The Holi photograph and the idea of entropy
A photograph of a crowd, and how one may recognise in it the idea of entropy — without drowning in formulas.
A photograph of a Holi festival in India: hundreds, perhaps thousands of people, all painted with coloured powder, all in motion, without visible structure. At first sight: chaos. On closer view: much order, but of a kind we do not commonly recognise.
Such an image brings to mind the notion of entropy — a term from physics not seldom misunderstood in mental health care. It is no synonym for "chaos" or "disorder", though it is sometimes used as such. It refers to something more precise, and it is worth pausing on.
What is entropy roughly?
Entropy, as Boltzmann defined it in the nineteenth century, is a measure of the number of possible ways in which a system can be in a given state. That sounds abstract; an example may help.
Suppose: you have a box with twenty numbered balls. You throw them about. The state "all twenty balls lie in order, with number 1 in the upper-left corner" can be realised in precisely one way. The state "balls lie disordered in the box" can be realised in very many ways — billions of combinations that look about equally messy to you.
The ordered state has low entropy: one way. The disordered state has high entropy: very many ways. When you shake the box, you almost always shift towards the high-entropy state — not because nature "wants disorder", but simply because there are far more messy configurations than tidy ones.
The Holi photograph
Back to the crowd. Hundreds of people, all in motion, colourful and spontaneous. That state can be reached in very many ways — a random change of who stands where hardly alters it. High entropy.
Compare that with a military parade: the same people, but now in tight rows, all in the same posture. That state can actually be realised in only one way — a minute shift and it looks at once different. Low entropy.
Both have order. Both have structure. But the order is of a different kind. The one is an order of pattern, the other an order of freedom.
What this has to do with mental health care
In complexity science, entropy is used to say something about how rich and flexible a system is. A healthy human system seems to know a certain measure of entropy in its daily functioning — flexibility, variation, room for change. Not every day is the same, not every hour identical.
Some psychiatric pictures seem to be accompanied by a decrease in that entropy. The system becomes more rigid, more predictable, less rich in its variation. In severe depression a person often walks in fixed patterns, with days resembling each other and emotions presenting themselves in fixed forms. The entropy of the system then seems to have dropped.
Other pictures seem rather to be accompanied by too much entropy. In severe dissociation or psychosis the system can become so incoherent that hardly any repeatable pattern is to be found. There entropy seems unhealthily high.
Health seems to lie somewhere in between: enough structure to be recognisable, enough freedom to be able to move.
A modest conclusion
The concept of entropy, despite its origin in thermodynamics, seems clinically useful — provided it is used with care. Not to explain everything, but to make formulable questions otherwise hard to pose. Does a patient have enough dynamical room in her daily functioning? Or is she on too narrow a path? Or has her life become so incoherent that no recognisable pattern remains?
The Holi photograph recalls that order does not always coincide with strictness. Sometimes a rich, broad, colourful mobility is the healthiest form of order that can present itself. And when that mobility decreases — or, conversely, breaks through — there is, perhaps, something to discuss.