Horses have an inter-ocular transfer between the eyes, just as humans do. It means that e. It gives the rods and cones a second chance to capture the photons, at the expense of loss in acuity since it scatters the light. The tapetum lucidum primarily reflects light coming from a downward angle. Thanks to this, horses can confidently move around in what we humans perceive as total darkness.
The difference between day and night is much less dramatic for a horse than for a human. Another feature with equine eyes is that detected light photons seem to be added from nearby light receptors to increase the visual contrast, although at the expense of some loss in acuity. In CCD photography this is called the Blooming Effect, which must be considered by astronomers involved in measuring light variations from distant stars with high precision thru photometry e.
The definition of blooming is when the charge in a pixel exceeds the saturation level and the charge starts to fill adjacent pixels. The next part of this series on Equine Visual Perception will deal with color vision and binocular vision. Horses and humans visually conceive the same surrounding environment very differently because our eyes are different and because our evolutionary preconditions and experiences are different, but we do share the same world. When watching horses interact out on a free range it is easy to realize horses seems to benefit from good eyesight, just as we humans do.
No one has a complete explanation of the differences between equine and human visual perception, but the more we know about it the better we can understand the sublime details in equine behavior most people never even see. This subject has undergone several changes since the days of Xenophon BC and his written works on horsemanship of his time.
See a Problem?
By his experience horses had an excellent ability to see over vast distances. Legends of the Arabian horse cultures tell the same. Then during the early years of natural science, another less flattering view upon the blurry equine vision was proposed, which has lived on until quite recently. We need to change that, because now we know better.
However it is wise to point out that even if it is with the most humble intentions of accuracy, errors are inevitable as time will always prove time and again, which by the way reminds me of a poem by Alexander Pope:. Since we yet cannot connect an equine optic nerve to our own brain we cannot know exactly how horses see. At best we can find out about the technical specifications of the equine eye, but that alone does not tell us exactly how horses experience their own eyesight.
Let us begin from the basics; vision is just one of many senses that help us interpret the reality around us. Our eyes receive light and transform it into signals compatible to our brain, as an input to create one important piece in our complete perception of the immediate surrounding reality. Light is electromagnetic radiation. In some ways it behaves like a wave and in some ways it behaves like a particle, or a package of energy. The best present explanation is that it is a point-like particle called a photon, an elementary particle which has no mass and no electric charge.
In vacuum it travels at a speed more or less equal to seven laps around the earth in one second. The shorter the wavelength the more energy each photon represent. The visible spectrum for us humans is between nm and nm. Equivalent to about oscillations across the width of a single human hair. Short wavelengths are perceived as blue and long wavelengths are perceived as red. Even longer waves, beyond the visible spectra, is low energy radiation; infrared radiation, micro waves and radio waves. On the shorter side, shorter than the visible spectra we find high energy radiation; ultraviolet radiation, x-rays and gamma rays.
It is basically the same physical phenomena, only different wavelengths. When these photons of light, originating from nuclear processes in the core of the sun or from another source like a light bulb , comes rushing in a complete mix of a variety of wavelengths and hits an object they bounce off, but not all of them. So we do not really perceive anything as it really is; we only imagine virtual models out of bouncing photons.
However it serves its purpose very well for humans as well as horses; we can see. In the next part of this series on Equine Visual Perception we will begin to scrutinize the internal features of the equine eye as compared to our human eye. We are Nokota horses. On hot summer days we graze out in the field all day, but when the bugs gets too annoying we take a siesta and hang out by the front porch at our barn, away from the sun, away from the bugs.
We accumulate a lot of raw energy from all that resting and grazing. Late in the evening when the sun gets below the tree tops, or on any cloudy day like yesterday, we turn up the heat and show our real colors. Her first three years of her life she spent in North Dakota at the Kunz family ranches, where she learned a lot from her mother Black Spotted Socks and all the other Nokota horses. She is a proud blue roan and perfectly aware of her beauty.
She is the calmest and most trusty of horses, steady as a rock but also a bit shy, but make no mistake; underneath that calm facade unimaginable powers lurks. When her face switches expression she takes the lead. To catch her picture with a camera is not easy, it takes a fast well-oiled shutter, patience and a truckload of luck. She seems to like the camera though, so she gives us many chances.
She is also very cool as a typical Nokota horse and very self confident. Bluebell can be a bit jumpy at times, probably because her mother taught her to be careful and always look out. Windflower is a quiet horse and easy to work with and loves attention, but she demands respect. I am convinced she can read thoughts so one must keep ones mind quiet when working with Windflower and with the right approach she welcomes you to her world with a big Little Missouri badlands grin.
Wild Prairie Rose is our youngest, she is two summers. She came to us as a small filly freshly weaned from her mother Lucky Dust who was born in the wild and removed from the Theodore Roosevelt National Park in Her beauty is impossible to catch in a photograph. She is a light blue roan, but her appearance bear witness of many fine ancestors in a colorful past. A wonderful horse friend both competitive and safely calm. This was a summer postcard from the Werner family in Sweden, we hope you enjoy the look of these wild horses from the northern plains.
