (noun)
a belief (or system of beliefs) accepted as authoritative by some group or school	a belief (or system of beliefs) accepted as authoritative by some group or school