What were the main subjects on which Wallace and Darwin disagreed?
While Wallace and Darwin agreed on most of the basic premises of the subjects they studied, Wallace was never afraid to disagree with his older colleague when he saw fit to do so. There are several main issues on which they differed (for discussion see the writings cited): (1) the extent to which natural selection could explain the development of humankind’s higher moral and intellectual faculties (S146, S165, S724; Smith 1972, Kottler 1974, Koch-Weser 1977, Schwartz 1984, Malinchak 1987, Shermer 1991, Smith 1992 & 2004, Vincenzo Bizzo 1992); (2) the extent to which sexual selection (especially female choice) could explain sexual dimorphism and related matters (S139, S186, S272, S724; Kottler 1980 & 1985, Aiken 1982, Borgia 1986, Cronin 1991, Caro 2005); (3) the explanation for the existence of arctic plants in the Southern Hemisphere, and on mountaintops in the tropics (S721 & S724); (4) the validity of Darwin’s theory of pangenesis (S532, S729; Marchant 1916); (5) the legitimacy of t