The horses are here in Sweden to stay and in the future there will hopefully be many more. Together with their relatives in Linton North Dakota they make up an endangered breed of horses. Rate this:. Feeding procedures often means that a full ration of hay and grains are given three times a day, same amount each time, each day, regardless of season. Horses tend to drink less water in winter to reduce heat loss, especially if the water is ice cold.
There are basically five different types of cells in the eye retina that receives light and transforms it into signals compatible to our brain: Light receptor cells; rods for black and white and cones for color. Horizontal cells; primarily unite signals from cones. There are three types.
Amacrine cells; some converge signals from rods, but there are 22 different kinds of amacrine cells and they do a variety of different jobs, many yet unknown. Bipolar cells; a kind of amplifiers connected between light receptors and ganglion cells. Some connects light receptors via horizontal cells.
Ganglion cells; the transmitters that sends the visual information to the brain. They come in different sizes and connections.
Reality, Meaning and Knowledge
The situation bears no relation to that of a map, diagram or model. The second point, which I am gradually arguing towards, is that real goings on do not, in themselves, on their own, have any appearances. Note that this is a sense that cannot be constructed from the individual words taken out of context. The dynamic patterns determine indirectly the patterns of appearances or manifestations to us but these are not the appearances of the goings on how could a sweet taste be what the goings on in sugar and saccharine molecules are like?
At this point the distinction may still seem obscure but it may be clearer following an illustration. If I turn to an ordinary perceptual situation it may become clear why I think the shortcomings of both direct and representational accounts of perception are based on much more pervasive considerations. I apologise to physiologists who take the following as obvious, but they may find a few novel twists at the end. Having turned my gaze away from the table, I am currently looking at our blue enameled AGA cooker.
As I pass my gaze over the cooker front I sense that the entire front is the same intense rich dark cobalt blue. There is not a hint of an inconsistency in the colour of the enamel, no fading, chipping, discolouration with use or whatever. Yet, if I introspect a little I can see that my opinion about this constant colour is derived from a totally inconstant spectrum of light reaching my eye from each part of the cooker front. Some areas are in deep shadow, reflecting almost no light. In other places the shiny enamel reflects bright highlights. Yet other areas reflect yellowish tinges from the beech flooring or white grid patterns of light from a French window frame.
What in fact I mean when I say that I see that the cooker front is a constant blue is that I have unconsciously inferred that every part of the cooker front instantiates the same disposition to reflect certain wavelengths of light preferentially. However, all I require the word to imply here is a certain sort of indirectness requiring outcomes of comparisons. I will return to its full meaning shortly, and in more detail in the section under knowledge. I use the awkward word instantiates to avoid a potential linguistic pitfall.
I am implying that with every bit of cooker front you get the same disposition operating — no more and no less. I am not being directly presented with an intrinsic quality of an object, but with a sign or signs of a relational disposition. Moreover, this disposition is complex. It includes both a tendency to preferential scattering reflection of short wavelength light with highly efficient absorption of other wavelengths and a different tendency to reflect, without scatter, all wavelengths equally, in the way that a mirror does the shinyness.
As such I see it as an evenly shiny deep blue cooker. Of note here is that I do not see paler blue where there is a superimposed faint reflection of a white door frame. I see a deep blue cooker reflecting a white door frame. It is easier to appreciate the need for this with a dark shiny surface than a pale matt surface. It tells us about the way normal vision works. If you look around most of what you see is likely to be more like a shiny cooker than an evenly illuminated matt surface. The crux is that this is in no way seeing directly how something is.
I see an evenly shiny blue cooker. We have to recast it in terms of new concepts that match with what is really going on. Even in terms of disposition, as I shall come to next, blue is not one but a collection of quite different dispositions, which happen to share mental signs. Childhood blue is what I shall call a pseudoconcept. In exploring what is really going on in the world pseudoconcepts crop up with great regularity, which is my reason for being sceptical about the philosophical idea that we should respect ordinary language use. In this field, much of it turns out to have no real referent.
I have already slipped in a number of terms without too much definition, including goings on, change, dynamics, disposition, cause and manifestation. This is deliberate because the meanings of these words that I think most useful can only emerge once I have brought together a range of background issues.
Moreover, the meanings are going to be multiple and context dependent. I could introduce new words but I think that may obfuscate. What I can say now is that dispositions are the same as causal powers or tendencies. Dynamics are patterns of change that are instances of operation of causal powers. However, I will subsequently suggest a subtle but important relation between aggregate dynamics, or everyday goings on, and individual dynamic packets.
Manifestations are how things appear, or what they are like to something but, again, I shall introduce a relation between two possible meanings with different scopes. Manifestations may also be instances of operation of causal powers, which is initially confusing. I will try to make clear how I am using these terms but I will use them differently in different places, as I believe is inevitable given the structure of natural language. Hopefully the non-verbal ideas will emerge. They signify patterns of operation of causal dispositions, not intrinsic qualities of objects.
There is an instinctive sense that to be blue is not just a tendency or disposition to reflect light but actually to do some blue reflecting. However, if asked if my cooker is blue when I go out of the room or on a moonless night when it is in complete darkness most people will say yes, it is still a blue cooker. To be seen to be blue requires that disposition to operate in such a way that we can infer the disposition but has only a very indirect relationship to the amount of blue light arriving at any particular point on the retina. If this is a statement about a tendency of the tomatoes, whether the tendency is being cashed out by red light rays bouncing off is not relevant.
