Some ideas are so fundamental to physics to science itself that they don't even appear in science itself.

It's like the foundation of a building. You can see the building, doors, windows,

walls, roof, the usual, but you don't see the tons of concrete below the surface, or in the case

of skyscrapers, the giant pillars that they drive hundreds of feet into the ground to support

the structure.

I've shared on this show all sorts of cool physics and astronomy, and sometimes I've shared the guts.

I don't just show you the paintings in a house or the cool architecture or check out that skylight.

Sometimes I bust open the walls and show the electrical wiring and the plumbing.

And sometimes we take a deep dive into the septic system like we did with nine episodes on the meaning of quantum mechanics. But my goal with this show is complete knowledge of time and space.

And if we just stick to what's happening above the ground, we're going to miss a lot.

So today, we need to talk about foundations, about basements, about blocks of concrete.

We need to talk about causality.

Causality is so simple, so obvious, so immediately in your face true that it shouldn't even need to be talked about.

It's simple. Every effect must have a cause, and every cause must come before every effect.

I have to swing a bat before I can hit it with a ball.

You can only feel someone after they touch you.

The sound of two cars crashing only happens after they've hit each other.

I have to eat the slice of cheese before I can taste it.

You can't think a thought that you haven't had yet.

Causality encodes. It enforces our everyday experience of the world. Every interaction among us,

humans, and every interaction among all the particles of the universe obey this simple cause

and effect relationship.

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