 A sixth argument for the nonconceptual content of perception derives from Kelly (2001b). He argues that the central reason perception must be nonconceptual is that the experience of a property depends on the situation in which it is perceived and depends on the object which it characterizes in a way that demonstrative concepts do not. An example of the first sort of dependency is given by the phenomenon of color constancy. In this case we can see two samples of the same color property illuminated differently (e.g., when looking at a wall that is partially exposed to the sun) and experience both to be of the same color but because of the different illumination we experience them differently (one is better illuminated than the other). The problem is that since the color is the same regardless of the illumination, demonstrative concepts such as that color cannot be sufficient to capture the experiential difference between the differently illuminated samples; though the experiences differ, the contribution of the demonstrative concept that color to the content of the experience is the same, given that the property perceived, that color in both demonstrations, is the same. Demonstrative concepts, Kelly argues, refer to situation independent features of the world (e.g., the actual color of the wall) and thus are not capable of capturing the situation dependence of perceptual content. The argument from the situation dependence of perceptual content has been subject to several criticisms on behalf of the conceptualist. One such criticism (Peacocke 2001b) is that, contrary to Kelly, it seems reasonable that the difference in experience can be captured by concepts regarding the illumination of the different samples (see also Ablondi 2002).