A Sound of Thunder

A science fiction interpretation of the butterfly effect

Many moons ago, when I decided to join a local amateur dramatics society, I was given a part in a play. I said to the director that I was pleased to have been asked to take on a small part. He replied that he was glad I described it as small rather than minor. “There’s no such thing as a minor part”, he said. “All parts are equally important.” This article has nothing to do with amdram, but it does involve considering the effects of small changes — which are rarely minor ones. Enjoy!

One of my favourite stories, this one by Ray Bradbury looks at the possible consequences of making a small, apparently insignificant, change in the past. Indeed, some people attribute the origin of the term 'the butterfly effect' -- in which a small change results in a disproportionately large outcome -- to this story¹.

Now, I realise that we don't have time travel, but I still think this story makes for an interesting starting point for discussion. An obvious application, for instance, would be the accuracy of a machine that administers medication. A small change in the program controlling the dosage, like moving the decimal point one place to the left or right, could prove fatal.

A less dramatic example would be the work I was commissioned to do some years ago by a company. I was asked to construct a spreadsheet that would keep track of their costs and profits, but with a lot more features than that brief description would suggest.

Because the whole thing was already very complex, the company told me not to worry about pence, and to round amounts up or down to the nearest pound.

I thought, and told them, that this was a mistake because the rounded figures would grow further and further away from the actual figures over time. They wouldn't listen.

What I did, though, was to design the spreadsheet in such a way that only the display showed the rounded figures. Behind the scenes, all the calculations were based on the real figures rather than the rounded ones.

Fortunately, when, a couple of months later, they said they did want the real figures after all, it took me just a few minutes to change the display accordingly.

On another financial matter, a member of my team came to me looking very nervous one day. I asked him what was wrong, and he told me he'd made a tiny error in a formula. Consequently, far from having a surplus of £20,000, we had a deficit. That was another example of a small change that was not a minor one.

But it's not all about money. Bradbury's story posits changes in language and even politics, in a richly entertaining way.

You can find the story in this collection (Amazon associate link).

For other articles in this series, please refer to the index.

1. It’s more likely to be a scientific paper about chaos theory. Here’s a video about it: