Intermedium §1

1.
I've left it at a rather odd place - so far as I can see, a position not seriously taken by anyone I've read in contemporary philosophy or science, nor a position I take myself. But this brief post here is not part of my writing about imagination. I've been busy fixing up a paper as a journal article and reading about the concept of space in antiquity and in the medieval tradition, so I've been busy when sitting at a computer. Also, I don't have easy internet access here. It's either the town library or an awkward corner in my parents' dining room (where I am right now).

The dining room has a bay window and a bright light, and looks out into the front garden. The panes of glass are pitch black and I can see nothing out there. But anything out there, nothing or not, can see me in here.

2. 
Though I don't want to get into talk about space for now, as I've no time, I want to mention right something I learned when reading about the old concept of space. All this is from Mark Jammer's 1929 'Concepts of Space' (preface by Einstein). From Google Books:

Hesiod referred to space or the void as chaos.  'Chaos' is gotten from the root 'cha-' which means 'yawning' or 'gaping'. What do chaos and the void have in common? They both lack form and, in the case of the void, it also lacks material.  As Jammer notes, the idea of space or the void as yawning or gaping brings out the terror of it. Like Nietzsche's Abyss.

3. 
Also, I've been babysitting. I watched 'Looney Tunes: Back in Action' with my niece and nephew, and laughed along with them. Watching movies with kids can be a lot of fun. And also very strange - it's hard to forget that they just aren't grown-ups. And: I'm not often around children in my day to day life; it's hard to figure out what to talk to them about.

Tonight, I realised that my subtle tests of their thinking about universals and particulars didn't seem to get anywhere. (This was probably because it's been raining all day, and I'm a little house-locked).

I asked my nephew 'you've seen green things - but do you think you could just see 'green' on its own?' [Subtle test of how he thinks about colours being independent of particulars].

And he said: 'yeah.'

'Really?' I asked.

'Yeah. Vegetables.'

At the time, I thought: ah, he doesn't get it. But now I think it's obviously the other way around: I didn't get it.

Then we talked about whether or not dogs can eat pizza, and then how much easier it would be if we could speak dog.

4. Oh, now I want to write about Horizon's programme on language. But I won't - I won't even link to it. I feel enough of a steamed parsnip as it is - i.e., some sort of dry, dry, dry, tasteless vegetable.

I used to go to nightclubs every night you know. The only gaping void was the dance-floor before I got on it. [No. That doesn't make me sound cool.]

[I'll talk more about universals and particulars, properties, tropes, nominalism later (whenever it seems relevant to do so, anyhow).

5. Concerning my main topic, but not my only topic, this is what I'm going to talk about next (I won't explain what these mean just now):

(a) Physicalism.
(b) The nowhere-ness of mental images.
(c) Denying we experience anything - certainly, denying that we see, hear, touch, etc. anything when we imagine - and why you'd want to say that.
(d) The homunculus fallacy and its misuse.
(d) Practicing the imagination.
(e) Memory images and the imagination.

There'll be other things as well, which I'll shove in around this. There has to be - there are so many other interesting things, and I want to go on about them.

Add To The Noise.

Projections into inner space.

'When figures appear in your dreams, what are these thoughts made of? [...] In what ways do a phantasm in the mind and an image made of light resemble each other?'

Marina Warner, Phantasmagoria

In this section, I want to discuss what I will call constructs of the imagination - real things that are of imaginary things; we might also say that they represent imaginary things. Common and unproblematic examples are things such as representational works of art, e.g., narrative films, story songs, fiction books, and so on.

It is probably obvious that we can interact with these constructs, e.g., we watch a film, pick up a book, or turn down the volume on a radio. And, in all such cases, these constructs are physical things, e.g., a film has weight, chemical composition and shape (it's a strip of treated plastic); a CD is a circular silvery disc, etc. They are also public things: the same copy of a film or book can be perceived by many differently people, passed around, picked up, or even sat on (though people, particularly artists, tend not to appreciate doing the last thing).

As such, thinking of an image itself as a physical thing is not a general problem. How the image is displayed, what it is made of, where it is located - these are questions that can, in principle, be answered in a physical way. In addition, the pictures and images themselves exist, and have shape, colour and weight, e,g., film stock, even if what they are images of do not, e.g., The Balrog in Lord of the Rings.

