Experience and Evidence

I argue that perceptual experience provides us with both phenomenal and factive evidence. To a first approximation, we can understand phenomenal evidence as determined by how our environment sensorily seems to us when we are experien-cing. To a first approximation, we can understand factive evidence as necessarily determined by the environment to which we are perceptually related such that the evidence is guaranteed to be an accurate guide to the environment. I argue that the rational source of both phenomenal and factive evidence lies in employing percep-tual capacities that we have in virtue of being perceivers. In showing that both kinds of evidence have the same rational source, I provide a unified account of perceptual evidence and its rational source in perceptual experience. What evidence does perceptual experience provide us with? Why heed the testimony of our senses? To motivate these questions, consider a perceiver and a hallucinator. Percy, the perceiver, accurately perceives a white cup on a desk. Hallie, the hallucinator, suffers a subjectively indistinguishable hallucination as of a white cup on a desk; that is, it seems to her that there is a white cup where in fact there is none. What evidence do Percy and Hallie have for believing that there is a white cup on a desk? I will argue that Hallie has some evidence for her belief, but that Percy has more evidence than Hallie. While standard internalist views have it that Hallie has as much evidence as Percy (e.g. Feldman and Conee 1985), standard externalist views of evidence have it that Hallie has only introspective evidence, but no evidence provided directly through experience (e.g. Williamson 2000).1 In contrast to both approaches, I will argue that perceptual experience provides us with both phenomenal and factive evidence and that both kinds of evidence have the same rational source. To a first approximation, we can understand phenomenal evidence as deter-mined by how our environment sensorily seems to us when we are 1 Conee and Feldman (2008) are open to there being differences in evidence derived from beliefs in the case described. It should be noted that ‘introspective evidence ’ is not Williamson’s term. I will clarify it shortly