Charles Robert Darwin and Alfred Russel Wallace: their dispute over the units of selection.

Charles Darwin and Alfred Russel Wallace independently discovered the mechanism of natural selection for evolutionary change. However, they viewed the working of selection differently. For Darwin, selection was always focused on the benefit for the individual. For Wallace, selection was as much something of benefit for the group as for the individual. This difference is traced to their different background political-economic views, with Darwin in favor of Adam Smith's view of society and Wallace following Robert Owen in being a socialist.