In his New Theory of Vision, George Berkeley argued that touch is the basis for the spatial sensitivity of the remaining senses. There appear to be counterexamples, that is, intangibles that are spatial: rainbows, the sky, microscopic entities, and holes. A flexible Berkeleian can argue with surprising plausibility that these are actually tangible. However, Berkeley (and his two centuries of followers and adversaries) overlooked how shadows are genuine counterexamples. Echoes of Berkeley's theory of vision can still be heard in contemporary vision research. These echoes are also affected by the fact that shadows are entirely visual.
Keywords: touch, George Berkeley, holes, sky, microscopic