(Five) Senses of Images

I call these constructs, in general, images but I do not restrict this to visual images. I also mean by this constructs for other senses as well - e.g., sound-images: voices on the radio, violinists pulling on their bows. Through recordings, we hear Yehudi Menuhin or Nirvana playing at a particular time and place; or, if the recording is a mix of different sessions, we hear an amalgam of times and places (a difference we will talk about later). In either case, we seem to hear them playing; given the most fabulous surround sound, we seem to hear them playing over there . Or, at least, for convenience, we would say we hear them play over there. Yet, they are not over there; they are not anywhere now; they are gone. Only the recordings, not the actual players, not the moments they played, remain. What we hear is really the recordings. (Again, we can say something similar about seeing pictures of things; what is pictured does not exist. But the picture does).

For the other senses, there are less familiar examples. Consider the tactile sense, i.e., the sense of touch. There are not so obvious examples of what you might call a feeling-picture or feeling-image. But there are one or two, mainly related to infant's games and toys (perhaps adults just don't play so easily with such personal space).

I bought a book for my niece several years ago which had circles of texture on each page (it was about 'Spot the Dog', I think). On the first page, they had a picture of a dog, with a little circle of fur; on the next page, a picture of a red ball with a little circle of red rubber. Here, the child is presented with the 'feeling of dog fur', of rubber balls, and so on, with no actual dogs or balls being there (we hope; one would hope the fur is not actually dog, given the mass production of these books). Trying to find my book's name, I found this on Amazon - I'm a Dog, but this not the same one; it's done by Art Spiegelman; but it also seems to be a tactile book - but I haven't actually felt the book, so I can't really say.

But, despite what the last book claims, there are no dogs, rubber balls or dog-bits and rubber ball-bits in these books. There are just representations of dogs, rubber balls or dog- and ball- bits.

Another example of a 'touch-image' (as I will keep calling it here) is a children's game. This game uses the feeling of one thing to stand for the feeling of another. Do you remember 'itsy bitsy spider'? A parent slowly walks their fingers up the kid's arm, all the time reciting a rhyme -'itsy bitsy spider, went up the water-spout' -, to the mounting excitement/worry of the child. The parent, of course, is pretending that there is a viciously poisonous spider crawling up their arm. As is often said about these things, there is probably an evolutionary reason why parents do this to their kids: Through this game, the child is taught the terrifying truth that small, furry, cute creatures such as house-spiders may actually be lethal (in Ireland, this is a terrible falsehood). And they do it in a very safe way: in this case, there is no actual spider (of course, in Ireland, an actual spider would be just as safe).

(There is a version with a bear; isn't there? The bear is walking up the kid's arm from their palm. But this version never made sense to me).

There is a more modern example of touch-images. A certain type of computer-game joystick/controller/handle vibrates in response to certain situations in the game: if it's a driving game, it vibrates when the 'car' 'goes over' 'rough' 'terrain'.

What about the other of the traditional five senses - 'taste-pictures' and 'smell-pictures'? Again, what we need is a situation where what we taste or smell is not some particular thing but only represents it in some way. For smell: On my way home in the old days in Cork, I used walk past the Gate cinema and get a fantastic popcorn smell from its air-conditioning blowing out on to the street. I have never tasted popcorn like that, certainly not in that cinema. The taste never matched the smell (popcorn never does, in my experience).

However, this is not the example I'm looking for. What I've done here is used how something smells to make a judgement about how it tastes. This is related to what I'm talking about - such associations are likely to be part of our overall idea about what we think we are smelling, tasting, hearing, seeing, etc - but it is a different situation to what I'm concerned with. Instead of taking the actual smell of popcorn to mean something about its taste, I am concerned with where what we smell is not popcorn but only smells like it.

One example of this would be table polish. I grew up with a brand of table polish which smelled like pine needles, but wasn't actually pine needles; nor am I sure that the pressurised gas in the container was made from pine needles. Similarly, air-fresheners usually have some sort of sea/wood/meadow smell, as do types of shower gel, shampoo. Then there's aftershave and perfume, including, if they worked, pheromene sprays. (There is a bottle of tea tree shampoo in the shower room; I don't know what tea tree is; I'd like to say it's...what tea comes from. But is it? Anyway, I've never smelled a tea tree, except in these bottles - if that's how it smells). In general, with these: something smells like Fantastic Y but is actually just a sprayed Average X.

I just thought of another one: chocolate-smelling erasers (in the shape of bourbon creams); boy, did I want to eat them (until I ate one).

And the same, of course, with taste. As Schlosser discusses in Fast Food Nation (Amazon listing), we can make synthetic versions of nearly all flavours: vanilla, strawberry, beef, chicken (human blood, maybe?); we can then stick it in something else, particularly something bland, e.g., crisps, cereal, to everyone's delight.

