 Anti-reductionists quickly came to stress the more radical form of multiple realizability mentioned in  section 1.1  above, in a token system over times. As far back as the late 1970s, Ned Block (1978) insisted that the narrowing of psychological kinds required to render them identifiable with specific physical (i.e., neural) kinds due to the more radical type of multiple realizability would render psychology incapable of capturing most all generalizations across realizers. Ronald Endicott (1993) gives Block’s point empirical backing by noting detailed facts about plasticity in individual human brains. The capacity for distinct neural structures and processes to subserve a given psychological function owing to trauma, damage, changing task demands, development, and other factors is extensive. These facts count further against any proposed reduction of, or identities between psychological and physical kinds. Horgan (1993) clearly appeals to this radical sense of multiple realizability when he writes: