Entropy
From thermodynamics to therapy: how a concept from physics can tell us something about rigidity.
Entropy is, in our impression, one of the most beautiful concepts in physics, and at the same time one of the concepts most often applied in confusing ways. Broadly speaking, it refers to the degree of unpredictability or disorder in a system.
In thermodynamics, entropy is a measure of the number of microscopically different states a system can be in, given what we observe macroscopically. A cup of scalding hot coffee and a cup of ice-cold coffee differ considerably at the macro level, but the hot coffee has many more microscopic configurations that correspond to that same temperature. High entropy thus means: many possibilities, much movement, little structure.
The second law and the direction of time
According to the second law of thermodynamics, the entropy of an isolated system does not decrease over time. A student's room becomes untidy of its own accord and does not tidy itself, a cup of coffee cools, ice cubes melt. This is also why we can read the passage of time from such processes.
How is it, then, that in open systems, such as a living being, an ecosystem or a person, we nevertheless see ordered structures? Open systems take in energy from outside (food, sunlight, warmth) and can thereby lower entropy locally, at the cost of an increase elsewhere. Living systems "fight" the second law in this sense, as Ilya Prigogine put it, and the effort this takes is what we call life.
Entropy in psychological time series
In psychological data the concept is used in its own way. There it often concerns sample entropy or permutation entropy: measures of the predictability of a time series. A patient whose mood follows exactly the same course every day has low entropy in her mood. A patient who shows different patterns every day has high entropy.
"In clinical practice, both too much and too little entropy seem problematic. Too much: chaos and instability. Too little: rigidity and stuck patterns."
This is an important nuance. A healthy system seems to have a moderate entropy: enough variation to adapt to changing circumstances, and enough stability to remain recognisably itself. Entropy that is too low can be seen, for example, in depression (everything feels the same, behaviour has rusted in place), in obsessive patterns and in some forms of trauma. Entropy that is too high can be seen in some forms of anxiety, in dissociation and in acute crises.
What this means in practice
In our view, the usefulness of entropy as a concept lies less in precise measurement (which is methodologically difficult) than in the way of looking it makes possible. A patient who says "it is always the same" is describing a system with too low an entropy. A patient who does not know who she will be tomorrow is describing a system with too high an entropy. In both cases, restoring a healthy middle position, flexible but not rudderless, can be a meaningful treatment goal.
Schiepek has included entropy measures as one of the indicators in his Synergetic Navigation System. In his work, a marked drop in entropy can be an early warning signal of an approaching phase transition in the therapeutic process, for better or for worse.