Why Does Time Pass Only Forward?

Imagine you drop your favorite toy. It falls to the floor and stays there. It does not jump back up into your hand. This is because time moves in one direction, like a river flowing downstream.

The universe likes things to get messy. When you play with toys, they get scattered. A clean room becomes a messy room. Scientists call this messiness entropy. Entropy always goes up. This is why we see the past behind us and the future ahead of us.

We remember what happened before because those events made our world more messy. We cannot remember tomorrow yet because it has not made its mess. So, time passes forward simply because the universe keeps getting more disordered.