The Actual Colour of the Sun

‘The sun is actually white, it just appears yellow to us through the Earth’s atmosphere.’

This is a line that appeared on Facebook a while ago, courtesy of my friend Else Cederborg, who posts all sorts of curious and interesting things.

It is a common form of argument that most will readily understand and generally accept without thinking too hard about it. Yet the sun is not actually white, nor does it just appear yellow, facts you can easily check for yourself.

Depending on the time of day and the atmospheric conditions, the sun is variously deep blood red, orange, dusky pink and (behind a veil of mist or thin cloud) a sort of milky white; much of the time it has an incandescent brilliance which can hardly be called a colour since we cannot bear to look at it directly. Though it may appear yellow, the usual place to encounter a yellow sun is in a representation of it: a child’s drawing, for instance (against a blue sky above the square white house, surrounded by green grass, with its four four-paned windows and red triangular roof with single chimney belching smoke) or else in the icons used in weather forecasting.

How we come to accept an argument that runs counter to all experience, and perversely insists on a condition for actuality (being seen outside the Earth’s atmosphere) which few of us will ever experience, is a case worth examining.

At the heart of it is that curious human thing, a convention (I say ‘human’ though it might be that other creatures have conventions, but that is for another time). A convention, effectively, is an agreement to treat things as other than they are – it is a form of pretence. This definition might seem surprising, since what is usually emphasised in conventions is their arbitrary character – the typical example being which side of the road we drive on, which varies from country to country.

However, what makes the rule of the road a convention is that we endow it with force, a force that it does not actually have: we say that you must drive on the left (or the right); that you have to – even though any one of us can show this not to be the case. Of course, if you engage in such a demonstration, you might find yourself liable to a range of legal sanctions, or worse still, involved in an accident. The fact that the rule has to be backed by force proves that it has no intrinsic force; on the other hand, the risk of accident shows that the pretence is no mere whim, but sound common sense: conventions are there because they are useful.

A great deal of human behaviour is conventional if you look at it closely: things are deemed to be the case which are not, actually (international borders is a good example – again, these are arbitrary, but it is the power with which they are endowed that makes them conventions). In this regard, it is worth recalling a remark that Wittgenstein makes somewhere (Philosophical Investigations, I think) to the effect that ‘explanation has to come to an end somewhere’. In other words, despite what we tell children, ‘just because’ is an answer. Conventions are so because we say they are so.

So what colour is the sun?

That takes us to the boldest and most fundamental of conventions, the one that underpins our standard way of thinking about the world, for which we have Plato to thank. Plato insists at the outset on discrediting the senses, saying that they deceive us, giving us Appearance only, not Reality.

This is a move of breathtaking boldness, since effectively it dismisses all experience as ‘unreal’ – as a starting position for philosophy, it ought to be quite hopeless, since if we cannot draw on experience, where are we to begin? If reality is not what we actually experience, then what can it be?

However, there is a different angle we can consider this from, which makes it easier to understand how it has come to be almost universally adopted. What Plato is proposing (though he does not see this himself) is that we should view the world in general terms: that we should not allow ourselves to be distracted by the individual and particular, but should see things as multiple instances of a single Idea or Form; or, as Aristotle develops it, as members of a class which can be put under a single general heading: trees, flowers, cats, horses, at one level, plants and quadrupeds at another, and so on.

Implied in this is the elimination of the subject: the world is not as it appears to me or to you or to any particular individual (since particular individuals exist only at the specific level) the world is to be considered as objective, as it is ‘in itself’, i.e. as a general arrangement that exists independently of any observation.

This is a very useful way of looking at things even though it involves a contradiction. Its utility is demonstrated by the extraordinary progress we have made in the 2.500 years or so since we invented it. It is the basis of science and the foundation of our systems of law and education.

Effectively, it starts by accepting the necessary plurality of subjective experience: we see things differently at different times – the sun is sometimes red, sometimes pink, sometimes incandescent; different people have different experiences: one man’s meat is another man’s poison. In the event of dispute, who is to have priority? That problem looks insoluble (though the extent to which it is an actual problem might be questioned).