We have an ordinary language phrase to illustrate this. When we say tomatoes only look red we seem to be saying that we realise that the conditions are so atypical that we tend to infer the wrong reflectance disposition for the surface of the tomatoes. We are still talking in terms of reflectance. It might be sky or ceiling or a coloured card. This does suggest that we can see blue directly. Thus, one might argue that there is a difference between knowing something is blue, even in the dark, and seeing it to be blue and that the latter is crucially dependent on getting a raw blue signal right at the beginning of the sensory process in the retina.
But, as indicated above with the blue of the cooker disappearing when looked at hard, it is not that simple. In the second case blue does not seem to be a property of anything. We explain this by saying that the light coming in to the eye is blue, but if this is a property of the light it is completely disanalogous to the property of the cooker and again disanalogous to that of a blue light emitting diode. What this emphasises is that perception involves inferences that have to draw on relational aspects of patterns of input signals.
If we can infer the presence of a cooker we can then infer a disposition for the cooker. If we cannot infer anything to attribute blueness to we have to infer a disposition that operates at some other point in the input causal chain. This raises two points. Some of the signs sent out from our collating apparatus may turn out to be generated in response to several quite different dispositions because these are often associated in causal chains.
Moreover, these signs in themselves may give no indication what disposition they actually signify. My earlier suggestion that the collating apparatus infers dispositions was intended to entail a very limited interpretation of the word infer. All that is required is that they have a collating system that generates outputs that correlate to dispositional patterns in the world. Some would argue that the generation of signs in response to patterns of disposition by cross-collation of inputs is not true inference. That there is more to some sorts of inference I would not deny but exactly what may be poorly understood I will return to this issue in the section on knowledge.
While being sceptical we might perhaps argue that the shininess of the cooker is only a property of the most superficial layer of the enamel and the blue is a property of the pigment embedded in the transparent vitreous matrix of the paint. Perhaps the cooker is in fact the deep blue colour and the highlights created by the shiny surface just interfere with our appreciation of the blueness in some places. However, the depth of the blue and the highlights are interdependent aspects of a single complex reflectance disposition.
If there were no shine the blue would not be deep; blood red marble looks white before it is polished. The question of different layers having different dispositions does, nevertheless, raise a different point. The deep blue is a dispositional property of the enamel, not of the rest of the cooker, which is mostly cast iron and stainless steel. The front of my AGA cooker that I took to be an even deep blue is in fact made up of a frame plate on to which are loosely hinged three door plates. So, when I say I see a blue cooker it seems that what I mean is that I am inferring various dispositional features manifest to me in one way or another as part of the goings on within certain spatial and temporal domains.
Language obscures the real situation. Ideas of objects may allow our collating systems to learn to distinguish, and generate signs for, the distinction between the blueness disposition of cookers and the blueness disposition of light but this may come at the price. The discussion of the blue cooker raises two important questions for our understanding of physics.
Do these dispositions belong to objects or are they, for instance, just local features of a universe? These may seem to be issues for armchair philosophical debate. However, I would suggest that they are not, for two reasons. Firstly, sorting these questions out may show us why modern physics is in fact no stranger than the old physics. The mysteries people often talk of simply disappear.
Secondly, sorting them out may provide a way of working out the nature of the human subject to which the world seems to be manifest in experience. Before addressing these major questions I need to consider two difficulties with the idea of dispositions, discussed in the philosophical literature. I might have avoided these problems, at least in part, if I chose other terms, like causal power, but my impression is that all the terms in this area suffer from conflation of meanings to much the same extent, if in slightly different ways. The second difficulty is with the idea of dispositions existing, or being instantiated, without that requiring that they are ever manifest.
In what sense would the disposition to reflect blue light be actually present for a cooker enameled in the dark and assembled in the dark and smashed to powder before ever exposed to light? The need to take this issue seriously was emphasized by CB Martin. Although Martin makes some important points in favour of thinking in terms of dispositions I shall argue that they always exist as instances of operation, and in that sense are always manifest. Moreover, we have no reason to ask for anything underlying them.
The cooker in the dark may seem to contradict this but I will argue not. The real difficulty is in defining dispositions in the right terms. In philosophy a popular example of a troublesome dispositional property is fragility. A fragile vase can be said to be disposed to break if hit by a hammer. We tend to think of this disposition as being grounded in some intrinsic aspect of the vase.
It is also easy to feel uncomfortable about the idea that vases that can never be hit by hammers are still endowed with this disposition. Think of the disposition of Spode vases to break when trodden on by dinosaurs. These two problems are interrelated. To avoid having genuinely present dispositions that are defined by realizations in situations that can never occur we appeal to qualities. Perhaps the fragility disposition does not exist all the time, only some underlying features of the china relating to chemical bonds between atoms. There are two ways one can think of this. A traditional view would be to say that the vase is in fact an aggregate structure, consisting of a collection of molecules that are bound to each other in the way typical of china.
Such an analysis seems to work in a wide range of situations. They are dispositions or powers to retain proximity under certain circumstances and not otherwise. So there is no real difference between the type of property at the two levels. We seem simply to have shifted disposition to a smaller level. Note, however, that at small scale the sort of definition we need for dispositions tends to become evident. Similarly, fragility is equally a tendency to hold together if not hit or dropped and break if hit or dropped.
