How did John Stuart Mill criticize William Whewell’s view of moral intuitionism?

Intuitionism Read more from
Chapter Nineteenth Century Philosophy

Mill’s criticism of Whewell’s moral intuitionism was that it implied that morality could not progress because necessary truths are always true. Mill further claimed that Whewell’s necessary moral truths would preserve the status quo, and he charged Whewell with conservatively supporting slavery, marriage without women’s consent, and cruelty to animals. What Mill missed, however, was that, as with Fundamental Ideas in science, Whewell held that we may not know all of the relevant rules of morality. Thus, discovering these rules allowed for moral progress.