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.
Originally published in 1742, Observations upon Liberal Education is a significant contribution to the Scottish Enlightenment and the moral-sense school of Scottish philosophy.
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.