 As Millikan (2013a) and others have pointed out, there are representations that cannot be caused by their contents, such as TOMORROW. No tomorrow has ever caused a thought about tomorrow. However, TOMORROW is not a sensory-perceptual representation and so this is not an objection to Neander’s proposal per se. As with other modest theories, however, the challenge is explaining how to link this modest theory for some mental contents to a more comprehensive theory that accounts for all of the contents of all of our concepts (see also  section 4.4).