Something that disintegrates without impact is not fragile. Remaining intact is just as much a manifestation of fragility as coming apart, if it occurs under the appropriate circumstances. A possible weakness of the aggregate view of the jar is that it is tantamount to suggesting that there is no real jar entity to be fragile, just an aggregate of molecules with microproperties. This may be a salutory reminder that in a whole range of contexts, like AGA cookers built in to a kitchen, a lot of properties we ascribe to large functional complexes are really better seen as properties of components.
Yet we might still want to consider a vase a legitimate entity with regard to fragility because the fragility may not just be a function of molecular binding. It may reflect an elongated narrow neck, or protruding handles. Little chips of china are not fragile in the same way; they do not crack when dropped.
A vase is something that you can pick up and turn over rotate in one piece, unlike a pile of books. Even the reflection of transmission of light by a vase is partly dependent on its macroscopic modes. I will argue later that these modes are as real entities as others. The fragility of the vase can be rephrased in terms of the stability of elastic alias acoustic modes.
A glass that shatters when someone sings a high note is showing that it has an acoustic mode that, when inhabited by sufficient energy of vibration, self-destructs. Fragility then becomes a dispositional property of a single entity. Either way, it looks, so far, as if whichever level we look at we have dispositional properties that are always associated with some sort of manifestation. The next step in the argument is to ask whether we think that either the molecular binding in the first case or the mode in the second are in themselves underlain by some non-dispositional qualities.
However, ever since quantum theory provided us with an explanatory, rather than just an empirical, theory of chemistry, the chemical bond has turned out to be something that we can only understand as some form of dynamic disposition of the patterns of electron orbitals around nuclei — a disposition to maintain proximity. If we then ask about the electrons we find descriptions in terms of mass, charge and spin.
Negative charge is a disposition to repel negative charge and attractive positive charge. We know nothing more about it than that. It is dispositions all the way down. The philosophers may still object that although we can only know these properties as dispositions they must be underpinned in some way by qualities of things.
The argument is that you cannot just have little patches of powers, powers must reflect qualities of what has them. I want to come back to this later because the arguments tend to get rarified. However, at this point I would simply ask what could possibly be meant by such underpinning qualities if they are not in themselves dispositional. Would not underpinning imply a disposition to bring the disposition along too? If there is no underpinning quality belonging to some thing then how can the disposition belong to any particular thing?
This concern fits with our instinctive childhood approach but has never been much to do with physics. I shall return to this issue shortly. What does seem reasonable is the idea that dispositions cannot just exist as abstract tendencies an example of the more general problem of the existence of abstract universals. For this reason I think it makes sense to suggest that a disposition only ever exists as an instance of operation — as a pattern of goings on. That is what makes it real rather than just a mathematical structure.
If the disposition is fragility and in a given case breakage does not occur, the disposition, as fully formulated, has still operated, because it is a disposition to break under some conditions and not under others. If it is being blue in the sense of reflecting twice as much of the incident blue light as of the red, this disposition can still be said to have operated when the amount of light for both colours is zero.
Whether we say the disposition is manifest is a more complicated question that I will address later. Things staying the same is as much a part of what is going on as not staying the same. It is in a sense still a pattern of dynamics but one with some zero values. It is still quite a different matter from what is manifest as a result. I have so far not distinguished between the need for all real dispositions to be instances of operation and for them to lead to manifestations. To equate these functions will do for the purposes of this section but will need unpicking later, as I think there are at least three conceptions of manifestation, two legitimate and one illegitimate, which need to be explored.
Moreover, manifestations are themselves dispositional in the sense that they contribute to causation. My aim at this stage is simply to indicate that we need to replace our concept of stuff with concepts of disposition or causal power. At this point I need to deal with various issues about the context of dispositions, before returning to the question of whether all features of underlying reality are dispositional. Key point: although philosophers have raised various problems about dispositions there are reasons to think that all we can know of the world are the instances of operation of patterns of dynamic disposition.
Objects are entities that are a certain way, in a certain position, of a certain colour, weight or size. As indicated above, these definitive features of objects may not be quite what they seem. Inasmuch as we know them we know instances of operation of dispositions. This calls into question whether or not we really have a clear understanding of what we mean by objects. The word object seems to imply a dynamic role; -ject comes from to throw. However, the dictionary suggests that this role can be as varied as something presented to the mind or something to which something is done.
In fact, most of us probably think of objects as non-dynamic: as things that just are a certain way, and only as a byproduct get involved in relations to other things. If we insist, as some philosophers would, that we see or perceive objects rather than signs of objects or goings on because that is what seeing and perceiving mean then we need to be careful we do not have a circular definition of meanings. That does not mean that seeing is just passively receiving input.
It requires the brain to actively compare different inputs before recognition of an object is achieved. The problem that we have with language is that we assume that its constructions relate unproblematically to what is really going on in the world. A construction of subject, verb and object is seen as a straightforward indication of some sort of dynamic relationship in the world. Seeing is a pseudodynamic idea that seems to refer to some dynamic relation but in fact does not.
