Category Archives: Space

On the Visual Experience of ‘Cubist’ Vision (Follow-up to my 2018 book, Philosophy of Time & Perceptual Experience)

Summary: Weird needn’t be wrong; common needn’t be right.

As I argued in my 2018, there is a difference between: common, easily-understood, and accurate perceptual experiences; erroneous perceptual experiences; and unusual, hard-to-understand, perceptual experiences. For vision, I argue the latter are what I call (in my 2018) forms of cubist vision. Here, I go into more detail about what that difference is. In short, normal or typical is not identical to accurate and abnormal or nontypical is not identical to incorrect.

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.

Some notes

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 ‘seems’ there placed beside ‘experiences’).

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 particular experiences 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 kind of 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, who visits other worlds – that is, not all my dreams are visits to worlds in which what I dream is exactly like it appears, the things in that world, and this is the case even if a theory that say they are might mean there is less perceptual error (and that’s an empirically good thing).

Little Nemo (Windsor McCay, 1905)

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, it is the central theme – of my 2018 book.

This leads to holding some weird visual perception to be perception that is one of or a combination of a) accurate experience, b) not erroneous experience, c) experience not as erroneous as one’s intuitive theories might require, and d) experience that is not erroneous in the way such theories might offer. To develop 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; time that we experience is a fundamental part of our overall experience. As many philosophers of time will state early in their books, it is there in such things as our seeing motion, hearing changes in tone, feeling our changing weight as we clamber up a tree.

Like our experience of time, our perceptual experience of space – be it sight, sound, touch – is a fundamental experience; space that we experience is a fundamental part of our 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, 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. Perhaps our understanding of some experience as being an example of a distortion depends on something we cannot safely assume.

Rare is Not Wrong

Can the rarity of a particular experience mean it is distorted. No. I took it as a truism that rare is not wrong. Merely by being uncommon, a particular experience is not inaccurate; Superman’s supervision is not super because it is like everyone else’s. 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) but merely rare? And what can we learn from the possibility of those conditions?

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.

Cubist Vision

A particular kind of 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.

Diego Rivera, 1915, Portrait of Ramón Gómez de la Serna, 109.6 × 90.2 cm. Latin American Art Museum of Buenos Aires (From Wikimedia)

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:

Typical vision (A) and ‘Cubist’ vision (B)

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

However strange the physiological setup, or the experience in comparison to typical vision, Cubist vision is not so fundamentally 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. A difference arising from that between typical and cubist vision is no indicator that cubist vision is wrong.

So, I used 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). However, because my vision is cubist, it could be far more complex how what I see relates to my body. What I see (through my non-typical cubist vision) is not to the left and right of my face or body; it may be partly beneath my feet, three hills over, and above my head.

In that case, if it seems to be of the relatively simple location to the left and right, my vision is mistaken. It it is a perceptual error, then it may be 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.

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 this idea 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 might 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 too. And again, like rarity,

Weird is not wrong.


Seeing What is in Front of You (Follow-up to my 2018 book, Philosophy of Time & Perceptual Experience)

Note 1: This post is a follow-up to the chapters in my 2018 book about visual experiences of spatially distant things, things that are at some depth in one’s visual experience.  

Note 2: All illustrations are by me. This is why they are not very good.

It is common to talk about the direction of vision, visual direction, or line of sight. It is common to talk generally about where things are located visually and to talk about a direction in vision. It seems right to say that things seem to be located in a particular visual way to the seeing subject. In addition, some things can be said to be visually off to the side or straight in front of the seeing subject.

It is also common to talk about how things can seem to be in front of you visually, or off to the side, yet not be. The visual appearance, its visual location, can be distorted or mistaken. Presumably, this is because how things appear is different to how things actually are.

However, I have problems with deciding what actual or real direction should be used to evaluate this visual appearance. So far as I’ve looked, I can only find bad reasons to hold that a visual appearance of direction is inaccurate.

