The main focus of Enlightenment thinkers in the 18th century was reason and rational thought as the foundation for human progress and understanding. They emphasized the importance of science, individual rights, and skepticism of traditional authority, including the church and monarchy. Thinkers like John Locke, Voltaire, and Jean-Jacques Rousseau advocated for liberty, equality, and the pursuit of happiness. Their ideas contributed to significant political reforms and revolutions, including the American and French Revolutions, and laid the groundwork for modern political philosophy and democratic governance, profoundly influencing contemporary ideas about human rights and governance.