4 On the notion of “phenomenal precision”
Any argument against Representationism has an initial appeal to me. Ned Block’s is at the cutting edge of empirical research and subtle in its argumentation. But I suspect that its crown jewel, “phenomenal precision”, has a few shady facets.
“Phenomenal precision”, Block admits, is in need of clarification. The guiding example for Block (this collection) is where “[t]he experience of a color as red is less phenomenologically [sic] precise than the experience of a color as crimson”. Here I want to focus a bit more on how we may understand p–precision, what it might and what it ought not to mean in the context of Block’s work.
4.1 Lower bounds of p–precision
The way I estimated phenomenal precision in my reconstruction was as follows: consider, first, how a controlled stimulus appears under ideal conditions (e.g., rested, attending, etc.) as some phenomenal feature. For example, how blue34 in a standardized patch looks as blue, how an olfactory sample (e.g., a CAS 93686-30-7, Ext. Sup. I, 1000ppm) smells as Ylang-Ylang, how 480 mc/sec/cm² feels as pain, and so on. Then, see how much variance in the stimulus is not mirrored in the appearance as F: for example, the pain caused by 480 mc/sec/cm² is not reliably discernible from one caused by 640 mc/sec/cm²; instead both feel as pain near maximal intensity. Because I cannot differentiate between 480 mc/sec/cm² and 640 mc/sec/cm² by the feeling they cause, my pain feeling’s p–precision must at least cover these values. This provides us with a lower bound for that specific feeling of pain. More broadly, for any phenomenal character—i.e., experiencing something as F (e.g., a color as red, a tone as C♯', a patch as having 28% contrast)—, the lower bound of its p–precision is that range of cases one cannot distinguish by experiencing as F under ideal conditions. That’s what the PPP suggests (see p. here).
This allows us to make sense of the red vs. crimson example: crimson is a very specific phenomenal feel, which allows for very little variation while remaining crimson. Red, on the other hand, allows variation along the whole spectrum, from coral and vermillion, via crimson and oxblood, to maroon. So any experience of a color as crimson is also likely to be[17] an experience of a color as red—but so is an experience of a color as vermillion. And the range of cases that may cause an experience of red compared to those that may cause an experience of crimson under ideal condition is larger. So experiencing as crimson is more p–precise than experiencing as red.
4.2 A need for solely generic phenomenology?
I think that triviality or contradiction looms if we do not add another constraint to be satisfied: In order for p–precision to be non-trivial, there must be the possibility of experiencing a color as red, but not as crimson42, vermillion11, coral19, oxblood81, etc. That is, there must be a way of experiencing something as a higher–order property F, without experiencing it as any first-order property F1, F2, … subsumable under F. Rick Grush (2007) has called this Generic Phenomenology—but I am speaking more specifically of solely generic phenomenology (SGP), i.e., generic phenomenology without an accompanying and subsumable concretum.[18]
Why ought we commit ourselves to SGP? Because otherwise the p–precision of an experience is either contradictory, generally minimal, or generally maximal, which trivializes the notion. Why?
Look at the color in figure 2. What is the p–precision of this color impression?
Figure 2: A stimulus of color 660000 or 16-86-94-42 CMYK.
You probably experience this color as red, but also as having a specific shade of red—for which you might lack a name, but let us baptize it cayenne66. It is natural to assume that this holds for all color impressions, e.g., that whenever you experience a color as red, you also experience it as a most specific shade. In this case, there is no SGP—just a generic phenomenology accompanied by concrete and “subsumable” phenomenology. What might be the p–precision of your color impression in this scenario?
You might think that this color experience has two p–precision values:[19] The first value is for being experienced as red, and the second for being experienced as cayenne66. But this seems contradictory: why should one and the same experience of a color have two p–precision values, but only one for r–precision? And for that matter, why not three values for p–precision? You likely experience the color not only as cayenne66 and as red, but also as a color? Why not four, then, if you experience it as a visual experience? Or five, if you experience it as something? Or even six, if you experience it as phenomenal? The more options we consider, the less sense it makes to speak of the p–precision of a percept at all. But this is needed for Block’s argument, where changes in p–precision are lower than the respective changes in r–precision. This hardly works if we allow multiple values. So we should assign experiences only one p–precision value.
If we have to assign this color experience only one p–precision value, we could either choose the lowest or the highest feature. Either option looks arbitrary, which is already bad. But it gets worse if we reject SGP: If we chose the lowest feature (cayenne66) and if there must always be a lowest feature, then all experiences of a type have the same level of p–precision and this value must be stable. If we chose the higher feature (red), then there is no reason to stop there: we certainly experience the color as a color, as a visual impression, or as something. But the character of being something applies to (almost) every experience. So all experiences would again be equally and fixedly p–precise. Both cases seem to trivialize the notion of p–precision, because it always stays the same. So p–precision seems either contradictory or static and trivial without SGP.
We ought to accept SGP in order to allow for variance in p–precision: we can experience some color as red, but not as e.g., cayenne66 and so on. More generally, we can experience something only as a higher–order property F without experiencing it as any lower order property F1, F2, … subsumable under F. Then, different experiences allow for different degrees of indeterminacy and therefore different degrees of p–precision.