That, for many, will be odd. Perhaps I’ve not looked enough. So, let me tell you about how I got here: when working out what the standard or reality for visual direction is, there seems to be nothing that will do. Except one thing – but, for that thing, visual appearance is always right.

Which is strange.

Accuracy-Conditions of the Visual Appearance of Spatial Direction 

When I stand outside on a clear night with a full moon, the full moon will seem to be a certain distance and in a certain direction from me. This is a particularly visual experience: I (at least seem to) see the moon; I don’t (at least seem to) hear it, smell it, or touch it. One might then ask: is the appearance of the moon’s direction and distance accurate?

I don’t like my answer but I don’t know what to do about it. My answer is: except in one possible special way, it is never inaccurate; it is always accurate.

The possible special way is this: if the appearance of the moon’s direction and distance is of it as absolute, then it is not accurate. I assume that apparent direction and distance is highly unlikely to correspond to an actual spatially absolute direction and distance. I do not think that there is absolute direction and distance. Furthermore, if there is an absolute direction and distance, then it would be a matter of chance that appearances correspond to it.

However, I also think that this isn’t clearly how we see the direction and distance of things. If we do, then we can say that this is an erroneous experience of the absoluteness of these spatial properties. For now, whether we have it or not, I’ll put that particular possible experience aside.

This leaves the question I’m interested in: under what conditions is the visual appearance of distance and direction accurate? I am interested in this question because, so far as I can tell, the answer seems to be one of the following:

(a) Visual appearance of direction is inaccurate when it fails to correspond to a relative direction in space.

(b) Visual appearance of direction is neither accurate or inaccurate because there is no fact of the matter about direction. ‘Direction’ is arbitrary.

(c) Visual appearance of (spatial) direction is always accurate because the definition or grounding of direction comes from the appearances, and nowhere else.

For those who want to say that the direction in which something seems is mistaken, (a)  seems best. As there is no absolute direction in space, any attempt to define direction is relative. As with distance or speed, no spatial entity is privileged with respect to spatial direction. It is relative to some points or things that anything is ‘far away’ or ‘moving fast’. It is also relative to some points or things that anything is ‘in front of’, ‘behind’, ‘above’, ‘below’, ‘to the left of’, and so on.

So, the appearances can be inaccurate with respect to relative direction. Yet, which relative direction? Determining that is problematic.

In general, appearances can be used to measure something. Appearances can play an epistemological role, where a theory of the world is evaluated by how closely it corresponds to appearances. In that case, appearance is somewhat like a measuring device, such as a metre stick. If we treat appearances that way here, then (c) is to be preferred: one evaluates the direction of something with respect to visual appearances.

However, here, we are asking about the appearances – about the accuracy of the measuring device itself. Ideally, one does not pick the thing being judged to evaluate it. That makes the accuracy trivial, like measuring a metre stick with itself.

So, what do we do? First, maybe we must bite the bullet here and use appearances, i.e., (c). Whether we like it or not, there is no better way of judging actual visual direction. But many may think otherwise: surely the other options can do something here. Either it is (b), there is a relative visual direction independent of appearances or it is (a), there is some absolute visual direction independent of appearances.

Honestly, I think it’s a toss-up between (b) and (c), not between (b) and (a).

What weighs the odds in favour of one or the other is whether you want to treat appearances seriously. If you are happy to throw them out (e.g., you hold that appearances never define or ground anything), then go for (b). If you are happy to have them play a very serious epistemological role, being the measure of accuracy (and thus, as Wittgenstein notes, unmeasurable for accuracy itself), go for (c).

To sort between these, note that (b) doesn’t provide a direction to evaluate visual appearances against. Instead, it is the position that there is no fact of the matter about a direction. The visual appearance is mistaken insofar as it seems to favour one direction over another. If you say that something seems to be in front of you, or to the side, your mistake is to hold that this could ever be something non-arbitrary – any kind of fact – one way or the other.

So, I think it can be (b) or (c), and I prefer (c). However, I can say little to dissuade someone convinced by the arbitrariness demanded by (b).

