My 2018 book, The Philosophy of Time and Perceptual Experience, had a chapter on ways in which the perceptual experience of space can be distorted – ways in which we can have mistaken (erroneous) perceptual experiences of things around us in space.
(For convenience, I’ll also call mistaken perceptual experiences ‘perceptual errors’. There is arguably a difference, but its not important here.)
Those mistaken ways and their variety mattered to me. In the book, I argued that the different kinds of perceptual errors had different kinds of bad results for our theories of the actual world. We need experience to separate what is actual from what is merely possible. A theory may be coherent. However, for theories of the actual world, coherence isn’t as important as actual experiences that support them. And mistaken experiences are no good in this supportive role. Mistaken perceptual experiences do not match the actual world and so do not support any theories of the actual world that match them.
So, I was interested in working out ways experience could go wrong and the relevance of that to experience’s role in helping us know about the actual world. In general, I argued: Hallucinations were worse than illusions, illusions worse than what I call anosognosia.
Hallucinations and illusions are well-understood, so I won’t define them here. Their differences can be debatable, but they both share this: they involve the appearance of something that is not the case. Anosognosia is importantly different.
Here is basic definition of anosognosia, with a few notes on it.This definition is off the top of my head; I go into way way more detail in my book; take the book over what I say here where there is conflict. (Also, I’ve discussed the different categories of perceptual error elsewhere on this site, but I do a better job in my book):
Anosognosic experience: An anosognosic experience includes ignorance of the limits of one’s experience and so a mistaken sense that one’s experience is of all that there is.
This kind of error is needed to contrast with (a) accurate experiences of all that there is, (b) illusions and hallucinations (one’s experience is of more than there is) and (c) amodal errors, where there seems to be more than one experiences (however one understands that.
You can get this kind of error merely by having a limited experience – very common – and having no sense that its limitations do not match limits of the world.
Having laid out the importance of experience, error, and the differences between kinds of error, I then argued that whether or not there are experiences which are illusions, hallucinations, or anosognosia can depend on your theory of the world in the first place. You can have a situation where only some theories give you a particularly bad perceptual error; others don’t.
This doesn’t mean that we aren’t committed to a theory with bad errors, even if there are other theories without them. I take it that not all my dreams are, like Little Nemo, visits to other worlds, worlds in which what I dream is exactly like it appears, even if a theory that said they were might mean there is less perceptual error.
My dreams frequently don’t contain the kinds of things I wish to explain as being real, e.g., when I was very young, I dreamt I was a cat attending primary school, a cat who kept dropping my pencil because I couldn’t hold it with my paws. Does that experience need to be real or part of the actual world?
However, as may be obvious in my work, I did think that sometimes a claim that a certain kind of experience was erroneous was only the case given some theories of time. This, again, is a central theme – no, the central theme – of my 2018 book.
This leads to weird visual perception. To get to a proper account of how judging there is error in perceptual experience can be theory-dependent, I realised I had to turn to some non-time examples. So, I looked at one of the more important ones: our perceptual experience of space.
The Perceptual Experience of Space
Despite theoretical confusions that might tempt one to say otherwise (e.g., mistakenly thinking all there is to time is clock time), our experience of time is a fundamental experience; or, another way one might conceive of it, time that we experience is a fundamental part of our overall experience; it is there in our seeing of motion, hearing changes in tone, feeling our weight as we dangle by our arms from a tree.
Like our experience of time, our perceptual experience of space – be it sight, sound, touch – is a fundamental experience – or, another way of saying it, it is a fundamental part of overall experience. We don’t just feel this and that – we feel this there and feel that here. Our shoulder has a pain in it, above the itchy bra-strap, left of our loud caffeine-loaded heartbeat and the taste of gum, and to the right of the wall we knocked it off.
But it also seems as if our perceptual experience of space is radically prone to error. There seem to be lots of frequent and obvious variation in how it is mistaken. Surely this undermines the usefulness of perceptual experience of space? The variation is a neutral and obvious empirical fact.
So, no matter our theories of space or indeed of anything else, we can discount it whenever we like. It is no great problem to ignore the perceptual experience of space if it conflicts with our theories.
OK, but maybe not so fast with the dismissal of such spatial experience. It might be good to slow down and investigate what exactly is happening when we have ‘distorted’ perceptual experiences of space. Perhaps a particular experience’s definition of ‘distorted’ is not so obvious or neutral.
