Adam Smith Quotes about Progress

On the road from the City of Skepticism, I had to pass through the Valley of Ambiguity.
Adam Smith (1978). “Powers of Mind”
Adam Smith (1843). “An Inquiry Into the Nature and Causes of the Wealth of Nations With a Life of the Author: Also a View of the Doctrine of Smith, Compared with that of the French Economists, with a Method of Facilitating the Study of His Works, from the French of M. Jariner”, p.142