At times in Earth's history, volcanoes have been more active and large ice sheets have covered the continents. The fact that this is not observed today contradicts uniformitarianism.

Question

Quizplus · Accepted Answer

Uniformitarianism, the principle that the same natural laws and processes that operate in the universe now have always operated in the universe in the past and apply everywhere, does not preclude changes in conditions such as volcanic activity or the presence of ice sheets. It suggests that the processes observed today have been consistent over time, but it allows for variations in intensity and effects, such as periods of increased volcanic activity or glaciation.

At Times in Earth's History, Volcanoes Have Been More Active