So, we must set subjective experience and all that goes with it to one side, and rule it out as the basis of argument. Instead, we must suppose that the world has a form that exists independently of us and is not influenced by our subjective observation: we posit a state of ‘how things actually are in themselves’ which is necessarily the same and unchanging, and so is the same for everyone regardless of how it might appear.

This is how we arrive at the position stated at the outset, that the sun is ‘actually’ white, and that its ‘actual state’ should be taken as ‘how it appears from space,’ even though we live on earth and seldom leave it.

There is a confusion here, which has surfaced from time to time in the history of philosophy since Plato’s day. The strict Platonist would dismiss the whole question of the sun’s true colour in terms akin to Dr Johnson’s, on being asked which of two inferior poets (Derrick or Smart) was the greater: ‘Sir, there is no settling the point of precedency between a louse and a flea.’ Colour belongs to the world of Appearance, not the world of Forms or Ideas.

However, as the insertion of the argument about the earth’s atmosphere shows, we feel the need of a reason to dismiss the evidence of our own eyes (and this is where that little sleight-of-mind about ‘just appearing yellow’ comes in – so that we are not tempted to look too closely at the sun as it actually appears, we are fobbed off with a conventional representation of it that we have been accepting since childhood). The argument is that the atmosphere acts as a filter, much as if we looked at a white rose through coloured glass and variously made it appear green or red or blue: so just as we agree the rose is ‘actually’ white, so too the sun’s ‘actual’ colour must be as it appears unfiltered.

This, however, is specious. Leaving aside the fact that the rose is certainly not white (as you will soon discover if you try to paint a picture of it) at least our choice of default colour can be justified by adding ‘under normal conditions of light’ which most people will accept; but ‘as it appears outside the earth’s atmosphere’ can hardly be called ‘normal conditions of light.’

What has happened here is that the subjective ‘filter’ which Plato wished to circumvent by eliminating the subject – ‘let us ignore the fact that someone is looking, and consider only what he sees’ – has reappeared as an actual filter, so that the whole appearance/reality division has been inserted into the objective world by an odd sort of reverse metaphor. The need to give priority to one of the many possible states of the sun is still felt, and it is solved by arbitrarily selecting ‘the sun as it appears from space’ as its actual state, because that seems logical (though in fact it is not).

The subjectivity of colour in particular, and the subject-dependence of all perception in general, is like a submerged reef that appears at various periods in the sea of philosophy. Locke is troubled by colour, which he wants to class as a ‘secondary quality’ since it evidently does not inhere in the object, as he supposes the primary qualities – solidity, extension, motion, number and figure – to do. Colour is ranked with taste, smell and sound as secondary, which is just a restatement of Plato’s rejection of the senses in other terms.

Berkeley, however, sees that this is a specious distinction and gets to the heart of the matter with his axiom esse est percipi – ‘to be is to be perceived’. Everything we know requires some mind to perceive it: a point of view is implicit in every account we give. There can be no objective reality independent of a subject (as the terms themselves imply, since each is defined in terms of the other).

The response to this is illuminating. Berkeley’s dictum is rightly seen as fatal to the notion of an objectively real world, but instead of accepting this and downgrading Plato’s vision to a conventional and partial account employed for practical purposes, every effort is made to preserve it as the sole account of how things are, the one true reality.

Berkeley’s own position is to suppose that only ideas in minds exist, but that everything exists as an idea in the mind of God, so there is a reality independent of our minds, though not of God’s (a neat marriage of philosophy and orthodox christianity – Berkeley did become a bishop in later life. The Californian university town is named after him).

Kant’s solution is to assert that there is an independent reality – the ding-an-sich, or ‘thing-in-itself’ but logically it must be inaccessible to us: we know it is there (presumably as an article of faith) but we cannot know what it is like.

