What is "masked man fallacy"

alt. A fallacy of inferring that since one knows (or does not know) something by one description, one must know (or not know) it by another, as in "I know who my father is. I do not know who the masked man is. Therefore, my father is not the masked man." n. A fallacy of inferring that since one knows (or does not know) something by one description, one must know (or not know) it by another, as in "I know who my father is. I do not know who the masked man is. Therefore, my father is not the masked man."