If we want to give a truly usable dynamic description we have to recruit different sorts of verbal construction. This seems to imply that the language we have at present, and the way we use it, are all that are possible. It seems to imply that we cannot have useful and meaningful thoughts for which we have no words readily available. As a practicing scientist this strikes me as patently untrue. Science is all about having new ideas about the world that we then have to create new language to describe.
Ordinary life would seem to work the same way.
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Moreover, in mathematics new languages are constantly being devised to handle new thoughts. If we want to clarify our thoughts about the world we should be looking for more subtle language forms to suit new ideas, not to find ideas to suit the language forms we have. So it is not going to be any good defining objects as things that we can see or perceive. That seems a reasonable start. However, there are two caveats relating to the two questions raised previously.
Secondly, we have to consider how the mind can know which signals relate to which objects. What are presented to the mind are signals; objects have to be inferred from the way these signals behave under various different conditions. It is not clear that our ways of dividing up what is presented to us in experience are good ways, or even that dividing up is legitimate.
It is hard to see how we could infer anything about any non-causal properties of objects since they could not be responsible for us receiving any signals. It certainly does a lot of that, but that is not ultimately what science is for, its real job is to relate our experiences to what is really going on — to relate cause and effect. The signals we receive from the world may be said to represent the world in a loose sense, as loose as the sense in which members of parliament represent people or a flag represents a nation.
What we would not expect is for these signals to resemble the causes that determine their patterns because they are not themselves causal dispositions, but rather some of the things that the dispositions are to be cashed out as, and very indirectly, at that. We have images that signify certain patterns of operation of disposition but are not images of those operating dispositions. This point goes beyond the point that the neural processes that make someone sense red will not look red to a neuroscientist peering at the persons brain with a microscope.
But the dynamics inside our brains that generate the manifestations we behold are totally invisible to us. Moreover, they would not be expected to share parameters with what they signify. If we see three oranges there is no reason to think that what is manifest to the internal subject includes something in triplicate, any more than any of the words in this sentence come in triplicate.
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It is easy to assume they should, and there is no doubt that there will be triplication of certain events at early stages of the sensory process, as in the retina, but we would expect the final manifestation to the internal subject to be based on a sign of triplication, not three similar signs. If not, it is hard to see what all the pre-collation mechanisms are for — why not plug the retina straight into the soul! The signs manifest to the subject will be organised in a way suited to decision making about the world, not to modeling the external objects to be decided on. Objects, as separate parts of the world, that are a certain way, and are presented to us as separate things that are that way, are fictions of our childhood view of the world.
Like Ladyman, I think they should go. What we have reason to think exist are patterns of operating disposition, or goings on. Some of these pattern packets have much the same domains as childhood objects, but the two categories should not be confused. Moreover, my motivation for considering there to be genuine individual entities is not to provide objects. Ladyman is right in this respect — we do not need them. What we do need are subjects, of which more in due course. I think it may be more useful to think of packets of disposition as aspects, or perhaps properties, of the world as a whole.
Modern physics strongly suggests that we should think of them simply as asymmetries of the universe. If individual entities can only be conceived in terms of dispositions it seems redundant to regard these dispositions as properties of the entity rather than just the entity itself.
Key point: the everyday concept of an object is not a good basis for building a view of the world. Instances of operation of dispositions are best thought of as patterns in the world rather than properties of objects. Sometimes these patterns fit quite well with the domains of everyday objects, but that does not mean that they are equivalent to the everyday concept of the object. Another aspect of the idea that our perception of the world is via an internal system of signs is that the sensations human subjects have when we see, hear, touch or smell things must be entirely dependent on the sort of collating apparatus we have.
Thus my blue cooker can only be blue, in the sense we think we share, for observers that have not only the same set of retinal receptors, but also the same general methods for sorting and collating initial inputs. We are taught at school in art lessons that there are three primary colours — red, blue and yellow.
We are then taught in science that the there are three primary colours — red, blue and green.
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The precise reasons for this may not be clear but there is at least one plausible explanation. We also have colour-indifferent photoreceptors rods. This means that the simplest distinction the visual sensory system has to make is a light-dark one. If we then add in whether or not blue-sensitive receptors are being stimulated we have two possibilities for any perceived brightness — brightness accounted for by blue light or brightness not accounted for by blue light.
If the brain receives a strong brightness signal but no blue signal it should be expected to allocate a colour to that brightness that we might call yellow. This raises the puzzling question as to why we also have a green receptor. There are at least two factors that might explain the apparent redundancy of colour receptors. One is that the central field of vision has few rods so has to work largely on the cones alone. The other is that we also need to make use of the total brightness signal as a way of detecting form through shadow. Maybe if red receptors happened to evolve before blue we would have a different sense of the pure colours.
It is full of murky magical tricks, even if hidden from view. There is also the more general argument, disregarding any suggestion of phenomenal experience, that any sign received from some part of the world will be dependent not just on the causal dispositions of that bit of the world but equally on the disposition of the bit receiving the influence.
Thus an electron is disposed to receive a repulsion signal from another electron but a proton will receive an attractive signal from the same electron. Colour perception is entirely dependent on the dispositions of the receiving apparatus to be influenced by light of different wavelengths. Smell is dependent on the disposition of receptors to be occupied by molecules sniffed in from the world. Two molecules quite different in many respects may smell identical to one animal but quite distinct to another.
