Larry is a sensible boy.
He doesn't believe in ghosts, not even poltergeists (they're the mischievous ones who don't frighten you but who can be very annoying).
However, he had started noticing the way things did not always stay where he had put them.
For instance, after cleaning his teeth, he heard something drop on the floor - it was the tube of toothpaste that he'd put back on the shelf.
He was a bit surprised because he didn't think he had left it anywhere near the edge.
Another time a book that he had placed on a bookshelf when he went to answer the phone was on the floor when he came back.
Well, it was hard to believe but he must have left it balanced on the edge.
Then one day his mum asked him to stop leaving his jacket around and to hang it on a hook in the hall.
Being a sensible boy he did so right away.
But five minutes later his mum called out in a loud voice "I thought I told you to hang your coat up!" "I did", he protested.
"Well, why is it on the floor?" she replied crossly.
And when he went back to look, the coat was on the floor as he was already expecting.
But as I keep saying, Larry is a sensible boy and he does not believe that things can move about on their own.
So how did that coat get on the floor when he was pretty sure that he had hung it properly on the hook? Jill (his sister) must be the cause of the problem.
She had overheard his exchange with their mum and had dropped his coat on the floor for a joke.
He told her to stop trying to get him into trouble by playing silly tricks on him.
She denied doing anything of the sort and looked so surprised that Larry thought she might be telling the truth.
The only other explanation was that he had not put his jacket on the hook as carefully as he had thought.
Larry had done science at school and he knew that a good way to find out how things work is to carry out experiments.
He decided to carry one out for himself.
He would put his coat on the same hook in the carefullest possible way and only when his sister was not in the house.
Then he would go away and come back every five minutes for half an hour to see if the coat was still on the hook.
The experiment was a long time starting because Jill kept coming in and out of the hall.
Then the phone rang and he heard her speaking to her friend saying, yes she'd like to come round.
And she went out.
Good, the experiment could start.
When he came back after the first five minutes the coat was still there of course.
And the second time.
And the third and fourth times.
This is getting ridiculous, he thought.
But he must carry on for the full half hour that he had allocated to the experiment with two more inspections.
Of course the coat was still there at the fifth time and at the last one, the sixth.
Larry felt pleased with himself - his experiment had turned out just as he had expected.
No-one except himself had been near the hook and the coat was still there - no ghosts had interfered with it because there aren't any ghosts, QED.
He went into the garden and kicked his ball around.
When he saw Jill coming back down the road with her friend and stopping to sit down in the garden he wasn't bothered because the experiment was over.
Nevertheless he found himself strolling casually back into the hall to sneak another look at his coat on the hook.
Then he felt a tingle in his spine.
His coat was on the floor.
He knew that Jill had been nowhere near it and he still could not believe in ghosts.
But he kept looking for an explanation.
Then the young scientist saw the only logical conclusion.
His experiment had not proved that there are no ghosts.
What it had shown was that ghosts stay away from scientific experiments.
And that, Larry decided, makes it very difficult to prove that they do not exist.