ELI5: Explain Like I'm 5

Big Book (thought experiment)

Okay, imagine you have a really big book in front of you. This book is special because it has every single thing that has ever happened in it. You can look up anything and everything that has ever happened, from the very beginning of time to the present day.

Now, imagine that you are able to magically change things in the book. You can make things happen differently than how they actually happened.

For example, let's say you want to change the outcome of a big sports game. You find the page in the book that has the details of the game, and you change the score so that your favorite team wins.

But here's the tricky part: if you change one thing, it might have a ripple effect and change other things as well. Changing the score of a game might seem like a small thing, but it could cause all sorts of other things to happen differently. Maybe the team that lost the game would get really upset and start a fight, causing chaos in the stadium. Or maybe the winning team would become overconfident and start losing a bunch of games later on.

So even though it might be tempting to try to change things in the big book, it's important to remember that every little thing is connected to other things in ways we might not even realize.