All of these constructs represent but are not the real thing. For the most case, we - at least, adults - know that they are not really what they seem like. But we smell, taste, hear, see and feel them all the same as being like the real thing; after all, this is why they are even made like this.

Seeing Images

As said, in a very important way, constructs are not especially different regarding our awareness of them and what they represent. Films, books, music, perfumes and fake flavours all work on the sensory organs of our body the way everything else we sense works on them. I will discuss that in more detail later, but a brief example will do here.

Very sketchily, when I see a horse, this happens: light travels from the horse to my eye, stimulating nerves attached to my eye; these nerves then set off neural processing in my brain; this neural processing then, somehow, causes, or is, my seeing of the horse. When I see a picture of a horse, light travels from the picture to my eye, stimulating nerves attached to my eye; these nerves then set off neural processing in my brain; this neural processing then, somehow, causes, or is, my seeing of a picture of a horse.

You can do this with other sensory modes as well - taste, touch, smell, and so on - but like all philosophers only slightly educated in the ways of neuroscience, cognitive science, and psychology, I'm sticking with vision for most of this.

In order, then, to get this image or representation of something, we just open our eyes and look at it. In addition, the image is out there, and public, and physical. We see it because light shines on it. Or we hear it because of vibrations on its surface, or we feel it because it touches our skin - whatever we say, the image is experienced the way we experience other things that are real.

As such, thinking of an image itself as a physical thing is not a general problem. How the image is displayed, what it is made of, where it is located - these are questions that can, in principle, be answered in a physical way.

But, now, of when we imagine - when we dream, hallucinate, voluntarily or by request picture 'in our mind's eye', or when we day-dream; what can we say about the physics of what we experience there? Can we say the same about our experience of those images as films, perfume and children's books?

Imagine a horse; imagine seeing it. What colour is the horse? How far away is it? Which way is it facing? What is behind it? Does it fit to say this about what you experience? -: light travels from the image of the horse to your eye, stimulating nerves attached to your eye; these nerves then set off neural processing in your brain; this neural processing then, somehow, causes, or is, your seeing the image of the horse. And that is what happens when you imagine the horse.

Or consider remembering seeing a horse. Consider some day when you saw one for real; or, if you have never done so, imagine the last time you saw a picture of a horse. Can you say that you see the image of the remembered horse by the following process: light travels from the image of the remembered horse, stimulating nerves attached to your eye; these nerves then set off neural processing in your brain; this neural processing then, somehow, causes, or is, your seeing the image of the horse.

This can't be what's going on for what we imagine or remember.

The Non-existence of Imagined Things

Earlier, I discussed the idea that memories/imaginings and perceptions were different in terms of vivacity of sensation. I gave a few reasons to not think of this as the big difference; notably, it sometimes seems as if we are seeing, hearing, etc. things vividly when there is nothing there.

There is, however, a significant difference between the experience in remembering/imagining and the experience in perceiving. What we perceive exists now*; what we remember or imagine does not.

[*This is not a simple claim; given a certain understanding of 'now', half of my thesis argues against the claim. One of the arguments of that thesis, from assumptions in contemporary physics and cognitive science, can be also found in my forthcoming paper in the Journal of Consciousness Studies. But never mind that for now].

This is also true of what is represented in films, recordings, and games about spiders: what we perceive exists now; what is represented in film, music, and games does not. But the big difference between experiencing those sorts of things and experiencing what we remember and imagine is, in the former cases, something in the world stimulates the senses. The parent's fingers, the flickering projection on the wall, the low-volume vibrations in the ear-piece - all of these operate on our senses, setting off the chain of events that lead to our feeling, seeing or hearing them.

But when it comes to imagining and remembering then, no matter how compelling or overwhelming these experiences are, there is nothing stimulating our senses now. When you imagined the horse - or imagined the tactile book I described earlier - you experienced something which was not out there, out in the world which you share with me and everyone else; it was not outside your head, now.

This probably seems obvious and hardly needs stating. But I do for this reason: in the last entry, I talked about when we imagine something, e,g., a rabbit on a blue square, we are experiencing something, I have suggested that whatever we are experiencing seems to be combinations of things that are rabbit-shaped, blue-coloured and square-shaped.

But if we do experience such things, there are several questions about them: first, if they are not actually rabbits or blue squares, then what are they?  And if they're not out there in the world, aren't they somewhere? So, where are they?