However, to a lot of readers, I bet my suggestion that only (b) or (c) are available is obviously wrong . One should take (a) — judgement by relative direction — as the most serious option here.

Consider mirages.


Image by Brahan Milla on Unsplash.

Surely the very definition of mirages requires accuracy with respect to a relative direction.

Mirages, as commonly described, are visual experiences where there seems to be something at a particular location in space which is not at that particular location in space. In the most obvious examples, the variation of appearance and reality is typically described as being visually inverted: that what visually seems to be facing one way is actually facing another.

For example, I see, in an otherwise empty desert, in a small region of the sky, hanging above the horizon in front of me, a street scene — one inverted so that the street occupants’ heads lie below their feet. This is clearly not how they are: they are not walking upside down in the sky. This is an inaccurate visual appearance.

That is a fairly straightforward way of describing the mirage. I imagine it would be risible for many to suggest otherwise. I’m going to suggest otherwise.

The reason I’m going to do that is that what is going on with mirages is more complicated than that it ‘appears upside down and is not upside down’. Once the complications are included, I’m not sure that it’s right to say that things are not how they seem visually. I think that it’s better to say: things are how they visually seem but they do not match expectations of how I might interact with them beyond seeing them. Yet these latter expectations are based on my ignorance of how what I see and what I can touch may interact. This is a multi-sensory error, or an error of multisensory integration, but not of my visual experience itself. (I say more about this elsewhere.)

Some examples of mirages:

Visual Illusion/Hallucination

(For more on this section, see my 2018.)

If I believe in elves that can be seen (i.e., not invisible elves), then I do not hold that the visual appearance of elves is necessarily either an illusion or an hallucination. If I don’t believe in the moon, then I hold that the visual appearance of the moon is necessarily either an illusion (the ‘moon’ is really something else with merely apparent properties that make it seem to be a moon) or an hallucination (there is nothing there at all).

What you believe is real partly determines your beliefs that how things seem is how things are, i.e., the accuracy of experience.

When some experience is an illusion or hallucination, it is in error in some way. As I’ve argued in an earlier post, how it is in error depends (at least in part) on how things appear (a phenomenological condition) and how things are really (a metaphysical condition). What one holds about the latter condition (at least) is theory-dependent. Thus, that there is an error — and what kind — is also theory-dependent.

The error can be different according to different theories even if: (a) everyone agrees as to what is really going on; they need only disagree about what appears to be going on; (b) everyone agrees as to what seems to be going on; they need only disagree about what is really going on.

From this, I think that what is erroneous can depend on what one holds to be real about the senses themselves — and the properties we ascribe to them.

Turning this to errors in the direction of gaze (or visual direction), I think that there are three factors to consider:

  • The definition of the direction of gaze
  • The possibility of experiential error of direction which is neither illusion nor hallucination (what I call in lots of places anosognosia, like in my 2018).
  • The possibility of any experiential error of direction at all

All of these help explain my reasoning for taking (c) seriously: that appearances themselves ground or determine the accuracy of visual direction.

First, as argued elsewhere on the site, I don’t presume the universality of illusory counterparts. Just because something can be apparent doesn’t mean that it can actually be illusory. In the widest set of possible worlds, yes – it’s possible that what’s apparent is merely illusory — but it is an open question with respect to the actual world. Just as it is an open question with respect to the actual world whether we are dreaming.

Second, I think that the greater share of claims to error of direction are discrepancies between

(i) The apparent direction of something and

(ii) Its direction relative to a Earth-derived geometric system idealised as a sphere

However, I think that there is no particular reason to evaluate the accuracy of (i) by (ii). If one is to evaluate the apparent direction by anything, it should be

(iii) A direction relative the path along which light travels from the source to the eye

However, (i) is always accurate when evaluated with respect to (iii) light. By the standard of the path of light itself, it is straight in front of you. This is the case if you choose the path of light from the source to your eye, the very thing that allows you to see the source. If you choose that path, then the source is straight in front of you and even orientated as it appears to be; that apparent direction and orientation is not mistaken.

