This weekend the Library of Economics and Liberty has a nice piece on why economics is often called the "dismal science." According to the post, the phrase originated not in a debate over economic growth, as is commonly believed, but in a debate over slavery. John Stuart Mill, one of economics's foundational thinkers, strongly supported emancipation because "economics assumed that people were basically all the same, and thus all entitled to liberty."
It's interesting to note the contrast between the strong morality in John Stuart Mill's economics and the flaccid morality of today's economics, which is restrained by its rejection of any comparison between two persons' outcomes (one exception might be todays' economists' broad support of open borders).
One way this bears itself out is the treatment of animals in modern economics. John Stuart Mill's intellectual forbears and descendants are notable for supporting basic equality for animals. The claim is different from the human slavery case because Mill's criticism of slavery invoked the equality of ability, whereas criticisms of animal husbandry rest more simply on the moral equality of animal suffering and human suffering. Nonetheless, the implication is strikingly similar: that viewing animals as property without any intrinsic value is untenable. Today's economics ignores this simple and just claim. Modern economic analysis regards a dog or a pig no differently from a sofa, with the scant literature on the subject determining their value entirely by the decisions of the consumer. It would be good to see economics reclaim its moral heritage and begin regarding animals' well-being as having a value in its own right, independent of humans'.
(It should go without saying that I do not wish to compare black slaves of the nineteenth century to nonhuman animals, especially given the potentially violent results of such comparisons. What I am saying is that there is a similarity in the desire to draw an arbitrary line of moral consideration, and that economics should reject this.)