I think the temptation is very strong to notice the distinction between the elemental nature of raw sensory inputs and the cognitive significance they are the bearers of. And this is so, and is useful to do, precisely to the extent that the cognitive significance will vary depending on context and background knowledge, such as light levels, perspective, etc. because those serve as dynamically updated calibrations of cognitive significance. But these calibrations become transparent with use, so that we see, hear and feel vividly and directly in three dimensions because we have learned that that is the cognitive significance of what we see, hear, feel and navigate through. Subjective experience comes cooked and raw in the same dish. It then takes an analytic effort of abstraction of a painter’s eye to notice that it takes an elliptical shape on a focal plane to induce the visual experience of a round coin on a tabletop. Thus ambiguities, ambivalences and confusions abound about what constitutes the contents of subjective experience.
I’m reminded of an experiment I read about quite some time ago in a very old Scientific American I think, in which (IIRC) psychology subjects were fitted with goggles containing prisms that flipped their visual fields upside down. They wore them for upwards of a month during all waking hours. When they first put them on, they could barely walk at all without collapsing in a heap because of the severe navigational difficulties. After some time, the visual motor circuits in their brains adapted, and some were even able to re-learn how to ride a bike with the goggles on. After they could navigate their world more or less normally, they were asked whether at anytime their visual field ever “flipped over” so that things started looking “right side up” again. No, there was no change, things looked the same as when they first put the goggles on. So then things still looked “upside down”? After a while, the subjects started insisting that the question made no sense, and they didn’t know how to answer it. Nothing changed about their visual fields, they just got used to it and could successfully navigate in it; the effect became transparent.
(Until they took the goggles off after the experiment ended. And then they were again seriously disoriented for a time, though they recovered quickly.)
What should we take for P(X|X) then?
And then what can I put you down for the probability that Bayes’ Theorem is actually false? (I mean the theorem itself, not any particular deployment of it in an argument.)