That is, if something appears to be straight in front of you in mirages, loomings, or other strange visual phenomena, this is not, strictly speaking, erroneous.

(You might choose some other path of light to evaluate it, and judge it wrong. Fine — but why? One path of light is as good as another. If you are arbitrarily doing so, then the error here is at best in the absoluteness of apparent direction and orientation (and distance — but I’m ignoring that in this post)).

I think that will sound very wrong to many readers. However, I think, when it comes to considering the alternatives — the body, the world, the head etc. etc. — light is still the better option. All other options lead to cases that are intuitively not error. This option leads to cases of veridicality that are intuitively error. Since these cases are also cases of perceptually apparent veridicality (simply by being perceptually apparent) then we have a clash between (a) appearances of veridicality and (b) intuitions of error. In such a clash, where neither side is incoherent, I pick (a) every time.

Let’s look at some alternative ways of picking out the correct direction to judge experienced direction.

Where The Eyes Are

My eyes lie a certain distance apart from each other. They can face different directions.

Visual direction and the eye

My eyes are not exactly in the same spatial location.  Not only are they not in the same spatial location, they do not always face in the same direction. One is much weaker and slightly squinted; when I am tired, it points a little inwards toward my nose.


  1. Each of my eyes is In a different place.
  2. At least sometimes, each of my eyes points in different directions. [Note 1]

‘1’ assumes eyes occupy a location in this space (this seems uncontroversial, and I’ll assume it). Further, that each can occupy a different location — again, uncontroversial and I’ll assume it. ‘2’ holds that my eye is pointing in a particular direction. But this is not as clear as ‘1’. It looks like a right thing to say. But: what gives an eye that direction?

There are three possible answers:

A. An eye has an intrinsic direction.

It has a direction whatever else we define as having direction. If an eye is floating in an otherwise empty universe, it still points or faces in some way such that we can say: there is one whole heap of nothing in front of the eye and there is another whole heap of nothing behind the eye.

An eye’s direction of this kind is like the direction of an arrow or a signpost. There is a part of it that lies forward of the eye — analogous to the head of an arrow — and a part that lies back in the way — like the tail of an arrow. [Note 2]

B. An eye has an extrinsic direction.

Its direction is because of something else. It needs something else to say where it is pointing. If an eye is floating in an otherwise empty universe, it can’t be said to have anything lying in front or behind of it.

It is not like an arrow. It is like a line. We say what is at the front because of something else — something else which is like an arrow — and that something else gives it its direction. Draw an arrow and a straight line segment, and put the line segment in relation to the arrow in such a way that part of it is nearer the arrowtail than the ‘head, and part of it is nearer the arrowhead than the ‘tail. If asked ‘where is the segment’s front and back’, my bet is you’ll find it natural to have the front part near the arrowhead, the back part near the arrowtail. [Draw it. You’ll see what I mean].

C. Eyes have no direction, neither intrinsic nor extrinsic*

*I am not sure what to do with that.

If ‘A’ and ‘B’ are right, then we can then also define spatial directions relative to the eyes. If an eye has a direction, we can talk about what lies along that direction, what lies to the left and right of that direction, what lies above and below that direction.

We will move on to the idea that ‘A’ is correct next, and how it applies to defining the visual direction.

But if ‘B’ is correct, then something else defines the eye’s direction. So, what defines that direction?

Defining ‘In Front of the Eye’

What makes one thing, e.g., an apple I’m looking at, in front of the eye while making something else, e.g., the neural processing resulting from stimulation of the eye, behind the eye?

Here are some options: the earth (or some bigger thing, even); the body; the head; the eye-brain system; a specific set of neurons; the ‘self’; a straight line running through the eye. Let’s take each in turn.

