 A first step in resolving this question is recognizing that crossmodal illusions are not mere accidents. Instead, they are intelligible as the results of adaptive perceptual strategies. In ordinary circumstances, crossmodal processes serve to reduce or resolve apparent conflicts in information drawn from several senses. In doing so, they tend to make perception more reliable overall. Thus, crossmodal illusions differ from synaesthesia. Synaesthesia is just a kind of accident. It results from mere quirks of processing, and it always involves illusion (or else is accidentally veridical). Crossmodal recalibrations, in contrast, are best understood as attempts “to maintain a perceptual experience consonant with a unitary event” (Welch and Warren 1980, 638).