No one defines journalism as "what a journalist does," so there is no cycle. If you ask Google to define "journalism," you get, "the activity or profession of

No one defines journalism as "what a journalist does," so there is no cycle. If you ask Google to define "journalism," you get, "the activity or profession of writing for newspapers, magazines, or news websites or preparing news to be broadcast." See, no use of the word "journalist" in that definition, so no circle.