D. The Earth/The Earth’s Orbit/The Solar System/The Heliosphere/The Galaxy/The -[insert large embedding spatial entity here]

I can’t make sense of the idea that ‘in front’ for my eye is relative to the earth or any other larger body — to which, for all intents and purposes, we are at rest and in which we are located or embedded. Instead of going through all cases (orbit, heliosphere, etc.), let’s just take the Earth.

‘Directions’ on earth are typically defined in terms of latitude/longitude and North/South/East/West. Let’s ignore for the sake of argument the conventionality of these terms; for example, if we didn’t ignore it, I think we could as much define directions by the rolling of the Earth on its axis about the sun: say, descent-wise (in the direction in which the Earth turns toward the sun) and ascent-wise (the direction in which the Earth turns away from the sun.

To say that directions on the Earth define ‘in front for my eyes’ is to say that something in front of my eye because it is either North/South, etc., of my eye. This means that, no matter how I turn my eyes or head, or body, something remains in front of my eye so long as it is the same relative to the directions defined by the Earth.

I take it that this is just flat-out wrong. But I also think that most other directions, though commonly closer matches to the eye’s direction, e.g., the body, head, etc., are equally as problematic. They have the same general problem: what we call ‘in front of’ for the eye can vary from whatever we might call any direction as defined by them.

E. The Body

The world, the body, and visual direction

Say I define ‘in front of my body’ as the direction shared by (a) the direction in which I walk and (b) my knees move (walking ‘backward’, my knees move in the opposite direction to which I walk). I can turn my head away from that direction.

Now, what is in front of my body is then not in front of my eyes. Also, this definition of the body’s direction seems quite forced to me (but I’ll put that aside for now).

F. The Head

Say I define ‘in front of my head’ as the side closest to the majority of sense-organs (eyes, tongue, nose, ears (just)). I can twist my eyes to the left without turning my head; what is in front of my head is not then in front of my eyes.

G. The Eye-Brain(or Eye-[Specific set of Neurons]) 

One idea might be this: the eye and something to do with the brain (the whole brain, or a particular set of neurons/neural processes) define the direction on which to judge something as being ‘in front’ and ‘behind’. To the question above: ‘What defines neural processes as being  behind the eye?’, the answer is trivial: the direction is defined by the processes being behind the eye. As it were, they are the tail of the direction-defining arrow. In that answer, we might treat it as an unanalysable given that they so lie behind. There is a kind of intrinsic, basic, fundamental direction that the eye-brain system has, such that what is in front of and behind can be derived from it. And then from that, we can define what is in front of the eye, or even that the eye is at the front of the system.

So what picks out the direction? How about this: the eye+brain system has a line from the back to the front of it which can be defined as straight. But what is the ‘front-back’ here? The eyes are in front, the rest of the brain behind it.

Here is a gross counter-example I hope you never have to participate in: I can technically move one eye — say, my left — such that it faces into the connected brain (some already have had it happen as far as looking down the cheek). Now stretch the left eye so that it not only faces into the brain but passes through or over it — so that its facing out from the brain again in the opposite opposite to the right eye. If all of this was happening in the head, I would now have my left eye looking out through the hair at the back of my head.

Now, I have one eye facing backwards according to the other eye. What is ‘in front’ of each eye? An eye-brain system gives two different answers, one for each eye.

However, it does not do so independent of an understanding of the answer independent of thoughts about the brain. It takes it from their already determined direction. And that’s good — because I can’t see any good reason to suppose that either the left or right dominates here as determining eye-brain direction. Here, I’d say the eye-brain system faces in two different directions, with very different things ‘in front’ of it. And that’s because of the directions the eyes face, and what’s in front of each of them. (If still thinking about this, think also about pigeon’s eyes — and ask what’s in front of each one of them). What is said here for the brain goes also for any part of the brain, including the any specific set of neurons.

The ‘self’

Similar to the eye-brain, we might say that a self-eye system defines ‘front’ for the eye. What is behind the eye is whatever lies on the same side of the eye as the self; what is in front of the eye is whatever lies on the other side.

