 As we will see in §3.6, the constructive empiricist might naturally express skepticism, in the case of unaided veridical perception, about the existence of anything like image-like phenomena. Kusch (2015) points out one reason for skepticism: the phenomena in question exhibit fewer of the invariant relations—“unlike, say, rainbows, visual experience cannot be photographed” (177)—that would allow us to characterize the phenomena as public, verifiable ones capable of empirical study.