Thus it is not possible for us to think of a smell as an inherent property of a substance, independent of who is smelling it. One of the jobs of science is to find a language that can separate these. For simple things like electrons, dispositions can be described simply, in terms of other negatively or positively charged entities.
The disposition takes two forms, repulsion and attraction, manifest as push and pull. However, for a perfume molecule fitting into an olfactory receptor there are millions of possible receptors to interact with and countless possible collating systems that link these receptors to a site where a smell is manifest. Smell is not a concept like negative charge, if anything it is more like push. I have said very little of the historic literature on this topic, which is extensive.
This is largely because these are insights that can and have been reached at many points in history and the historic accounts tend to overburden the topic with misleading jargon. These are properties that objects appear to have in themselves but which Locke realised are more properly seen as ideas raised in the mind by signals coming from the objects.
Although there is a sense in which Locke makes a valid distinction between two categories, I think it is important to note that in a crucial sense his view is misleading because all properties relate to dynamic dispositions to generate manifest ideas. This will be very relevant later but for the time being the key point is that even our sense of space is incommensurable with the space of dynamics. Surely, if we can see at time t by the clock that X matches a two metre ruler, these are established qualities of X, rather than dispositions? However, a careful consideration of the properties that do seem to be dispositional casts doubt on this.
Thus, the properties of being at time t or two metres long can be seen not as additional properties but merely as the spacetime domain within which the dispositional properties we have signs of are operating. Time and space in this sense are the metric of operation of dispositions. To say something is two metres long is to say that a full description of any of the dispositions involved will include that the domain of operation is of two metres length.
If we take dispositions always to be token instances of operation then they do not even exist in the absence of their spacetime domain. An important implication of this is that neither time nor space, as here defined as the metric of causal dispositions, have any appearance. If dispositions have no appearances then their extent cannot have an appearance. This at first seems a truly weird conclusion, but it has to be drawn. And, after all, we could all probably agree that time and space alone do not have appearances.
Not only are the signs of space and time and of colour not like the dispositional events that lead to them, they do not even fall into the same type of general category. Changes and what the changes result in, in the sense of dynamics and manifestations, cannot stand in any sort of analogy to each other. However odd it may seem, this approach does have the great advantage that it relieves us of the burden of trying to work out how the sensed space of the Grand Canyon can exist inside a skull.
It may be worth commenting at this point that the argument just given seems to be extremely difficult for many people to accept and it is uncertain that even some of the greatest minds in the field, like Newton and Russell, really appreciated its full implications. He tells us not to confuse the absolute space and time of physics with the space and time of everyday life. He mentions a number of differences. He contrasts them as absolute and relative, true and apparent, mathematical and common. He seems to be emphasising that they really are different in kind.
Nevertheless, when it comes to his detailed comments it does not seem that he took this difference to be quite as stark as I think one must. He appears to have regarded apparent space and time as merely imprecise, relative versions of the metric of his dynamics. Pace Newton, I think we need to accept that the two senses of space and time are as different as the pattern of moves the pieces in a game of chess make are different from the resulting pattern of pieces on the board - the difference between change and what that change determines.
Russell mentions the difference between the spacetime of physics and the space and time of experience but as for Newton, hints that he sees the difference as one of partial resemblance rather than difference in kind. On the other hand, going back two thousand years, Parmenides and Heraclitus both do seem to have seen just how different change is from manifestation.
My impression is that they may have seen the problem more clearly than Newton. Why is it so difficult for most people to see that these two types of concept are so unlike and related by indirect causation rather than resemblance? The first likely reason is the fact that the dichotomy is usually made invisible by our language.
I hope I have convinced the reader that nothing could be further from the truth. The first word red relates to a completely different kind of concept in these two sentences. It is not that the space of experience does not quite match the space of physics. In the example one sense of space does not match a remembered sense of space, that is all.
The space of physics is part of what is now thought of as a single metric or framework for dynamic causal processes. It is unclear what spacetime could mean other than in the context of something going on. Change is measured in spacetime. In contrast, no dispositions are operating within an experience. No causal relation is going from right to left in my experience of the world. It would not take 0. Even in spatial terms there is no reason to think that a line in my experience is composed of dots.
The space of experience is not a metric of anything. It is not something by which experience is measured because you cannot measure in experiences. Moreover, we experience space and time differently, not as a unified spacetime. There are all sorts of ways of trying to describe the argument in the above paragraph and I know from experience that many people do not follow the argument no matter how one puts it. I am also aware of the extreme fragility of language here.
A subtle shift in the interpretation of any of the words used may indeed render the arguments incoherent and I am very aware that I have taken some liberties so far that will need to be corrected later. Nevertheless, I think that common sense tells us that we have to accept the dynamic spacetime and experienced space and time are completely different kinds of concept for the same reasons as for red and green.
Colours and tastes look to be dispositional. The fundamental properties of physics are also only known to us as dispositions, and are defined as such. Mass is both a tendency to resist acceleration in the face of force and a tendency to attract other masses, or warp spacetime. More esoteric properties of quarks like charm and colour follow the same principle. There are some aspects of the world that I want to save for discussion in later sections because they relate to language and knowledge: like meaning, aboutness as a dream is about a train journey , truth, veridicality and certainty.
