Viewpoint: Yes, the best available and most widely accepted models of Earth's structure once precluded large-scale horizontal motion of continents.

Viewpoint: No, geologic evidence shows that the continents had once been in very different positions, and thus must have moved great distances across Earth's surface over time.

Scientific ideas and theories change through gradual evolution and sudden revolution. Sometimes the systematic exploration of shared principles leads to an expansion and accumulation of knowledge about a subject; other times, competing concepts about the most fundamental hypotheses of a field clash for acceptance. For several decades during the twentieth century, earth scientists wrestled with an idea at the very foundation of their field: had the continents we observe on Earth today been stationary throughout history, or had subterranean forces reshaped...