Marcellus believes that the ghost of King Hamlet has been appearing, but Horatio does not believe that could be possible. Marcellus brings Horatio out in hopes that the ghost will appear again that night so Horatio can see it with his own eyes and finally believe what they've been saying.
Why do the first two sentences contain qualifiers (“oddly enough,” “however”)?. Ellison is floating some theories here, an activity he has invited the reader to join.
