Signs, symptoms, symbols, markers: all act as guides in a complex world. They are used in overlapping ways but I shall suggest what I think are their main uses or meanings. A few of them have medical uses and they are the easiest to make precise, or at least to make their use in medicine roughly clear.
'Symptoms' are what we experience as patients. For example, we might report to our GP (assuming the unlikely situation that we are ever allowed to see our GP again) that we feel shivery, nauseous, with a persistent cough and sore in the joints. In other words, symptoms are what patients experience. A GP, on the other hand, might examine us for signs of this or that ailment. For example, blood pressure or the analysis of blood or urine could provide signs of this or that ailment.
A 'marker' would be a trait or condition which indicates a pre-disposition for some disorder. For example, a persistently raised cholesterol level might be a marker for a future heart condition. No doubt those more expert than I am in medical terminology might be able to distinguish between a marker and a risk-factor. But I will not go there.
The terminology of signs is used in many contexts. For example, clouds are signs of the likelihood of rain. Signs in this sense are evidence from which we can infer future events. We can all read some natural signs, but others require experts in assorted spheres. Vulcanologists, for example, can read the signs that a volcano is likely to erupt and meteorologists have a pretty accurate idea of an approaching hurricane. Wise sayings about a red sky at night being a shepherd's delight are nowadays replaced by the use of weather satellites and computer modelling.
Expertise in the reading of natural signs is obviously important in helping to keep us safe. More mundanely, we use them all the time as guides on what to wear and how to go about our daily lives. Shakespeare sometimes uses the term 'portent' to refer to natural signs which indicate possible disaster.
But signs can also have their meaning established by convention. One type of convention is that the sign should in some way resemble what it is a sign of. For example, a sign of workmen with shovels is sometimes used as a sign of roadworks ahead, or a picture of an aircraft is a sign that there may be low-flying aircraft around. As a driver, I am not sure what I am meant to do about that one. A picture of sardines on a tin is a sign that unsurprisingly there are sardines in the tin.
Other conventional signs are entirely arbitrary. For example, there is a widespread convention that a red light is a sign that we should stop. It is a clear sign but entirely established by convention. Learner drivers are nowadays faced with an actual examination on their knowledge of the increasing number of road signs.
When we move to symbols, we reach an area of enormous complexity. Indeed, there is an entire branch of academic study – semiotics – devoted to the study of symbols. Symbols can have powerful cultural significance. For example, flags are symbols of a nation. If you don't like the nation, you can burn its flag. But symbols are common in less emotionally-charged contexts, such as cartography. For example, the symbol 'P' on a map is likely to be a symbol for a car park, or a tent might indicate a camping area. Maps often provide a key to the meaning of their symbols, not all of which are obvious.
Human behaviour can have symbolic meaning. For example, the wearing of black or subdued colours at a funeral is a symbol of respect for the deceased or the relatives, although perhaps the symbolic value of that is fading as dress conventions change. I remember that at board meetings of Glasgow University Union the members had to wear jacket and tie. This was a symbol that the members of the board were acting responsibly with the large sums of money they controlled.
In general, we can say that symbols enable us to go beyond what is immediately before us and create linkages between very different situations, or concepts. Most obviously, words are symbols which enable us to express ideas and beliefs. Words as symbols take us beyond our immediate experience and enable us to make sense of the world. Whereas the symbolic meaning of some words is clear and unambiguous, in other cases the meaning has much more resonance. For example, the symbolic value of 'The cat sat on the mat' is clear and unambiguous; there are no deeper resonances.
Coleridge draws a distinction between images of the fancy and images of the imagination. Images of the fancy can be ingenious, apt, amusing and can suggest a new way of looking at something. Popular songs sometimes do this: 'You're the cream on my coffee' – an affectionate image of the fancy. But contrast the limited symbolic value of that image of the fancy with the resonance at the end of Dylan Thomas's poem Fern Hill
Oh as I was young and easy in the mercy of his means,
Time held me green and dying
Though I sang in my chains like the sea.
The symbolic meaning of several of the words and their combinations make continuing ripples in our consciousness or indeed our subconscious minds. The symbols have a complexity which cannot be made definite and cannot be pinned down; they continue to resonate.
A specific symbolist movement in poetry developed in France towards the end of the 19th century. A central figure in this movement was the French poet Stephane Mallarme (1842-98). The movement was a reaction against 'realist' or 'naturalist' tendencies in literature. They saw the symbol as a means of evoking moods or of suggesting ways into a spiritual world, sometimes by means of the musical properties of language.
The symbolist movement in literature was paralleled by a similar movement in the visual arts. Just as symbolist poets regarded poetry as a means to provide a symbolic expression of inner life, so too the artists stressed the mystical and dreamlike. Their influence can be seen for example in the Pre-Raphaelites, or in Debussy's opera Pelleas et Melisande
Symbolism can be found in music much earlier than the French symbolist movement. The music of J S Bach is full of it. For example, the Crucifixus
in his Mass in B minor
is written over a descending ground bass in E minor which takes us to a very dark place. But in its last few bars, which are to be sung as quietly as possible, there is a magical modulation into the relative major. In other words, in the final darkest moments there is a symbol of hope – confirmed by the glorious burst of positive sound in the Et Resurrexit
. Believers and non-believers alike admit to being uplifted by this life-affirming musical symbolism.
More down to earth, we are familiar with the symbolism of flowers – the red rose is the obvious one. But the symbolism of the perfect rose does not satisfy everyone, and certainly not Dorothy Parker in her poem of 1937:
Why is it no-one ever sent me yet
One perfect limousine, do you suppose?
Ah no, it's always just my luck to get
One perfect rose.
Robin Downie is Emeritus Professor of Moral Philosophy at the University of Glasgow