Multimodal Mental Imagery and Perceptual Justification

There has been a lot of discussion about how the cognitive penetrability of perception may or may not have important implications for understanding perceptual justification. The aim of this chapter is to argue that a different set of findings in perceptual psychology poses an even more serious challenge to the very idea of perceptual justification. These findings are about the importance of perceptual processing that is not driven by corresponding sensory stimulation in the relevant sense modality (such as amodal completion and multimodal completion). These findings show that everyday perception is in fact a mixture of sensory-stimulation-driven perceptual processing and perceptual processing that is not driven by corresponding sensory stimulation in the relevant sense modality and that we have strong reasons to doubt the epistemic pedigree of the latter process. The implication of this is not that we should become skeptics or deny the possibility of perceptual justification. It is, rather, that the only way in which we can understand when and whether a perceptual state justifies beliefs is by paying close attention to empirical facts about the reliability of perceptual processing that is not driven by corresponding sensory stimulation in the relevant sense modality. In this sense (a very narrow sense) epistemology needs to be naturalized.