system of logic vs negate

system of logic is a noun but negate is not a noun.

Word	Noun	Adjective	Verb	Adverb
system of logic	Yes	No	No	No
negate	No	No	Yes	No

system of logic (noun)	negate (noun)
a system of reasoning

system of logic (verb)	negate (verb)
	make ineffective by counterbalancing the effect of
	prove negative; show to be false
	deny the truth of
	be in contradiction with