 Nowhere does Spencer’s ethics and sociology entwine more palpably than in his Lamarckism, though how much Spencer borrowed from Lamarck as opposed to Darwin is contested. However, Peter J. Bowler has lately argued that both Spencer and Darwin believed that the inheritance of acquired characteristics and natural selection together drove evolution. For Bowler, it is no less mistaken to view Spencer as owing everything to Lamarck as it is to see him as owing very little to Lamarck.[8] Bowler’s assessment is supported by Spencer’s claims in two late essays from 1886 and 1893 entitled “The Factors of Organic Evolution” and “The Inadequacy of ‘Natural Selection.’”[9]  The earlier essay alleges that evolution by natural selection declines in significance compared to use-inheritance as human mental and moral capacities develop. The latter gradually replaces the former as the mechanism of evolutionary change. “Factors of Organic Evolution” succinctly weaves together use-inheritance, associationist psychology, moral intuitionism and utility. Actions producing pleasure or pain tend to cause mental associations between types of actions and pleasures or pains. Sentiments of approval and disapproval also complement these associations. We tend naturally to approve pleasure-producing actions and disapprove pain-producing ones. Because of use-inheritance, these feelings of approval and disapproval intensify into deep-seated moral instincts of approval and disapproval, which gradually become refined moral intuitions.