A noun that describes a person or group that sees all sides of an argument but doesn't have any opinions on it or make any judgements?

I'm looking for a noun that describes a person or group of people that see all sides of an argument, but not take any sides or make any judgements from those sides. They simply acknowledge all sides of the argument and, as an example, if they were a news source, they display that information for the reader to decide their view on. Any ideas?

An impartial observer or dispassionate observer.

Impartial

not partial or biased : treating or affecting all equally

MW

or dispassionate.

not influenced by strong feeling
especially : not affected by personal or emotional involvement

MW