ELI5: Explain Like I'm 5

Uniformitarianism (science)

Uniformitarianism is a scientific idea that says the same natural laws and processes we see happening today, like erosion and earthquakes, have been happening since the Earth was formed and have shaped the Earth into what it is today. For example, the Grand Canyon in the United States was formed by the Colorado River carving out the rock over millions of years. That's uniformitarianism in action.