Mental Space

According to Warner, the medieval (and, if he is the same person alchemical) scholar Fludd thought that, when we imagine something, we did not just see it as we see public things. Nothing we imagine seeing comes through our senses from the world. Instead, we experience an image projected from somewhere in ourselves onto something in our mind. In medieval times, such images of our imaginings would be compared to images from a magic lantern, These days, they are better compared to the images from a film projector. If we put this in the terms here, what we see, hear, etc., then, is literally a projection. This is what we have when we imagine something.

Fludd's concern with projection suggests that there is another view to which he is responding: images operate just like perceptions - we see visual images, hear sound images, etc. Fludd's revision is that we cause them in some way, rather than they happen to us. But what underlies both kinds of thinking is the idea that the images in our mind are just as see-able, touch-able, etc., as objects in the world. It's just that they are projection in our minds.

But does this tell us where what we imagine is located? Not really. All it says is this: what we imagine is projected 'in' our minds. But 'in our minds'? - where is that?

We might start by saying that image is where it seems to be. This raises yet another question. Where does the image seem to be? By 'seem to be' we could mean one of two things: where what the image is of seems to be or where the image itself seems to be.

The location of what the image is about doesn't seem relevant: it is commonly somewhere public and certainly not 'just' in our minds. Think back to imagining the horse - where did you imagine seeing it again? Is that also where what you're the image is when you imagine the horse? Or, say you dream about being out in the depth of space fighting aliens, were the images you saw in your dream really in the depth of space?

It seems as if what we imagine can be anywhere in this world. It can even be in places that don't exist, e.g., Gotham City, Bognor Regis. So, where what we dream about or imagine takes place could be anywhere, even somewhere non-existent. But I don't think the image can be in these places. If we experience it, it can't be somewhere that doesn't exist. And even if what we imagine is somewhere that exists, it sounds bizarre to think that the image is there as well just for that reason. This would be claiming that, if you imagine the horse as standing outside the back door, then the image, what you are experiencing, is also outside the back door.

So, we still have the original question: where is what we experience when we imagine something? Where is the image?

We might, at this stage, ask where the image itself seems to be. But this is where I find things get difficult. When I imagine a horse standing outside the back door, the imagined location is easy - outside the back door. But where the image seems to be...I'm not sure I've any idea at all about that one. First thought is this: if it seems only to be an image, it doesn't seem to be in the world I can interact with; it doesn't seem to be in the world that you and I share. But, other than this negative appearance - it doesn't seem to be somewhere I can go to, or tell you to go - I can't with any certainty say anything about where it seems to be.

By default, I suppose I'd say that the image is in me, i.e., the image is in my mind or in my head. It is, after all, my image, my imagining, my imagination - so it seems fair enough that it is somewhere inside of me, if it's anywhere. And I think most people would at least speak that way - 'the mind's eye', again - and understand such references when asked to picture things. Say I ask you to imagine or remember the horse, and you start drawing a picture of the horse. I can tell you 'no, don't draw it; just picture it in your head', I think you'd understand what I mean - I mean 'imagine it'.

On the face of it, I think that this is a fairly common thing to say. It might very well be where images are (which I'll discuss in a later section). I do, however, think it also raises certain commitments which cause problems. But this concerns either what we're in the habit of saying or else how the images really are. But, think for a moment: when you're imagining, does the image seem to be in your head? Do you have that sense of place for your imagination?

What makes something seem to be in your head? Is there anything like that? Well how about this. Say you have a headache - you can easily locate that pain. It's there, behind your temple. Say your eyes are tired - you can feel the weariness, ache and soreness on your lids. I had neuralgia once - my face sagged and I could feel the sharp and constant pain down one side of it. There's the throbbing of blood in your ears. And the taste of chocolate can seem to be in the mouth, which is in the head, so...some things can seem to be located in my head.

But does a mental image seem located like this? If so, it should seem to be located at some place in our heads; or even if it's not at any particular fixed location, we should have a vague sense of it being somewhere  in our heads. Such imprecise 'it's in here somewhere' can be compared to the most awful of awful toothaches (anyone who's had one knows what I'm saying).  Imagine a sunny day last year. If we're right about how images seem, I can say, just by how it seems, that the image seems to be located somewhere, e.g., in the front right corner of my head, just above and behind my right eye. Or it seems to be spread around the middle of my head, i.e., throughout my brain.

Is this something you have experienced when you imagine? Would you be surprised if someone told you 'you know - when you imagine seeing a sunny day, it actually happens in your heart. Or in the back of you neck.' Would you think 'what? How strange! It has always seemed to me to be just behind my throat!'

