For me, the answer to the question, 'Are ghosts real?', is neatly answered by the following quote by Lafcadio Hearn:
The impossible is much more closely related to reality than the greater part of what we designate true and ordinary. The impossible isn't perhaps the naked truth, but I believe that it is often the truth, undoubtedly masked and veiled, but eternal. He who claims that he does not believe in ghosts lies in his own heart.
It should therefore come as no surprise to know that, to me the answer to the question, 'Are ghosts real?', is a resounding,
'Yes, ghosts are most definitely real'.
Lets look at facts that no-one can dispute.
If this does not answer the question, are ghosts real, then what about the circumstantial evidence.
For example, the account the witness gave of the Roman soldier ghosts in York was not believed by some experts because from understanding at the time, it was thought that it was inaccurate. Only after later evidence came to light was it realised that the description of the soldiers was probably perfectly correct.
What of the ghost of the war poet, Wilfred Owen who appeared to his brother moments before he was killed on 4th November 1918 near Ors, France, just days before the First World War ended. His brother, who knew at that moment that Wilfred was dead, said of the encounter, 'He did not speak, only smiled his most gentle smile'.
And how does one explain the countless thousands of nameless dying men and women who see their dead relatives just before they 'pass over'. Relatives who the witness is often unaware are not still, 'in the flesh'.
Either these are ghosts, real phantoms or we have to find some other rational explanation for the phenomena .