Schopenhauer’s solution is the most ingenious, and to my mind the most satisfying. He agrees that we cannot know the ding-an-sich as a general rule, but there is one notable exception: ourselves. We are objects in the world and so are known like everything else, via the senses – this is Plato’s world of Appearance, which for Schopenhauer is the World as Representation (since it is re-presented to our minds via our senses). But because we are conscious and capable of reflecting, we are also aware of ourselves as subjects – not via the senses (that would make us objects) but directly, by being us. (To put it in terms of pronouns: you know me and I know you, but I am I; I am ‘me’ to you (and in the mirror) but I am ‘I’ to myself)

And what we are aware of, Schopenhauer says, is our Will; or rather, that our inner nature, as it were, is will: the will to exist, the urge to be, and that this is the inner nature of all things – the elusive ding-an-sich: they are all objective manifestations of a single all-pervasive Will (which happens in us uniquely to have come to consciousness).

This idea is not original to Schopenhauer but is borrowed from Eastern, specifically Hindu and Buddhist philosophy, which belongs to a separate (and possibly earlier) tradition than Platonic thought does (it is interesting to note that a very similar way of looking at things has been likewise borrowed by evolutionary biologists, such as Richard Dawkins, with the notion of ‘the selfish gene’ taking the place of Schopenhauer’s ‘Will’ as the blind and indifferent driving force behind all life).

I find Schopenhauer’s account satisfactory (though not wholly so) because it is a genuine attempt to give an account of the World as we experience it, one that reconciles all its elements (chiefly us as subjects with our objective perceptions) rather than the conventional account of Plato (and all who have followed him) which proceeds by simply discounting the subject altogether, effectively dismissing personal experience and reducing us to passive observers. Although the utility of this convention cannot be denied (in certain directions, at any rate) its inherent limitations make it inadequate to consider many of the matters that trouble us most deeply, such as those that find expression in religion and art; and if, like those who wish to tell us that the sun is ‘actually’ white, we mistake the conventional account for an actual description of reality*, we end up by dismissing the things that trouble us most deeply as ‘merely subjective’ and ‘not real’ – which is deleterious, since they continue to trouble us deeply, but that trouble has now been reclassified as an imaginary ailment.

*perhaps I should say ‘the world’ or ‘what there is’. There is a difficulty with ‘reality’ and ‘real’ since they are prejudiced in favour of the convention of an objective world: this becomes clearer when you consider that they could be translated as ‘thingness’ and ‘thing-like’. The paradigm for ‘reality’ then becomes the stone that Dr Johnson kicked with such force that he rebounded from it, i.e. any object in the world, so that the subject and the subjective aspect of experience is already excluded.

Vanishing Point and the Golden Rule (by way of Immanuel Kant)

I remember once becoming absurdly excited in Princes St. Gardens in Edinburgh – that was just where I chanced to be, not the cause of the excitement – when I realised that an interesting thing happens if you number the dimensions in the reverse of the conventional order.

My brother had once explained the concept of the fourth dimension to me by saying that it was ‘at right-angles to the third’ which he elucidated by explaining that, as a point drawn out in one direction gives a line, so that line, moved at right angles to itself, generates a plane surface, which in turn generates a volume when moved at right angles to itself; hence the next dimension, the fourth, must involve performing an identical operation with a cube.

This I found pleasantly bamboozling: I could follow the first three steps of the procedure perfectly, yet with the fourth there seemed nowhere left to go; yet I convinced myself that dwellers in a linear or planar universe would experience the same difficulty at stages two and three. Later, when the same brother suggested that the fourth dimension was Time, I formed some notion of a cube moving through space and leaving a sort of cubic trail behind it – which was the direction I was headed in when I started thinking about Duchamp’s Nude Descending a Staircase, here . There is a similar though less marked suggestion of movement in time in this picture, where Miss Kate Ward has admirably captured the headlong speed of my Dursley-Pedersen:

Dursley-Pedersen at speed

John Ward at speed on his Dursley Pedersen, photographed by his daughter Kate

But in Princes Street Gardens it struck me that if we begin with volume as the first dimension – and picture a cube, say – we can abstract a second dimension from that by attending to one of its surfaces and ignoring the rest; then by the same method, we can consider the edge of that surface in isolation to give us a line – from where, if we wish, we can go to its end, and arrive at a point – but that is, indeed, the end, and there is literally no point in going beyond it.

I still consider that a neat manoeuvre, though nowadays I am more interested in the point you end up with than in the doing away with the need for any further dimensions.

