There are no rules in science

[instrumental music] A couple of thousand years ago, a guy called Thales predicted a solar eclipse.

He calculated that the moon would occlude the sun, turning day to night, and sure enough, the moon occluded the sun, turning day to night.

Now, that's interesting.

So interesting that a bunch of battling warriors stopped fighting and called off the war they'd been waging for six years, or so the story goes.

Let's give Thales the benefit of the doubt and suppose that he not only predicted that an eclipse would happen, you know, sometime soon.

Let's suppose that he predicted when the eclipse would happen, because that's what's interesting about what he did.

He didn't just say, "There's the sun and there's the moon, and they move all over the place, and at some point they're gonna be in the same place." He predicted when they would be in the same place in the sky and what that might look like to battling warriors here on Earth.

This broke the rules.

By the thinking of the day, the gods who governed the seas and the skies were chaotic.

You might be able to appease them by sacrificing a lamb, but you certainly couldn't anticipate their vagaries.

Thales' prediction of the eclipse proved this rule wrong.

Now we have a new rule.

Scientific theories must make predictions.

It's a good rule.

If your theory makes a prediction, a prediction that's novel, a prediction that's precise, then we have a way to test it.

If the eclipse happens when you say it's gonna happen, then we'll be more inclined to believe that your theory has something to tell us about the universe.