Running through all the properties of concrete in the sense of token or instantiated entities that I can think of I cannot find an instance that does not follow the general rule. However, this might of course be because I am missing important exceptions. The more convincing strategy is to see if it even makes sense for features of the world to be non-dispositional.
We need dispositions and we need the experiences they are disposed to determine. If that is not enough then quite what more is wanted? What justification is there for proposing a third category, which so far we have never come across? For this intuition, of there being an additional category of how things are, to be justified, we would have to assume that we are somehow genetically programmed to know that there is a certain way the world is, without ever having had manifest evidence.
Such knowledge would have to be gained without any causal mechanism. The proposal of such a category seems not only unparsimonious but devoid of any motivation. As I shall return to later under a discussion of the logical positivist approach, there is nothing wrong with positing aspects of the universe that at present we have no empirical evidence for. It would be perfectly reasonable to suggest that there are dispositional aspects to elements of the universe like charge, spin, and strangeness but which so far we have no inkling of.
Most physicists believe that indescribable dark matter makes up most of the mass of the universe. It is for this reason that I think we can reasonably suggest that not only all the features of the world that we know, but also all the ones that we might reasonably surmise might exist, are either instances of operation of dispositions or the manifestations those dispositions help to determine. My viewpoint is close to that argued by Shoemaker and is widespread amongst physicists.
Resistance from philosophers seems to be partly a matter of immovable intuition, but some have raised specific objections. CB Martin argues that the suggestion that the only properties things can have are dispositional ones is absurd, based on the argument that you cannot just have a world made up of an endless chain of tendencies or dispositions operating. I very much agree.
Note that this is not a problem of circularity or infinite regress, as some have suggested, but simply that whether you have a single disposition or a chain of dispositions, at some point some disposition has to be a disposition to something. Martin is keen on the idea of casting the causal world in terms of dispositions and manifestations and my choice of the word manifestation may well have been influenced by him.
For Martin, a manifestation is what we might ordinarily call an event. If an egg is a packet of disposition to hatch, then hatching is the manifestation of that disposition. However, all that we can know about hatching is that a certain instance of operation of a disposition has run its course and that subsequently other packets of disposition come into play, like a chick.
Unlike Leibniz, as usually construed, I think we have to say that the universe is not just the continuing harmonious progression of a fixed set of immortal monadic dispositions but that packets can cease to exist and others come into being. We have evidence of some sort of watershed in the history of dispositions we can infer but it is still a history of dispositions leading to dispositions. This history can be considered real in that the dispositions are concrete instances rather than just abstract mathematical structures but it is not clear to me that Martin has got what he wanted which was some sort of end result other than a fabric of dispositions.
To my way of thinking we have not cashed out our dispositions for sure until we have an experience. At least then the buck stops somewhere. Dispositions are not only real in being instantiated but also in that they determine something, and ultimately the only thing we have to be sure about is a manifest experience. It is not legitimate if only because modern physics has shown that deep down the universe does not work like that. However, I do think that there is another potentially legitimate meaning for manifestation: one well worth pursuing.
This makes a manifestation mind-independent but not interaction-independent. Put another way, a manifestation cannot be epiphenomenal, it must have causal power. That seems to make it a disposition, and it does, but it may not make it an instance of change dynamic : more of which later. And I agree with McKitrick that the burden is on those who want the world to be more than a chain of dynamic and manifest dispositions to say what more they want.
McKitrick has argued that if manifestations are dispositions they would be unobservable but I think this can be sorted out when we come to the mechanics of knowing. Although physics says nothing much about manifestation in this broad sense I will argue later that it cannot really do without it.
We want a mind independent reality. However, we cannot ask for an interaction—independent manifest reality, as I shall come to next. Key point: we have no reason to think there are non-dispositional aspects of the outside world. If there were, they would be aspects the like of which nobody has ever encountered.
Martin has a second criticism of Shoemaker, linked to the first. He claims that we know that the world is not just made of dispositions because we are aware of qualitative aspects. This identity thesis has been extended by Heil. There might seem to be a sleight of hand here, and I think there is, but I also think there is mileage in the approach. The problem, I think, lies in ensuring that the right disposition is identified with the right quality.
Words like disposition, manifestation and quality cut the world at certain joints. We need to be sure we are matching the joints up correctly. Yes, we need a qualitative side to our story, but we cannot run together the two meanings.
Table of contents
Qualia are the elements of those manifest ideas, not the qualities that give rise to them. The unification of the two concepts may be desirable, but we need to be careful how we go about it. Martin himself seems to give a clear description of what qualia must be. A smashing of a vase is the interaction of the fragile vase with a rigid hammer. A tasting of pepperiness is the interaction of the pepper with a taste receptor.
A playdough hammer and a sugar taste receptor will not give the same manifestations. But there is a conflation here. Manifestation is being used in two different senses. Out there in the world there are either no qualia or, if one takes a panexperientialist view, which Martin, and certainly Heil seems to resist, there must be two sets, one for the vase experiencing the impact of the hammer and the other for the hammer experiencing the vase in its path. If we take the alternative manifestation of fragility of remaining intact in the absence of impact we seem to have a vase accused of having qualities but not in relation to any occasion out there in the world — we are back to the occasion of experience within the observer and the qualia pattern signifying colours of the ceramic glaze.