For myself, I don't have this sense of location for images. I do have it for what I imagine (to some extent; something I also want to talk about). But images themselves: they just don't seem to be  something whose spatial location is as identifiable as (i) what I perceive in the world, e.g., the stuffed pheasant staring right at me now, or (ii) what the images represent, e.g., the horse in the field used throughout this discussion (this is imagined; there are no horses (or pictures of them) at all in view). If this is right of people in general, we can't tell where images are from where they seem to be - because they don't clearly seem to be anywhere.

So, again, where are images?

Let's go back to the medieval alchemist Fludd. According to the view I'm taking (or possibly just adapting) from Fludd, the location of images is literally in some sort of private space; this is where they are projected. This space is not connected to the public space you see, hear, touch and so on.

In this private space, all our imaginings occur: all our dreams, nightmares, easy wish-fulfillments, half-baked fantasies, hallucinations, overwhelming memories. And we might have a similar process for how we see them. We may be stimulated by them, which then sets off neural processing, and so on, until we see them.

So, where we have a physical eye for the public world, we now also have a 'mind's eye' for the private one; and this mind's eye is stimulated by visual images, e.g., imagined blue squares. Where we have a physical ear for the public world, we now also have a 'mind's ear' for the private one; and this mind's ear is stimulated by sound-images, e.g., hallucinated voices, the complex sounds Beethoven heard in his head in the last few years of his life; he wrote as symphonies, even though he was deaf and so never heard them in the public and physical world.

We could think of this space as a little theatre if we wished, perhaps as a 'Cartesian' theatre; I'll discuss that view in more depth later. But why suppose the private space is 'little'?  A little theatre would suggest that there is some obvious limit to a private space. But if it's a private space, what could that limit be? The limits of the brain? But the brain is in the public space; the idea here is that what is in the private space is not what is in the public one. This is just why our images can occur without there being anything in the world.  So, if you go for this view, this private space could be any size, even as big as the public one (whatever we could say that size is).

Do you think that this solves our problem about where images are?

No.

Are there any problems with it?

Yes.

Images, imagining and remembering

Whether I like it or not, I often think of myself as somewhere other than here. I don't live only in the present. I'm not a tree either: I'm not rooted to this spot; I have been in at least one other place, even if it is only where I was born. So when I think about myself, who and what I am, I do not think only of myself at this moment in this place. Instead, I think of myself as I am at different times and places.

I am not all here in another important way: many things that occupy my thoughts and a lot of situations in which I see myself are not real – or, at least, are not obviously real. I think about the future, I imagine it, I worry about it, but I never, in doing so, am actually there in it; I don't even know if I will be in it. I might think of tomorrow as another dull guilt-ridden day in my home-town but it might not be. It might be nothing for me because I might die tonight. Tomorrow might never come.

I also remember scenes, books and films which are entirely fictional. And I day-dream. I imagine conversations I should have had, killer lines I should have said, relationships I ought to have avoided, and situations I would like to be in; yet, although I think of myself as in them, I know that these can never occur. Still, I fill some of my time with them, often for the pleasure of doing it, but I sometimes even when doing so can only cause me pain. The imagination is not always under one's control (or....else....I'm a masochist).

When I do imagine some of these scenarios, or worry about the future, or relive the past, I can get lost. I can forget where I am now. I'm walking down a street thinking about the last time I was in Cork - who I talked to, what we said - and I'm imagining what I could have said otherwise, then I realize I've already walked by my destination at the bank. I was so obsorbed in my reminiscence that I hadn't noticed.

This is something that commonly happens to all of us, but I still find certain features of it curious. I don't find my failure to notice the bank curious; one could easily think of that as a failure - the failure to notice something - a failure to experience something. What I find more curious is what, we might say, I was experiencing when I was so distracted. What do I experience when I am so deeply remembering or imagining? Do I experience anything at all?

