[1]
Direct realists reject representational contents, holding instead that the phenomenology of perception is grounded in what properties one is directly aware of. They face a parallel set of issues with regard to the question of how precise the properties are that one is directly aware of.
[2]
As Tim Williamson noted when some of this material was presented at Oxford, the fuzziness of the borders is vagueness rather than imprecision. Ryan Perkins & Tim Bayne argue against representationism using considerations of vagueness (2013).
[3]
Some of the philosophers who call themselves “representationalists”, for example Michael Tye (2009), have endorsed “object-involving” representational contents. Suppose I am looking at a tomato and having an experience that represents the tomato as being red782. You are looking at an exactly similar tomato in identical circumstances and also having an experience that represents it as having red782. According to Tye, we are having phenomenally different experiences in virtue of looking at different tomatoes. As Burge has noted in an article on direct realism (2005), there are object-involving phenomenal types (of the sort Tye is talking about), but there are also non-object-involving phenomenal types. Representationism as discussed here is concerned with the latter types. I mentioned in footnote 1 that the same issues about precision arise for direct realism—and the same applies to Tye’s view.
[4]
The popular “predictive coding” framework (Clark 2013; Hohwy 2013) is a kind of Bayesian approach that is sometimes thought to provide a revolutionary alternative to the view of perception as constitutively involving veridically conditions. Of course all of vision science involves a background of Bayesian probabilistic processes. And prediction in the visual system is ubiquitous and important. But these approaches do not undermine the veridicality of perception. A recent review of Jakob Hohwy’s 2013 book on predictive coding (Wilkinson 2014) singles out the predictive coding explanation of binocular rivalry as the parade case, claiming that the predictive coding framework “provides a very satisfying account of binocular rivalry.” Clark (2013, pp. 184-185) also emphasizes the supposed explanation of binocular rivalry. Binocular rivalry is a surprising visual phenomenon in which different stimuli are presented at the same time to the two eyes, e.g., a face to one eye and a house to the other. What the subject sees however is an alternation between a face filling the whole visual field, then a house, then a face, etc. It is widely agreed in vision science that the rough outline of the binocular rivalry phenomenon is explained by a combination of reciprocal inhibition and adaptation: the competing interpretations reciprocally inhibit one another, and when one is in the ascendancy, adaptation weakens it until the other takes over. Hohwy and his colleagues more or less concede this (Hohwy et al. 2008) saying that the predictive coding framework explains why we have reciprocal inhibition and adaptation in the first place. But to the extent that this reflects what is good about the predictive coding framework, it is not a revolutionary alternative to standard vision science but rather an evolutionary gloss on it.
[5]
For a direct realist, phenomenal precision is just the precision of the properties we are directly aware of. We can be directly aware of properties with different precisions, for example, crimson, or alternatively red. Similarly we can be directly aware of a 10%-20% contrast property and also a 10%-30% contrast property and the difference constitutes a phenomenal precision difference.
[6]
This argument can be stated in direct realist terms but it would require an analog of the veridical/illusory distinction in direct realist terms. See Block (2010) and footnote 14.
[7]
I used Figure 2 in a talk at Pittsburgh where Boone was in the audience on November 2, 2012.
[8]
G. E. Moore (1903) famously said “... the moment we try to fix our attention upon consciousness and to see what, distinctly, it is, it seems to vanish: it seems as if we had before us a mere emptiness. When we try to introspect the sensation of blue, all we can see is the blue; the other element is as if it were diaphanous ...”
[9]
For an amusing account of the facts surrounding these issues see Ramachandran & Hirstein (1998).
[10]
This effect could be regarded as larger than the result from the Yeshurun and Carrasco paper reported in 5. In that paper, 75% accuracy was achieved by a .20o cued gap as compared with a .22o uncued gap. That difference may be because the 75% accuracy is arbitrary. Or if the difference is real, we could point to the fact that in the Gobell and Carrasco study, the comparison is between an attended square and a square from which attention has been withdrawn, whereas in the Yeshurun and Carrasco study the comparison is between a case in which something is cued and a case in which nothing is cued. Note that there is no need for a mask in this experiment since variations in iconic memory between subjects would be expected to affect equally both the square on the left and on the right.
[11]
As mentioned earlier, this methodology tells us that the two were indiscriminable and it is a further step to conclude that they actually look the same.
[12]
Spatial attention does not require feature-based attention or attention to an object. See Wayne Wu’s book on some of these issues (2014).
[13]
Carrasco (Carrasco et al. 2008, p. 1162) has been interpreted as agreeing with Treue by Stazicker (2011a) and Watzl (forthcoming). Carrasco tells me she did not mean to endorse the Treue view.
[14]
It may be thought that the issue of which percept is veridical is avoided by forms of direct realism that hold that there are no perceptual illusions. For example, Bill Brewer holds that in the Müller-Lyer illusion (so called) in which lines of the same length look to be of different lengths, what one is seeing is a resemblance between the situation in front of one’s eyes and what he calls a paradigm of different lengths. The idea is that that is what equal lines look like when surrounded by opposite–facing arrowheads. And the way equal lines look in that circumstance is like pairs of unequal lines one has seen. On this form of direct realism, the “illusion” to the extent that one can speak of such a thing is in the mistaken inference that the lines in front of one’s eyes are of different lengths. They resemble pairs of lines of unequal lines but one should not conclude that they are unequal.

However, Brewer requires differentiating between cases in which one sees a property instantiated before one’s eyes that is not a resemblance to something unseen and the cases in which one sees a resemblance. In effect, the cases in which one sees a resemblance to something unseen is a pseudo-illusion category that he has to recognize. So the question arises of whether this pseudo-illusion arises in the case of attention or in the case of the lack of it. That is, is one seeing a resemblance to a non-existent thing when one attends or when one does not attend? And this is an unanswerable question for the reasons explored in this section.
[15]
In Block (2010). Actually, I spoke of “indeterminacy” and—mistakenly—of “vagueness” of perception.
[16]
This is oversimple since attention increases sensitivity to high spatial frequencies (Barbot et al. 2012).