In Defense of Phacts
The phenomenology (or conscious experience) of perception would be much easier to study scientifically if the only relevant facts were -- as Pete Mandik suggests (if I understand him right) -- facts about, on the one hand, external objects and the sensory organs, and on the other hand, our judgments about external objects and sensory organs. Facts of the first sort are objectively measurable and facts of the second sort are directly reportable or expressible (at least on a sufficiently thin notion of "judgment").
On such a view, when I stare at a visual illusion and say "Line A looks longer to me than Line B", I can be wrong about the length of the lines, but I can't be wrong about how the lines look to me. There is no thing, distinct from the lines in the world, the state of my eyes (about which I'm making no claims), and that very judgment itself for me to be wrong about.
The view is appealing, but I don't think it can be right. For one thing, consider non-obvious visual illusions. The following figure is sometimes presented as an instance of the "horizontal-vertical" illusion, according to which vertical lines look longer. There may also be other illusions in it. (Do the lines look like each bisects the other exactly, or does one of the segments look longer?)
One might be wrong about the actual lengths of the lines on the screen. One might be wrong about how people in general would judge the lines or whether there are consistent errors how we'd reach for such a figure. One might be wrong about the impression such a figure would make on one's retina. But can't one also feel uncertainty about -- and thus presumably go wrong about (or is the uncertainty merely foolish?) -- something else, too: How the figure looks to you right now, whether one line really does look longer to you now than the other? And doesn't a different sort of fact make claims of the last sort true than makes the other claims true?
If I judge that I am experiencing pain, there's a feeling of pain and there's a judgment about it. The pain isn't just the judgment. Nor is the feeling just some fact about external tissue damage, since I might be unconscious or under anaesthesia and so feel no pain.
Suppose I'm convinced that I'm a brain in a vat. I have no eyes, no sensory organs at all, and there are no objects around me -- or so I think. I judge that I'm having a sensory experience of redness right now. That can't be a judgment about external things or about sensory organs, for in my view there are no such things. Am I judging that I'm judging there to be a red patch out there? That can't be right either. I don't judge that there's a red patch in my environment. Am I judging that I'm having an experience that's like the experience that would normally be caused by looking at something red? I don't see why I have to be judging that, either -- I might be skeptical about "normal causes" -- but let's say, for the sake of argument, that that is what the judgment comes down to. There's that word "experience" in there. It seems I'm making a specifically phenomenal claim -- a "phactual" claim, if you will -- a claim that is made true or false by facts about my experience, not facts about the outside world or my sense organs or about some judgment.