 Astell’s own view about the causation of sensation involves an account of a “sensible congruity” between features of external bodies and powers of the soul that are employed in sensations. For discussions of her account, as well as arguments about whether its roots are in Descartes, Malebranche, or Norris, see Acworth (1979, 174, 178), Taylor (2001, 511–2), Broad (2002a, 109), and O’Neill (2007).