“One source of misunderstanding is that many of the commentators have been economists who have looked at the Moral Sentiments simply in order to find some relevance for The Wealth of Nations. This gave rise to the so-called Adam Smith problem, a supposed inconsistency between the psychological assumptions of the two books. Another source of error has been a failure to note whether a particular passage was written for the first or for the sixth edition.”

Source: The Death of Economics (1994), Chapter 10, Economics Revisited, p. 212

The Impartial Spectator: Adam Smith's Moral Philosophy (2007), Ch. 1: Two Versions

Robert Fogel (1993) " Economic Growth, Population Theory, And Physiology: The Bearing Of Long-Term Processes On The Making Of Economic Policy http://www.nobelprize.org/nobel_prizes/economic-sciences/laureates/1993/fogel-lecture.pdf." Nobel lecture.

Source: Tractatus Logico-Philosophicus

Conversation on Epictetus and Montaigne
Context: The source of the errors of these two sects, is in not having known that the state of man at the present time differs from that of his creation; so that the one, remarking some traces of his first greatness and being ignorant of his corruption, has treated nature as sound and without need of redemption, which leads him to the height of pride; whilst the other, feeling the present wretchedness and being ignorant of the original dignity, treats nature as necessarily infirm and irreparable, which precipitates it into despair of arriving at real good, and thence into extreme laxity.

Source: 1920s, Prejudices, Third Series (1922), Ch. 3 "Footnote on Criticism", pp. 85-104
Context: Truth, indeed, is something that is believed in completely only by persons who have never tried personally to pursue it to its fastness and grab it by the tail. It is the adoration of second-rate men — men who always receive it as second-hand. Pedagogues believe in immutable truths and spend their lives trying to determine them and propagate them; the intellectual progress of man consists largely of a concerted effort to block and destroy their enterprise. Nine times out of ten, in the arts as in life, there is actually no truth to be discovered; there is only error to be exposed. In whole departments of human inquiry it seems to me quite unlikely that the truth ever will be discovered. Nevertheless, the rubber-stamp thinking of the world always makes the assumption that the exposure of an error is identical with the discovery of truth — that error and truth are simply opposites. They are nothing of the sort. What the world turns to, when it has been cured of one error, is usually simply another error, and maybe one worse than the first one. This is the whole history of the intellect in brief. The average man of today does not believe in precisely the same imbecilities that the Greek of the Fourth Century before Christ believed in, but the things that he does believe in are often quite as idiotic.
Perhaps this statement is a bit too sweeping. There is, year by year, a gradual accumulation of what may be called, provisionally, truths — there is a slow accretion of ideas that somehow manage to meet all practicable human tests, and so survive. But even so, it is risky to call them absolute truths. All that one may safely say of them is that no one, as yet, has demonstrated that they are errors. Soon or late, if experience teaches us anything, they are likely to succumb too. The profoundest truths of the Middle Ages are now laughed at by schoolboys. The profoundest truths of democracy will be laughed at, a few centuries hence, even by school-teachers.

Fragment No. 104; on Edmund Burke's Reflections on the Revolution in France (1790).
Blüthenstaub (1798)

1990s and later, "The Institutional Structure of Production" (1992)

Source: The Unfinished Autobiography (1951), Chapter 6