However, where is the self so that you can even say what lies some distance or direction from it? I have no idea.

One general idea of physically-minded theorists is that, if it exists at all, the ‘self’ is in the brain. So what we’re saying is: a part of the brain + eye. See above for problems with that.

All appeals to the brain have a general problem, one brought up by Dennett in his early work.

Looking at Your Brain In Its Jar

In Dennett’s Brainstorms, Dennett tells a story about a situation where his body and brain are remotely linked, such that his brain is kept in a room while his body roams around out in the world; his sense-organs go with his body. In this story, where Dennett — himself — is seems to be where his body is. Yet, it is if anywhere, where his brain is. In the story, he is shown his brain. He stands there looking at the brain — him — in the jar. Is he standing in front of himself? If so, then, what is in front of his eyes?

If we take the self to be in the brain, and ‘in front’ for the eyes to be defined by whatever lies on the other side of the self, we get this: Dennett’s skull, and what Dennett does not see, is in front of his eyes. While what he sees — e.g., the room, the walls of the jar before his body — this is behind his eyes. If he says ‘what lies before my eyes is my brain in a jar’ he is strictly speaking wrong. This lies behind his eyes as is a lot of what he sees.

All of these solutions share a similar feature: they involve evoking something other than the eye alone. The eye inherits its direction from either something else — the earth, the body — or from something else along with the eye. Perhaps this is too complicated. We can take the eye on its own. We can say that the eye has an intrinsic direction – that is, we return to A.

Back to A. A Straight Line Running Through the Eye 

A, again, looks like the ideal candidate. We need only unpack the notion of direction in the eye. By explaining where the direction comes from, we can have a clear standard for determining visual direction such as ‘in front of’, ‘to the side of’, and so on. And through that, we can evaluate visual appearances of the same.

The eye has structure. It has a lens, retinal cells, and they all lie on different parts of the eye. We define direction this way: the retinal cells are further back than the lens; the lens are further forward than the cells.

Further, lens and cells make a line so that we can say what lies off that line is to the left/right/above/below of the line. If we define direction relative to this structure, it seems to survive every counter-example so far. If I turn my head, my eyes, bend one out the back of my head, relocate my self, still: retinal cells lie further back than the lens, and the lens lies at the front.

However, there are still problems, indicated by the following questions:

(1) There are many lines in the eye; the eye is an ovoid; none obviously stand out. Why pick this line running through lens/cells? Why not pick ‘front’ as what lies orthogonal to that line — to the side of the line?

(2) One reason is that it is a straight line. But there are many straight lines passing through the eye.

(3) And, even if it is the line, what makes that line straight rather than crooked or curved?

(4) Say it is a special line that is straight. Is a straight line wholly determined by facts within the eye enough to get us a standard for areas in front of the eye, such as objects at a distance?

I won’t go into the details of all these. They bleed into my work in my 2018 books. But for now, let’s look at that last one, (4). We may define a straight line by some linking between different elements in the eye. But how does that get us a standard for lines outside the eye? We need that to get our visual appearances: the visual appearance is of things outside the eye.

The ‘veridical’ in ‘how things visually appear in veridical perception’ depends in part on veridical direction.  Things visually seem to lie in front of us. So, what determines the veridicality of that ‘in front’?

Drawing a straight line

A natural answer is that we extend the straight line drawn within the eye out beyond the side of the eye with the retina. This straight line divides the world, such that some things fall along it and others fall in various ways around it. This straight line is the arbiter of what is visually in front of or to the side – including, in some way, what is above, below, to the left, to the right, and so on.

For example, in the figure below, the red square is in front of the eye, the triangle and star below it, the yellow circle above it. If it seems otherwise to the person looking, their phenomenology is mistaken.

Good stuff

However, this extension of the line isn’t the only way you could extend it. You also extend it in other ways, such that the objects in the world are differently arrange with respect to being ‘straight in front’, ‘to the left’, etc.


