What is the purpose of caesars ghost in act 4 ? give examples in the play

There is some debate as to what the ghost actually represents. Although the ghost is in the form of Caesar, it is obvious that he is some sort of manifestation of Brutus's inner struggle. The ghost identifies himself as as “thy evil spirit”. This could mean that Brutus is imagining the spirit because of Brutus's misdeeds or it is pehaps an evil spirit come to haunt him. I think it is the former. Note the quote says "thy" meaning the spirit belongs to him alone. Brutus is a man of deep reflection and his guilt over Caesar's death is almost palpable.