Duchamp’s nude shows a temporal sequence as a spatial one, and that is consistent with our normal usage, which is to talk about time in spatial terms – we speak of a length of time, a short time, a space of time and so on, and we use ‘before’ and ‘after’ – which denote spatial relations – to speak of temporal ones.

It is clear that the ideas of space, time and movement are bound together: indeed we use movement through space (which takes time) as a way of thinking about time, even where no movement through space is involved – and since we developed film technology, we have reinforced this with time-lapse photography, so that we see flowers opening and closing, buildings being erected, even carcases decaying – though in fact there is movement there, without change of location, though it is normally too slow for us to perceive as such – we only notice that there has been a significant change from an earlier state to a later one, without detecting it from moment to moment.

But could you arrive at the notion of movement (and so of time) in a world of immutable Forms, such as Plato envisages in his Republic? The Forms are timeless and unchanging, but if they are distinct and separate (and extended, for how else could we picture them?) it would seem that they must occupy space and there must be distance between them; and where there is distance, there is surely the possibility of movement, and so of time, even if there is none actually?

However, we have introduced another element here, the one that Berkeley drew to our attention: a perceiver. To picture a world of timeless forms is to do so from some point of view, a particular location within that world, and it would seem to be from there that the notion of movement arises – and indeed, might we go further and suggest that it is location that gives rise to the concept of space?

Does a point imply space? in other words, is even a point – location without extension – sufficient to require the whole of infinite space for it to be located in, or is that just a product of our thinking being tied to a three-dimensional model to start with?

But there is some sleight-of-mind here: we might picture a point in space from which we look outward, and so gain some sense of depth and distance, but in what direction are we looking? more to the point, what are we looking with? It seems we have smuggled in an eye, albeit an invisible one – though you might well ask how you can have an eye without a lens, an iris, an optic nerve – and some sort perceptive apparatus at the other end of that nerve.

This leads me to Kant, and his observation that ‘space, time and causality are the mode and manner of our perception.’ Hume – whom Kant spoke of as having roused him from his dogmatic slumber – had suggested that the only way we could arrive at an idea of causality was through observing invariable succession – we see that A is invariably followed by B and in time conclude that A causes B. This is not a very satisfactory account, and it is thoroughly demolished by Schopenhauer, who points out that the most familiar and invariable succession of night and day does not lead us to suppose that one causes the other.

It is, however, the best you can do if you want to insist – as Hume did – on the empirical principle, i.e. that all knowledge is derived from experience, via the senses. What Hume failed to grasp, as Schopenhauer pointed out, is that perception is an intellectual act, not the passive process Hume supposed it to be – the mind works on and arranges the data supplied by the senses – in fact it makes sense of them.

The stepping stone between Hume and Schopenhauer is Kant, who realised that causality was not something we derived from experience, but rather a pre-requisite for making sense of it – it is, if you like, part of our intellectual apparatus; and it is not alone – he couples it with Time and Space, grouping all three together as ‘the mode and manner of our perception’ and putting forward the notion that, far from being derived from experience, these three are the means by which we make sense of experience itself. In this, they have been likened to a set of spectacles that we cannot remove, even when we realise that they  condition all that we see. We are therefore in the frustrating position of knowing that the world as we know it exists only for us (or those similarly equipped) which is the truth that Berkeley realised with his esse est percipi ; what the world is actually like in itself (i.e. unconditioned by the apparatus of space, time and causality) we cannot imagine.

This is what started, like a hare from its form, the ding-an-sich or thing-in-itself which Schopenhauer eventually ran to ground (with the aid of oriental philosophy). Schopenhauer’s brilliant move is to point out that, while the world as it is known to us via the senses is indeed much as Kant suggests, a world of representation, of objects-for-the-subject, conditioned by our intellectual apparatus, that is not the sole aspect we have access to – if we turn our eyes inward, as it were, we become aware that there is, in ourselves, a sort of privileged glimpse of the inner nature of the world, the very thing-in-itself – namely, the Will.

