On my last afternoon in Rome I was staring at the menu of a cafe not far from the Coloseum when I heard someone say, in English, 'I don't believe it!' I turned round and looked into the face of my friend, Vanessa with whom I had shared the post of Writing Fellow at the London College of Fashion a few years ago.
This was a real coincidence, but not one which I would easily get away with including in a novel. The last manuscript I sent to my publisher contained a scene which hinged upon a much less remarkable coincidence but it came back with a note from the editor to the effect that this particular episode was a bit hard to believe. I had no alternative but to change the plot slightly to accomodate my editor's scruples
Despite my editor's misgivings it's a fact that I have experienced several extraordinary coincidences in my life. For example when my wife and I were planning our wedding party thirty years ago we really wanted to include the friend who had first introduced us but we'd lost touch with him a couple of years earlier. We tried all sorts of ways to discover where he was living but gave up in the end. Then, on the afternoon preceeding the party, I was travelling to my parents' house on the other side of London when I walked right into him in the middle of Waterloo train station. It was as if I had called the meeting into being by sheer will power.
Now I am not suggesting that there was anything paranormal about either of these two meetings. On the contrary, all I'm saying is that unlikely coincidences do happen; but you can't put them in novels without people saying, 'Oh that's very convenient!'
Clearly realism is not the same thing as verisimilitude. Fiction has to be sufficiently life-like to convince the reader that it's true. But it can't be exactly like life because life contains too many elements which are simply unbelievable.