Pictures in the Head

According to the psychologist Kosslyn, when people imagine things there really is something they are aware of. And what they are aware of is something like their perception of the external world. There are features to what we imagine that are not just hearing our own voices describing them (internally or externally), i.e., imagining is more like looking at pictures than thinking with words. There is something it is like to imagine something which is not just saying what you imagine. (e.g., Kosslyn, S. Thompson, W.L. 2006. 'The case for mental imagery.' Oxford, Oxford University Press)

The idea is that people have a mental image or mental picture in their mind when they imagine something, and we seem able to do things with that image which we can do with objects in the world: we seem able to stand back from it,change our perspective on it, add features to it, and even discover features of it which are not obvious when we first think it. Try it for yourself to see if you agree, e.g., imagine a blue square. Cover it in red polka dots. Next, put a rabbit on it. Now, what colour is the rabbit? How big is it in comparison to the blue square? Now put a leprachaun beside the rabbit - which is bigger? What's the leprachaun's expression? Imagine the leprachaun laughs - what does it sound like? How does the rabbit react?

Whatever it is that might happen when we imagine something, it does seem as if we have mental images or sensations when we remember. But how are such images and sensations related to what we perceive, i.e., to what we see, hear, and so on? The seventeenth-century philosopher David Hume thought that the sensations or experiences which we have when we imagine or remember something are distinguishable from those of perceptions by being less vivid than what we perceive. Other thinkers actually deny Kosslyn-type positions, i.e., that we have some kind of experience when we imagine or remember; I'll discuss that below. But if we do experience something when we imagine or remember, it may seem as if there is at least a difference in vividness. But I do not think so, for the following reason.

Many people who suffer particularly traumatic events often report remembering the events so vividly that it as if they are seeing what happened, hearing what happened, feeling what happened all over again. One example is discussed on 2007's BBC radio 4's 'The Memory Experience': a fire officer suffering post-traumatic stress disorder after a particular fire suddenly found himself reliving it - hearing the sirens, seeing the lights - when he saw a flashing blue light in his back garden (I think it was a faulty burglar alarm 'The Making of Memory: Is it Better to Forget Trauma?'). Chicago Public Radio's 'This American Life' (October 23rd, 2009) tells the story of a man who escaped arrest by the law for murder – but didn't escape his own conscience; in the years following, he could not forget his crime, and sometimes 'replayed' the events so vividly that it seemed to him as if the images of it were playing on the blank wall of his room, even though he was awake (I lump dreaming under imagining in this discussion).

Under vivid memories, I would also add in another very unusual and famous class of sensation and experience, one which is famous in contemporary literature on consciousness - phantom limbs. This is where an amputee still feels the amputated limb as if it is still there, even though it is gone. Again, what could only be something remembered seems to be perceived.

So what we remember seems to be something that could be as vivid as what we perceive - but there is also what we experience when we are only imagining, when what we may sense of experience is not happening and never was happening. People also report powerfully vivid experiences of what seems to them to be real but which is not, i.e., hallucinations (e.g., see the opening chapters in Julian Jaynes' 'The Origins of Consciousness in the Breakdown of the Bicameral Mind'). A most common kind of hallucination is auditory hallucination, in particular hearing voices (information and support on this, see the 'Hearing Voices' website; also, recent research suggests this is more common than one might think (BBC, 18th September, 2006)).

Another example might seem obvious: what we experience when we dream. Unless we believe that we literally travel to some other place when we dream, we are experiencing things which are not actually in the world around us now, and in many cases never were - but still, we often believe they are happening.

Lastly, there are numerous illusions which show phantom motion, colour, that seem to be of seeing things out there - on the computer screen, etc - which are just not there (see Michael Bach's webpage).

All of these situations seem to be demonstrating that, first, when we remember or imagine something, it can be just the same as actually perceiving it; this suggests that we experience something like what we see, hear, taste, etc., when we imagine things. In addition, as with the guilt-ridden man or people who know what they're seeing is an illusion, we can know what we are imagining or remembering is not really perceiving it, yet still it can be as vivid as it.

What about where you voluntarily imagine or remember? Can you remember the blue of this summer's sky? Have you ever had that experience where you can suddenly remember exactly the touch of someone you once loved? Can you recall the taste of refresher bars or your own blood? (I take it you're not tasting either of these right now). Or let's be more mundane: do you remember the circle you had to draw with a compass in maths class? I can see myself now: sticking its tip into the paper and turning it unevenly in my hand. The spike is barely stuck into the paper; the gold-coloured metal is cool and the pencil scrapes and wobbles along the page.

This resemblance is not so clear when you voluntarily remember or imagine; in this case you might think that there is a difference in the vividness of remembering/imagining and perceiving. But don't you still experience something in these cases - in some way taste, hear, see, when you remember or imagine? When you imagine seeing a square box, you may not be seeing an actual square box - that is, something that is sitting somewhere in the world - what you see may not be very clear, but isn't there in some way an actual square? Aren't I in some way experiencing a square?

There are problems with that.