"Believer: Ghosts exist. People everywhere in all cultures have believed in them. All those people couldn't be wrong." "Skeptic: If ghosts exist, it's not for that reason. People once believed Earth was flat, too." Source: Moore, B. N. & Parker, R. (2001). Critical thinking. Mountain View, CA: Mayfield Publishing Co. What are the logical flaws here? Are you making any assumptions that might be untrue?           Is it true that "people once believed the Earth was flat?" Is there a case to be made that the earth is flat?