Rare is Not Wrong
The first response to throw away is the rarity of a particular experience. I took it as a truism that rare is not wrong. Merely by being uncommon, a particular experience is not inaccurate. The evaluation of experience’s accuracy is not a matter of consensus, convention, or probability. If the world is the way a rare experience presents it as being, and not the way a common experience does, then that’s enough to make the common experience wrong and the rare experience right.
So, in my 2018, I wondered: under what conditions would a perceptual experience which we would often call distorted (or mistaken or wrong) not be distorted (or mistaken or wrong)? And what can we learn from the possibility of those conditions?
So, to start, I distinguished the typical human experience from the alternatives by the terms ‘typical’ and ‘non-typical’. This was to avoid any possible prejudice and confusion, which ‘normal’ or ‘common’ might cause. Then I defined a particular kind of non-typical visual perception, which I called cubist vision.
Here is a diagram depicting the difference between non-cubist and cubist vision. It depicts accurate visual experience through (A) a typical process of human vision and through (B) a non-typical process of cubist vision:
The non-typical vision is cubist* because, relative to the typical human vision, it is vision from multiple points of view. It is similar to what Cubists depict in their work, e.g., Rivera’s picture below (see also Picasso, Cezanne, and many many others). This vision is also accurate, not mistaken, when what it presents resembles such cubist work.
*I also once called it snail-vision or prehensile-vision, because I conceived of the eyes as being manipulable like a snail’s eyes or a human’s hands. But that goes further than I need to – so don’t worry about it.
In the figure, where A picks out the typical visual process and B picks out the cubist visual process,
- The dotted lines pick out what happens between visual stimulation (at the eyes) and the brain.
- Thought bubbles contain the visual phenomenology (or appearances) – what is visually experienced.
- Orange lines are part of the A process and blue lines are part of the B process.
- All experiences are veridical or accurate.
What is seen through cubist vision is different to what is seen through typical vision. This is the case even though there is the same brain and the same environment. The difference is because of how the visual organs are placed in relation to the environment.
A person with typical vision sees the star and cross-circle in front of one side of the blue wall. The person with Cubist vision sees the hourglass and donut in front of a different side of the blue wall.
Error and the Difference Between Typical and Cubist Vision
Cubist vision is not so different to typical vision. It has a visual phenomenology and it is accurate. The hourglass and donut are in front of those organs, just as they seem to be. And, other than the variable orientation of the visual sense-organs, what processing is part of vision is, in all important ways, the same, e.g., the same brain processes occur in both. The only significant difference is the length of the connection between eye and brain, and this doesn’t matter.
So, a difference between typical and cubist vision is no indicator that cubist vision is wrong. And I use cubist vision (along with other arguments) to help settle the conditions under which visual experience is wrong and pull them apart from the conditions under which visual experience is rare, strange, or merely possible.
It also allowed me to unpack ways vision can go wrong. For example, if I had cubist vision but believed I only had typical vision, I may believe what I see to be orientated to the left and right of my face (or body). Say, for the sake of this discussion, this is a complex perception that includes what I see, my sense of my own body’s location in space, and the spatial relationship between both. However, it is not and so my vision is mistaken. If this is such a perceptual error, then it is a particular kind of perceptual error – anosognosia, a failure to detect that there is more to what I perceive than what there appears to be.
(And, of course, the reverse is also possible. I may believe what I see to be orientated to eyes that have significantly different orientations to my face or body.
This move allowed me to extend the cases of non-typical (not necessarily wrong) examples of perception to cases where a difference in orientation is not due to something between the brain and sense-organ (such as the eye) but due to something else. Importantly, with respect to mirages, I extended it to orientation differences due to something between the sense-organ and the object. I asked again: Would such differences mean a perception is mistaken? And how, again, would it be mistaken?
And once I got there, I went further: I brought in the possible temporal properties of the perceptual process, allowing a difference in orientation due to shifts in the spatial relationship between the brain, the sense-organ and the object over time.
That’s where I describe and use the main elements of my work. It is also where, for some, my proposals get a little weird.
Which is fine. Again, I’m interested in accurate perceptual experience, given the best theories we have about the nature of reality. All my arguments rest on eternalism, the best theory we have about time. If an eternalist theory of perception is a weird theory, so long as it does the best work for perception, it doesn’t trouble me.
Weird is a kind of rare. Again, like rarity,
Weird is not wrong.