For Schopenhauer, we as individuals are self-conscious outposts of a single and otherwise blind and unconscious Will which is manifested everywhere and in everything and whose sole aim is to exist. This has echoes in our own day in the ideas of the evolutionary biologists, that we are in effect the mere by-product of our genes’ determination to reproduce ad infinitum. It is not of course original to Schopenhauer, who derived it from his reading of ancient Eastern, particularly Indian, philosophy.

Schopenhauer draws pessimistic conclusions from this: effectively, all that self-consciousness has done is make us helpless spectators, aware that we are embodiments of a will that we cannot control but which rather drives us: all we can do, at best, is to quiet the will, to turn away from existence (though Arthur himself was happy to keep going to what was then the ripe old age of 72). Nietzsche, who saw himself as a disciple of Schopenhauer, takes the idea in a more sinister direction: we can embrace our situation, and recognise that the will takes us beyond good and evil – if we are strong, we should follow its promptings wherever it leads us and glory in it, rejecting the ‘slave mentality’ of judaeo-christian thought, which he saw as essentially a conspiracy of the weak to keep power from the strong. You do not need to go far beyond Nietzsche (he died, insane, in 1900) to find the horrors to which that ultimately led.

Yet this interpretation seems to turn on a needlessly pessimistic interpretation of the nature of the Will coupled to an erroneous aggrandisement of our own status – both Schopenhauer and Nietzsche assume that, in coming to consciousness in Man, the Will has attained its highest form of existence (though Nietzsche might qualify that by adding ‘so far’). However, if we look more closely at the judaeo-christian tradition which Nietzsche dismisses and at the Eastern thought that Schopenhauer derived his ideas from, we find a different way of looking at it – having looked into ourselves, and seen that we are embodiments of a single will (and might that will not be higher, rather than lower, and ourselves just waking into it, not yet fully comprehending it?) we can then look outwards again and see others not as different from ourselves but essentially the same – which is the foundation of compassion and the Golden Rule which characterises all the great belief systems – ‘treat others as you would have them treat you’ – or, if you prefer, love your neighbour as yourself  – (because that is what, in effect, he is). (For an excellent and inspiring 10’ talk on the Golden rule, click here. )

‘we are only doing philosophy’

Esse est percipi – to be is to be perceived. That is Berkeley’s great insight, that the world as we know it exists only for us and beings similarly equipped. It is an observation widely misunderstood because the truth of it is difficult to express, hence the famous exchange between my countryman Boswell (whom I could never take to) and Dr Johnson (whom I much admire):

After we came out of the church, we stood talking for some time together of Bishop Berkeley’s ingenious sophistry to prove the nonexistence of matter, and that every thing in the universe is merely ideal. I observed, that though we are satisfied his doctrine is not true, it is impossible to refute it. I never shall forget the alacrity with which Johnson answered, striking his foot with mighty force against a large stone, till he rebounded from it — “I refute it thus.”

This is typically tendentious from Boswell, who has plainly made up his mind – ‘ingenious sophistry’ ‘merely ideal’ and ‘we are satisfied [by what means, one may ask?] his doctrine is not true’ and of course Johnson’s response proves only that he had no more idea than Boswell did what Berkeley was talking about.

The good Doctor’s error is excusable, however, since the problem lies with language and what happens to it when we start to use it for philosophy: words are twisted out of their usual meaning, pushed to their limit till they crack. This must happen, since philosophy is about clarifying our ideas, which in turn involves trying to clarify the language in which we express them – when I was young, I used to think that language could be ‘improved’ and ‘purified’ by philosophy, so making it a fitter vehicle for thought, but now I see that the very murkiness of language, its openness to a range of meanings, its vagueness and ambiguity, are strengths rather than weaknesses.

(Wittgenstein was aware of how odd philosophical discussion could seem to the outsider:

I am sitting with a philosopher in the garden; he says again and again “I know that’s a tree”, pointing to a tree that is near us. Someone else arrives and hears this, and I tell him: “This fellow isn’t insane. We are only doing philosophy.” (On Certainty, 467))

Johnson’s error is repeated by those who think that what Berkeley is saying is that when you leave a room, all the furniture ceases to exist. This seems absurd and impossible to them because they continue to imagine the room, but see it as suddenly empty when the person leaves – something you might illustrate amusingly in an animated film, maybe. ‘But how can the furniture disappear from the room?’ they demand. But the furniture doesn’t disappear from the room: the room is as much dependent on our perception as what is in it. In one sense, Berkeley is saying something we all believe but find unremarkable: you can only see a thing when you’re looking at it.

