Read the passage from Sugar Changed the World.

A fire was lit in a giant iron cauldron, and the certificates of 2,300 Indians were tossed into the flames—the first major act of Satyagraha. "I am not property," the Indians were showing. "I am not your victim," they were demonstrating. "I have the power of my conscience," they were proving. The quiet strength of the Indian community shook the South African government. And by June 1914 it gave in; the Black Act was taken off the books. The Indians had insisted that they were not mere workers but were citizens—and finally the government could not resist.

What evidence do the authors include to support the central idea of this passage?