Clearly, qualia are manifest. Surely qualities must be the same, unless we are thinking in terms of abstract universals. The wider underlying problem is that if we are to do rigorous metaphysics we cannot expect to make use of everyday objects as examples because these are almost certainly not metaphysical primitives.
In fact, as will be analysed further in section II, we have good reasons for thinking that in the second case the manifestation we recognise as pepperiness does not occur at the taste receptor. However, that will not be the feel we are familiar with, which can only arise after a further chain of interactions in the brain have collated the input from the receptor with many other signals.
What the interaction with the receptor does highlight is that at every step in a causal chain what is passed on is dependent on the fit of the interacting elements, or what one could call the way one is manifest to another. Martin implies that the qualia of experience must be in some way similar to qualities of objects, but there is a crucial difference. Qualia are those aspects, to try and find an appropriate word, of relations between causal dynamic elements in a brain that are experienced by an element S.
Contemporary philosophical jargon makes no reference to such terminology but to my mind that is just too bad for contemporary philosophy. The qualia belonging to S are its autobiography in terms of how it apperceives the world. They are intrinsic to its history but only by dint of relation to other things.
They are what the world is like to S, not what S is like. Qualities seem to be manifest and we think of manifestation as following disposition. The blue quality of the cooker is the blue disposition of the cooker in his terms. It is remarkably hard to sort out the linguistic tangle here, which, again, I think is in large part due to trying to do metaphysics on everyday objects that are not suited to rigorous metaphysical talk.
However, we might also want an equivalent for qualia for mind-independent causal relations. Yet my best attempt to divine what they intend suggests to me an inconsistency in usage of the term. It is quite difficult for me to understand how Russell could have made the mistake I am accusing him of. He argues clearly on so many other issues. Nevertheless, I end up concluding that this is one of those cases where words carry an argument along without actually carrying any valid concepts with them.
This situation is undoubtedly widespread in all our thinking. The reason why I am writing this text at the age of 62 is that it has taken me all that time to disentangle my own confusions over such issues. Russell seemed so well placed to avoid the mistake, but he was as human as any of us and moreover he had immersed himself in a programme of logic that may have emphasised the logical rather than dynamic import of words.
I see this issue as potentially the most crucial tipping point in the development of a comprehensive and coherent complementarity-based world view. Yet there is no coherent causal dynamic account of how it could be otherwise. If we want mind-independent qualities these still have to be interaction-dependent: qualities for partners, just like dispositions for partners.
This might seem to require an unacceptable panexperientialism, but in due course I hope to show that this may not be quite such a bogey as it seems. Key point: everything we know about causal chains indicates that appearances are not carried over from one causal step to another. Thus appearances must arise from the final immediate interaction in a causal chain.
There are several further details and illustrations that I would like to explore in relation to the arguments so far. However, I think it may be helpful to come to what I see as the first main pay-off of these arguments straight away, especially for those readers who may see the arguments as straining the limits of what makes sense and maybe just causing unnecessary mental discomfort.
The first important implication of the complementary view of space, time and everything else is that modern physics need not be seen as posing any special problems about reality. It is not just, as Kant seems to imply, that we cannot know what the real appearance of the world is, in itself and without us watching; there is no reason to think there is one.
If we allow inanimate operational manifestation it will be on the screen, if not the interaction at that point sets up a chain that leads to manifestations in a viewers brain. This issue is not new. Perhaps if children were taught quantum theory at the same age they would be just as happy with it. Another way of putting the point is that change cannot be expected to be just a series of the sort of manifest states that are changing. The flight of an arrow is not just an infinite set of infinitesimally different states of an arrow at a place.
If we run a very fast video camera we might capture ten thousand manifestations but none of these are the change that links them. The motion of the arrow is something else entirely. The impossibility of motion in the outside world being what is manifest to us through our senses may seem strange because we all think we see movement.
However, as I will explore more later, we know enough neurobiology to know that this is not the case. The multiple meanings of words make it very difficult to be sure that one can convey these ideas effectively in a brief summary like this, but hopefully in the context of the whole text it will be clear. There is also the potentially confusing fact that in physics momentum can be manifest, but in a context not relevant to our sense of movement. A wave function does not tell us that there is a particle here, or there, and it certainly does not tell us that the particle is both here and there.
It says that the dynamic disposition that leads to the manifestation, that is particle-like in the sense of being at one location, is spread out. As I understand it, this way of looking at quantum theory also makes sense of the meaning of the variables given in the wave function. They seemed to refer to the probabilities that the entity would be observed to have such features.
But physicists should have expected this since the wave function is an account of the dynamics and dynamics is a matter of tendency or disposition — of what result is likely to be obtained. In previous theories of physics the dispositions were generally described in terms that assumed infinite divisibility. This meant that there could always be a definite answer to a question about what was expected.
A disposition might predict a value of 0. However, once a physical theory has built in to it the idea that all manifestations have a finite grain then there can only be probabilities. The probabilistic nature of quantum theory should have been quite unsurprising.