 Simply because some cases of cognitive penetration are not cases of perceptual learning, however, it does not follow that no cases of cognitive penetration are cases of perceptual learning. Jerry Fodor distinguishes between synchronic penetration and diachronic penetration, where only the latter involves “experience and training” (1984: 39). The case of Jack and Jill is a case of synchronic penetration, one where the penetration does not involve experience and training. However, at least some cases of perceptual learning might more plausibly fit into the category of diachronic penetration. (For more on the relationship between perceptual learning and cognitive penetration, see  section 3.2)