When you put that in the passive – ‘a thing can only be seen when there is an observer’ you edge towards the real truth of Berkeley’s insight, which is that there is an element in all our observations which we take for granted, namely the observer. You cannot think yourself out of the picture: if you assert, ‘but I know perfectly well what my room looks like when I’m not there – I can picture it now’ then all you are saying is ‘I can imagine what it looks like when I am there.’

A modern-day Johnson might rig a camera with an automatic switch and triumphantly flourish the resultant picture of an empty room, complete with furnishings, exactly as we would expect, saying ‘I refute it thus!’ But to get at what Berkeley meant, you must try to imagine the room (or anything at all) as it appears from no particular point of view. It is impossible, of course, though you might have fun trying to simulate it with a battery of cameras in the same way that a single camera simulates our being in the room when we aren’t. The resultant picture would be a curious one: you would have a simultaneous view of the room and its contents from all four, or rather all six, sides. Perhaps the nearest thing to it might be a cubist painting, such as Georges Braque’s Violin and Candlestick:

Violin-and-Candlestick-1910-Oil-on-canvas

Another way of coming at this is to imagine some improvement in the eye, so that our visual spectrum is extended – things that presently seem to us empty space would perhaps be intriguingly shaded and coloured, as described by Old Mathers in Flann O’Brien’s The Third Policeman:

There are four winds and eight sub-winds, each with its own colour. The wind from the east is a deep purple, from the south a fine shining silver. the north wind is a hard black and the west is amber. People in the old days had the power of perceiving these colours and could spend a day sitting quietly on a hillside watching the beauty of the winds, their fall and rise and changing hues, the magic of neighbouring winds when they are inter-weaved like ribbons at a wedding. It was a better occupation than gazing at newspapers. The sub-winds had colours of indescribable delicacy, a reddish-yellow halfway between silver and purple, a greyish-green that was equally related to black and brown. What could be more exquisite than a countryside swept lightly by cool rain reddened by the south-west breeze?

The thing that Berkeley wants us to grasp is that if you think yourself out of the picture, it ceases to be a picture: it is no longer seen from any particular viewpoint, there is no cunning apparatus, be it eye or camera, to detect the visible spectrum of light and give objects in the room shape and colour; if the bonsai tree on the desk keels over, there is no ear to convert the compressions and rarefactions of the air that result into sound; without a nose, the pungent aroma of yesterday’s kipper is no more than particles in the atmosphere.

Picture this: the last man in the world and his dog are gazing out through a triple-glazed window at some apocalyptic scene – meteorites raining down on the earth, perhaps. The last man keels over and dies; since his dog sees in black and white (though he inhabits a rich world of scent and sound of which his late master was almost wholly ignorant) has all colour now gone out of the world?

Put this way, it sounds like something amazing (again, we could illustrate it in animation – as the man is dying, the colours slowly fade to sepia) but that is because of what we have chosen to focus on: say instead that when the last man dies, the world as we have known it dies with him – that brings home to us how much more there is to our world than just the single element of colour: there is memory, emotion, the record of all that small section of sensory data which we are equipped to process, together with the feelings it evokes, the ideas it gives us, the art and poetry and music it inspired, the stories we told about it and our interaction with it; none of this exists in its familiar form without us: when we are gone, it is gone too (and even the books we leave cease to be books with none to read them).

And that, if you think about it, is the other side of the Jewish teaching (Talmud, Sanhedrin 37a) commonly rendered in English ‘who saves one life, saves the world entire.’ (It is interesting to find that this is the lesson drawn from the tale of Adam’s creation in Genesis, rather than any suggestion that it is some sort of rival to Darwin’s Theory of Evolution: the value of stories is that they teach us how to live in the world).