A while ago,  when I was in the Oxfam bookshop I saw a book I didn’t buy. To be accurate, I actually saw thousands of books I didn’t buy, but there was one particular book. I picked it up, looked at it, asked myself if I had a good reason for adding it to my existing mountain of books, and reluctantly put it back. (Under my new system I’m trying to buy books only when I’m sure I’m going to read them within the next few months. It’s a forlorn hope but I have to tell Julia something.)

After I dropped Julia off yesterday morning I wondered about visiting the bookshop while I was on that side of town. However, I had a list of  errands to do and decided to make a start on that. As for the book, it will either be there when I go back, or it won’t, and that was when the phrase Schrödinger’s Books passed through my mind.

As everyone knows Schrodinger’s  Cat is an illustration of  what he saw as the problem of the Copenhagen interpretation of quantum mechanics applied to everyday objects.

What? You don’t? You need to stay in more and read Wikipedia. Then, having read Wikipedia, you have to understand it.

It problem features a sealed box containing a cat, a source of radioactivity and a flask of poison. If radioactivity is released it is detected by the Geiger counter which releases the poison and kills the cat. If no radioactivity is released, the cat lives. Because the box is sealed the cat might either be alive or dead, or both.

Alternatively, like me, you can use cut and paste and get by with a vague understanding, secure in the knowledge that most of your readers are similarly vague. To be honest, when I first saw the words Schrödinger’s Cat, I thought it was the sequel to Flaubert’s Parrot. It would make quite a trilogy with Lady Chatterley’s Plover.

I’d have to take issue with “everyday objects” , as I don’t tend to have a Geiger counter, a source of radioactivity and a flask of poison lying around the house. However, it does make more sense than Einstein’s  assertion that a barrel of unstable gunpowder can exist in both exploded and unexploded states. Having, in my re-enactment days, had an Explosives License, I can’t appreciate the subtlety of Einstein’s position. With gunpowder I’ve always thought of it as an either/or situation. Either you have a roof, or you don’t have a roof. There isn’t much room for compromise.

Anyway, back to books. You see a book in a shop and don’t buy it. When you walk out of the shop you can no longer see it and  don’t know whether it is there or not, so it’s both there and not there.

My version of the problem works better with secondhand books. In a shop selling new books it’s more likely they will have a copy when you want one. In a second hand bookshop there’s probably a bigger chance of the book being gone when you go back. Unless it’s Fifty Shades of Grey. There are plenty of them about.

It also works better with books than cats: in the absence of food and water, there is, I feel, a fundamental flaw in the assumption that the cat is alive beyond a certain point.

This is probably a good way of defining a scientist – a man who can reveal the mysteries of the Universe but can’t run a cattery.