One of the main arguments used to dispute the theory of plate tectonics before it gained wide acceptance was the lack of a plausible mechanism to drive plate motion.

While the idea of continents moving was intriguing, scientists struggled to explain *how* they could move across vast distances.

Here are some specific arguments:

* Gravity was insufficient: Early theories suggested that continents "drifted" due to gravity pulling them towards the equator. However, this force was simply not strong enough to move continents over such long distances.

* No driving force was identified: Without a clear explanation for what was driving the plates, many scientists doubted the theory.

* Lack of direct evidence: While there was geological evidence supporting continental drift, it was indirect. There was no direct observation of plates moving, and the process of plate movement was too slow to be observed directly at the time.

It wasn't until the 1960s that the theory of sea-floor spreading provided a compelling explanation for plate movement. This theory, backed by evidence of magnetic striping on the ocean floor, explained how new crust was generated at mid-ocean ridges, pushing older crust away and driving the plates.

With the discovery of this mechanism and other evidence, the theory of plate tectonics gained widespread acceptance and became the foundational framework for understanding Earth's geology.