Sherlocks Imaginary John

Sherlock knew that, at a young age, having an imaginary friend was a normal part of the human brain’s development.Sherlock knew that, when a child grows up friendless, it is common to invent a companion to abate loneliness.Sherlock knew these things; but he still refused to tell anyone about John.Sherlock has grown up alone and isolates himself, expressing himself only to his imaginary friend John. But what if John wasn't as imaginary as Sherlock thinks? And could Sherlock ever connect with someone outside his head?