A primary aim of cognitive science is the investigation of psychological and neuroscientific generalizations that hold across subjects. Individual differences between people’s minds and brains are pervasive, however, even among subjects considered neurotypical. In this dissertation, I argue that both scientific practice and our philosophical understanding of science must be updated to reflect the presence of such individual differences. The first half of the dissertation proposes and applies a philosophical account of what it takes to explain variation, while the second half identifies several methods in psychology and neuroscience that demand reform in light of existing individual differences
