Abstract

The claim that perceptual illusions can motivate the existence of sense-data is both familiar and controversial. My aim is to carve out a subclass of illusions that are up to the task, and a subclass that are not. It follows that when we engage the former we are not simply incorrectly perceiving the world outside ourselves, we are directly perceiving a subjective entity: one’s grip on the external world has been marginalized – not fully lost, but once-removed. However, admitting that various illusions do not give evi¬dence for sense-data considerably limits the power of the argument from illusion (Section 6) and brings out its distinctness from the argument from perceptual relativity (Section 7). To reach these conclusions we will examine the role of ambiguity in perception (Section 3), its connection to illusion (Section 4), and the link reference has to every element of this dis¬course (Sections 2 and 5).