Perceptual Evidence

How should we explain why perceptual experience provides us with evidence? Dogmatism and evidential internalism treat conscious mental states as explanatorily basic and posits a particular rule for justification, namely, that if it perceptually seems that p, then one has prima facie justification for p (Pollock 1974, Feldman and Conee 1985, Pryor 2000, Huemer 2007, among others). The knowledge-first view treats knowledge as explanatorily basic and analyzes justification in terms of a deficiency of knowledge (McDowell 1982, Williamson 2000, Millar 2008, Nagel 2013, Byrne 2014 among others). Reliabilism treats the reliability of the perceptual or cognitive system as explanatorily basic and analyzes evidence and justification as a product of this reliable system—be it in virtue of a reliable indicator or a reliable process (Goldman 1979, 1986, Lyons 2009 among others). By contrast, capacity views treat capacities as explanatorily basic and analyze evidence, justification, and knowledge as a product of the capacities employed. Among capacity views there is a distinction to be drawn between normative capacity views, on which mental capacities are understood as virtues or in other normative ways (Sosa 1991, 2006, 2007, Greco 2001, 2010, Bergmann 2006), and capacity views that forego normative terms (Burge 2003, Graham 2011, Schellenberg 2013, 2014). So on the first cluster of views, conscious mental states are explanatorily basic, on the second cluster knowledge, on the third reliability, and on the fourth capacities. These options are neither exclusive nor exhaustive. One might think that more than one of these four elements are explanatorily basic, or one might think that what is explanatorily basic is something else entirely.

What evidence does perceptual experience provide us with? To answer this question lets first distinguish between phenomenal evidence and factive evidence. We can understand phenomenal evidence as determined by how our environment sensorily seems to us when we are experiencing. We can understand factive perceptual 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.Standard internalist views have it that we have the very same phenomenal evidence when we perceive and when we hallucinate. Standard knowledge-first views have it that when we perceive, we have factive evidence; when we hallucinate we have no evidence provided directly through experience: When we hallucinate we have only introspective evidence. Capacity views can go either way on the question of whether we have the very same or different evidence when we perceive or when we hallucinate. One option is to argue that when we perceive we have phenomenal and factive evidence; when we hallucinate, we have only phenomenal evidence. 

For dogmatism and evidential internalism, see Pollock 1974, Feldman and Conee 1985, Pryor 2000, Huemer 2007, among others. For knowledge-first views, see McDowell 1982, Williamson 2000, Millar 2008, Nagel 2013, Byrne 2014 among others. For reliabilism, see Goldman 1979, 1986, Lyons 2009 among others. For normative capacity views, see Sosa 1991, 2006, 2007, Greco 2001, 2010, Bergmann 2006. For non-normative capacity views, see Burge 2003, Graham 2011, Schellenberg 2013.