Which of these lines is the straight line? As I’ve drawn it, still the middle one. But that’s only as I’ve drawn it – as I’ve stipulated it here.

One can apply a transformation to the lines in such a way that what seems to be a non-straight line is now straight and what is a straight line is now not straight.

Each of these lines can be an extension of the line inside the eye. The line in the eye is a line-segment of a greater extension. However, it does not in itself determine what makes the whole straight. We need a frame or coordinate system of some kind to provide that. And, in modern physics at least, the choice of coordinate system is arbitrary. There are no privileged coordinate systems of this kind.

As such, what makes a straight line running from the eye, providing a means of saying what is ‘straight in front’, what is ‘to the side’ and so on, is arbitrary.

If we stop here, we have no means of judging our visual experience of direction and depth as distorted or accurate. Of course, we can always presume or stipulate something. It is possible to agree on a standard and then judge something by how it matches that standard. We might do that with dancing, for example. There is a right way and a wrong of doing the twist.

However, that is irrelevant to the underlying mechanisms of perception and its relationship to the world, even a world with us in it. We can act as if perception is wrong because it fails to correspond to some stipulated or conventional system of measurement. It doesn’t mean it is actually wrong. It is only a pretend way of saying it does not correspond to our stipulated or conventional system of measurement. I think it is more accurate and honest to say that, if that conventional system is introduced to judge such things as perception, it is the system that is wrong.

So, is that it? Can we make no judgements about visual direction and depth? Is there no such thing as visual direction and depth actually?

Well, there seems to be. So, what can we do with that? Maybe there is on final method of defining visual depth and direction. We use light. However, then we have an unusual situation: we might use light as the standard for visual perception of direction and depth: but it always comes out right.


There is a beam of light that travels from the seen object to the eye. There is also the light path it takes over time (not at any particular time, mind – and thinking of a particular time will cause great confusion; for more on this, see my 2018).

Perhaps this is the line that extends beyond the eye that we can call the straight line. If the visual appearance of ‘straight in front of the eye’ fails to match what lies along the line traveled by light to the eye, then there is distortion, mirage, looming, and other erroneous visual phenomena.

However, the reason that we get such unusual phenomena is precisely because of the unusual path the light has taken to get to us. Mirages come from light rays that typically travel up into space reversing and traveling down to the observer’s eye. But that doesn’t matter: if the light path itself defines what is straight, the path is always straight. What lies at the end of the line of light is always at a straight distance from you. And this is also how it appears: what appears to be a straight distance (including what is straight in front) of you is that way because it is a straight distance from you according to light.

As such, if we use light to define what is straight in front of you, how things seem this way visually, our visual phenomenology of depth and distance, is always accurate.

A small conclusion

My tentative conclusion here (tentative especially as I’ve not gone into any objections to it) is that the visual appearance of depth and distance (for example, of ‘straight in front of you’ or ‘to the side’) is, if we use light as the standard, always accurate and, in the absence of that standard, is not obviously evaluated by anything else.

At least, this is the case for mirage-like experiences. For ghosts, after-images etc – that is a different story.

A few small points.

First, if this works, then this is a case in which visual appearances are exceptionlessly accurate. This is something phenomenologists will enjoy, I expect. As for others, especially theorists convinced of phenomenology’s merely representational-vehicle=not-content nature, or of indirect realism, or of sense-data, or of an exceptionless phenomenal/physical split, this may be an unhappy view. But: I don’t know if it should be. My point isn’t that the visual appearances are part of external reality (or whatever it is upsets representationalists, indirect realists, sense-data theorists, etc). My point is that no arguments from illusion or error can be marshalled in defence of the opposite: there is no case of visual depth and direction which is mistaken.

Second, if this works, then this form of visual appearance can be taken as a diagnostic and theory-testing tool. It has a kind of pure empirical role. You describe the visual appearances and then look at the world according to some frame or other, e.g., the frame of the Earth’s surface (or anything else). The difference can tell you something about paths of light as they relate to it, e.g., that light is curving away from the surface of the Earth and then curving toward it again.

