George Turnbull belongs with a group of early Scottish Enlightenment thinkers, including Francis Hutcheson, who found their native Calvinism too repressive. They sought to relocate religion within a context of reason and science and to establish a tolerant and humane ethic upon values rooted in classical ideals.
The Principles of Moral and Christian Philosophy presents the first masterpiece of Scottish Common Sense philosophy. This two-volume treatise is important for its wide range of insights about the nature of the human mind, the foundations of morals, and the relationship between morality and religion.
Originally published in 1742, Observations upon Liberal Education is a significant contribution to the Scottish Enlightenment and the moral-sense school of Scottish philosophy.