However, SGP has been introduced to argue against Block: According to Grush (2007), if we accept the possibility of generic phenomenology, then we could see something as some letter without seeing it as a specific letter (A, B, ...). This affects one’s interpretation of the Sperling experiment: Sperling (1960) showed participants a grid of letters, which they identified as letters from the short impression they got. Yet they could not identify and recount all of them. But when they were cued to repeat a specific line by a tone after the stimulus disappeared, they were able to recount the letters in that line without fault. Block (2007) has used this and other experiments to argue that phenomenality goes beyond what we can cognitively access: people have a full phenomenal impression, but cannot access all the information available in their experience. Their experience is concrete, but their introspective access is shaky. SGP proponents counter that one can have generic experiences while all the underlying concrete information is subconscious. So before the cue, subjects experience concretely according to Block, but generically according to proponents of SGP. Allowing SGP thus blocks Block.
Additionally, generic phenomenology seems to be closely associated with symbolic or rule-based[20] representation. Imagistic representation, on the other hand, does not allow for such indeterminacy, because images exploit the isomorphisms between concreta. I can write “The cat is on the mat” without saying anything about whether the cat is a Siamese or a Maine Coon, or whether the mat is filled with feathers or made of bamboo, or whether the cat reclines, sits, or scratches on the mat. The sentence can represent the fact without resembling a cat or a mat at all. However, if I want to represent the fact that the cat is on the mat in an image, I have to depict something concrete: a specific cat at some position on a mat doing something. The common understanding of images is that they are concrete and as such determined in all their lowest-order properties. Analogue representations more generally exploit concreteness in order to represent by isomorphism.[21]
Introspectively, our phenomenal experiences resemble images. If phenomenal experience represents imagistically, then there cannot be SGP—and p–precision seems dangerously close to being trivial; if phenomenal experience is non-imagistic, then we can allow for SGP and render p–precision non-trivial—but this is in tension with some of Block’s other work and our introspective evidence.
Maybe a fixed p–precision value need not be bad for Block’s argument: if the p–precision of percepts is fixed, but r–precision varies, then there is a phenomenal feature that is not grounded in a representational feature. Thus, GR is false. However, Representationist have an easy reply: GR does not claim that all changes in representational features must be mirrored in phenomenal features; representational features only need to account for phenomenal features. If p–precision is fixed, then it might be grounded in there being r–precision at all. For Block, accepting SGP might be a good option here—but not elsewhere.
4.3 Introspective imprecision?
There might be a way to reject SGP, but still account for our belief that we can experience a color as red without experiencing it as crimson. Maybe experiencing as F without experiencing as any subsumable F does not apply to phenomenal experiences, but to our access to them. That is, maybe there is introspective rather than phenomenal precision.[22] This might go along the lines of Block’s interpretation of the Sperling experiment: we experience very specific shapes, but introspectively, we are only able to label them as letters, not as A, B, etc. So maybe the phenomenal aspects of our experience have fixed precision because it is never solely generic; but our introspective judgements are not fixed in precision because we can introspect some experience solely generically. That is, we may judge an experience of cayenne66 to be red although we actually experience it as cayenne66. If perception can be more or less imprecise, why can’t “internal perception”?[23]
The notion of introspective imprecision, however, is not easily applied to the example of the patches in Carrasco et al. (2004): if we introspect on their appearance, then we judge them not as imprecise, but as of precisely the same contrast.
But maybe the imprecision of introspective access is not itself introspectively available: Our introspective access might be limited, such that all we can tell is that the patch we attend to is like the patch we don’t attend to in some respect. However, our general introspective bias—that we think ourselves as authoritative about our own minds leads us to overrate what introspection offers: what we introspect as being more or less alike is judged as being strictly alike. This bias towards seeing ourselves as introspectively authoritative independent of whether we introspected successfully or not might lead to a wide variety of false beliefs about phenomenality.
The upshot would be that introspective imprecision is compatible with Block’s distinction between access- and phenomenal consciousness. But introspective imprecision leaves it open whether SGP holds or not. It seems that we cannot decide based on introspection whether the character of our percepts or our introspective access to them is imprecise. We would need some other access to our phenomenality in order to settle the issue; but at this moment in time, nothing comes to mind that offers decisive evidence.[24]
Block’s writing suggests that he rejects introspective imprecision in this article (although he ought to accept it when defending the distinction between access- and phenomenal consciousness). If we reject it with him, how can we save the idea of percepts being more or less p–precise?
4.4 Limitation on characters?
The idea that parts of perceptual wholes can be more or less imprecise seems to stand in tension with the idea that all appearance-features can turn up anywhere in the phenomenal field: any appearance of contrast may appear in the fovea or periphery or where I attend or don’t attend, etc. This had the odd consequence in my reconstruction that all phenomenal parts have the same degree of p–precision. How might we avoid this?
We could assume that the range of characters in the focus of attention and in the fovea is most fine-grained. Imagine being able to experience 100 shades of crimson in the attended fovea, but only 20 shades of crimson in the unattended periphery. This is reasonable for contrasts as our sensitivity to it declines with eccentricity (Banks et al. 1991).
But this suggests that our experience is less continuous in the periphery. Instead, it is stepwise. This fits to the idea of precision having to do with bandwidths: in the attended fovea, we experience with a higher bit-rate than in the unattended periphery. It is like seeing a picture in 24- instead of 6-bit color depth (see figure 3).[25]
Figure 3: A 24-bit picture compared to a 6-bit picture. Shifting attention between the two while focusing on the + ought to provide some experience of indistinguishable character if experience in the periphery is more coarse grained.
But the coarse-grained character of experience outside of attention is not introspectable: if a light slowly changes color in our periphery, it does not look like it is doing so stepwise. It looks smooth and continuous. So somehow this idea only makes sense if we add the idea of introspective imprecision—and thereby inherit its problems.
So it is open how we should marry the idea of variances in phenomenal precision of a specific character with Block’s overall view of conscious experience. Some more elucidation would be highly appreciated.