PPIG: Philosophy, Psychology, and Informatics Group

Speaker: Gary Hatfield (University of Pennsylvania)

Title: Phenomenally Converging Railway Tracks: A Misperception?

Abstract: Railway tracks appear to converge into the distance. However, observers typically don’t believe that they do converge physically. Is this appearance a misperception? Is the apparent convergence an illusion, like the Mueller-Lyer illusion? With the arrows, one line looks longer than the other, an appearance widely considered to be illusory, yet we are not taken in and so we don’t misperceive in the sense of making a false judgment about the actual length of the lines. One might say that there is phenomenal misperception of line length but no judgmental misperception. Good enough. But I intend to argue that the phenomenally converging train tracks are not a misperception in this phenomenal sense. Construing them as a misperception depends, in my estimation, on a particular task analysis of phenomenal perception: that it aims to present physical scenes in a way that conforms to their mind-independent physical structure (a view found in theorists as disparate as Gibson and Burge). My idea is that the contraction of visual space, as with the tracks, is not a mistake brought about by inadequate information about distance, but rather a phenomenal accommodation of the decreasing information with distance, an accommodation that presents the tracks in a manner which reveals action-guiding information and is ecologically efficient. This conception interacts with notions of what counts as an illusion. Illusion is typically defined as a mismatch between appearance and reality. But not every such mismatch is considered an illusion; and, I argue, not every mismatch is a misperception. I find that what counts as a mismatch or an illusion is dependent on the expectations of the perceiver.