Popularized in the mid-1700s, the doctrine of laissez-faire is one of the first articulated economic theories. It originated with a group known as the Physiocrats, who flourished in France from about 1756 to 1778; led by a physician, they tried to apply scientific principles and methodology to the study of wealth. These "économistes" (as they dubbed themselves) argued that a free market and free economic competition were extremely important to the health of a free society. The government should only intervene in the economy to preserve property, life, and individual freedom; otherwise, the natural, unchanging laws that govern market forces and economic processes—what later British economist Adam Smith, dubbed the "invisible hand"—should be allowed to proceed unhindered.