Third, I think the case of visual appearances’ exceptional aspects might be extended. I think you can ask what is straight in front of you for hearing and touch, for example. You can probably tell a similar story about ears, and hands, and parts of the skin, bits of the nose, areas of the tongue, nerves in the body and whatever else you hold to be the set of organs related to (a) any particular sense and/or (b) all the senses together. But when you extend beyond the body, the question of real direction becomes either arbitrary or, I suspect, links to the sense of space in phenomenology itself.

Finally, fourth: there can still be error in visual appearances. Or, rather, there can be error in how we take visual appearances. The error comes from what I call the anosognosic part of perception: the real part of perception or what is perceived that is not at all percpetually apparent and which, alone, drives a difference between perceptual appearances and the world. Here, there is no sense of a difference between visual depth and direction and the depth and direction of reference frames and other senses. We are anosognosic of that difference, where it exists. And it nearly always exists.

So, reach for a straight stick that is, unknown to you, half-submerged in a glass of water. It will seem to you as if you are about to grab a stick that is bent in the middle. But it’s not. This isn’t because the stick is mistakenly visually bent or actually visually straight. It’s because, for some frames, it is straight and, for others, it is not. Some of those frames match what we seem to see – the frames of the path of light, for example – some of those frames are not – the frames of our body or hand.

That… may sound strange and may even seem to be a serious objection with everything I’ve said so far. I know, and I talk about it in my 2018’s chapter on mirages and depth. So, to find out more, go there.

In summary, we experience the world as from a point of view, as from a particular coordinate system. That is one of many. And I think: There is no physical justification for a real and separate arbiter of the accuracy of that experience’s phenomenology of that point of view. As such, there is no real justification for calling such experiences distorted.


1. Direction and magnitude — that is, vectors.

2. A direction defined by what? This question is especially relevant given that I am talking about the direction of other things such as ansin, arguing that ansin has a different direction relative to each eye. So what determines that each eye has a different direction?

I think anything will do, even each eye, with the condition that, if the eyes have different directions relative to at least one other thing, then they have different directions; they may lie in the same direction, however, relative to other things, and depending on different ways of calculating coordinates in space, e.g., lying in different directions under straight Newtonian coordinates, but parallel under curved space.

It’s like with motion: if two bodies have different speeds relative to something, This makes direction relative, conventional and/or arbitrary, depending on how one picks out or chooses to work with ‘anything else’.

However, one might want a general answer. So, perhaps ‘anything’ could for example refer to everything — and one could say that the direction of the eye is relative to what it is relative to everything. To make that coherent, because many things face in different directions relative to each other, either this ‘relative to everything’ would have to be:

(a) A whole range of values — making the eyes ‘direction’ a set of varying directions

If the range of values is all possible values, then that set includes all directions. So, in which direction is my left eye facing? Answer: any direction whatsoever (but depending on what one is determining it from).

(b) A calculation (an average, mean, etc.) from these values

(c) Relative to everything within some domain of things

For example, electrons in the Earth’s magnetic field

One could try this: face the direction in which they move (if one wants to anthropomorphise them, and not only that, but to a normal human — no running backwards). Then, a direction ‘relative to everything’ is restrictively defined as being relative to a coordinate system determined by the average of those electron’s velocities (getting Magnetic North). useful for certain contexts.

But this is not the direction which one is forced to accept in all contexts. If I prefer to define direction according to something other than this average, I don’t see why I should also consider this direction as well.

For example, say I want to define direction relative to the path light takes between Betelgeuse and my eye when that light hit my eye one night late last autumn.  I say what’s left or right, above or below, in front and behind – relative to that path. That looks just fine.

To avoid questions of relativity, one might argue for a non-relative, or non-arbitrary and non-conventional direction to which one can then define the direction of each. However, unlike with time,  I don’t know anyone who thinks there is such a direction in space (do you?).