In addition to Adam Smith's legacy, Say's law, Malthus theories of population and Ricardo's iron law of wages became central doctrines of classical economics. The pessimistic nature of these theories led to Carlyle calling economics the dismal science and it provided a basis of criticism of capitalism by its opponents.
This is incorrect. As David Levy and Sandra Peart have shown, the reason Carlyle called economics "the dismal science" is that the free-market economists of his time, who dominated the economics profession, strongly opposed slavery.
HT to Lawrence Samuels.
UPDATE: The mistake on Wikipedia has been corrected. I'm guessing it was by one of the readers of this post.
UPATE 2: They're back. As commenter Robinson points out below, the mistake in Wikipedia is back.