The Field

Physiotherapy and the Planetary Ecology of Movement

In the first post of this series, we explored Thomas Nail’s concept of flow, the continuous circulation of matter and energy through all things. In the second, we turned to the fold, the way this movement loops back on itself, producing relatively stable yet dynamic patterns. We saw that bodies, including human bodies, are not static substances but metastable configurations of motion, rhythmic persistence rather than fixed form.

In this final post, we turn to the field. If the flow is the continuous movement of matter, and the fold its local inflection, the field is the wider distribution of many folds in relation. For Nail, a field is “a metastable distribution of periodic cycles”. As matter flows and folds, it also creates “metastable feedback patterns that can sustain and reproduce themselves” (Nail, 2021, p. 42). A field is not a ‘thing’ or a container that holds objects. It is the emergent order itself, the pattern by which folds circulate, knot together, and enable persistence.

A river basin is a field. A galaxy is a field. And I will argue here, so too is health.

We Have Always Been Planetary

One of the more striking implications of Nail’s kinetic philosophy is the collapse of the boundary between organism and planet. If bodies are folds in a continuous fabric of motion, then they are not separate from the material processes of the earth. They are entangled expressions of them.

Nail writes that “nature and humans have never been separate systems” (Nail, 2021, p. 2). The iron in our blood was forged from stardust. The calcium in our bones cycled through ancient marine organisms and geological strata before arriving in us. The oxygen we breathe is an atmospheric fold produced and reproduced by photosynthetic processes stretching back billions of years. As Nail puts it, “the earth is not simply among the stars, it is of the stars” (Nail, 2021, p. 44). Our bodies are, in the most literal sense, planetary.

It is important to recognise the plurality of flows that shape heath which can be stiffened or loosened by social and political forces. The field of movement for a person in a precarious housing situation is constrained by different socio-historical tensional forces than that of someone in a privileged affluent suburb. To think of health as a field is to acknowledge that atmospheric, geological, and socio-political circulations are the very fabric of the environment we co-habit.

What does this mean for physiotherapy, and its practice? This perspective challenges the scope of what we consider relevant and legitimate. If our “environment” extends to atmospheric, geological, social and cosmic circulations, then the field within which health and disease operate is vastly wider than our models typically acknowledge. Much of environmentalism, Nail observes, “has suffered from a myopic metaphysics of substance” (Nail, 2021, p. 44). The same could be said of much of healthcare.

Circulations

Nail identifies four patterns of circulation through which fields organise themselves. These patterns were already created by the cosmos and are iterated at every scale, from dark matter to living bodies (Nail, 2021, p. 51).

Centripetal fields circulate from the periphery toward a centre, gathering and concentrating. In the human body, we might recognise centripetal dynamics in the pooling of inflammatory mediators at a site of injury, or the centralisation of neural drive during a motor task. The historical biomedical flows themselves act centripetally, drawing symptoms inward toward a diagnostic centre. But Nail’s framework reminds us that no centre is ever fixed. Every centripetal gathering is a temporary capture, not an arrival at first or final cause, or indeed, truth.

Centrifugal fields circulate from a centre outward. Stars explode centrifugally, scattering newly forged elements across the cosmos. In clinical practice, centrifugal patterns appear in the systemic dispersal of hormones, or the way a single therapeutic encounter might ripple outward into various movement patterns and socioecological participation.

Tensional fields hold folds “both together and apart” simultaneously through strong links (Nail, 2021, p. 53). Orbital motion is tensional: the earth neither falls into the sun nor escapes it. Muscles, tendons, and ligaments hold bones together and apart, generating movement through differential distribution of forces. But tensional dynamics extend beyond biomechanics. Notions of therapeutic relationships themselves operate through tensional fields, holding partners (patients, clinicians, environments) in tension between proximity and distance, intervention and restraint.

Elastic fields allow folds to oscillate, expand, and contract without dissolution. Dark matter stretches spacetime elastically. In the body, elastic dynamics appear in the viscoelastic behaviour of connective tissue, the elastic recoil of lungs and arteries, the stretch-shortening cycle of muscle. What we might call “resilience” may be better understood as the elasticity of a field, the capacity to absorb perturbation and return, not to an identical state, but to a functional configuration of motion.

These patterns nest, knot, and overlap. Nail describes the earth as “a region of entangled and knotted celestial fields whose eccentric and pedetic contingencies participate in the major historical features of our planet” (Nail, 2021, p. 46). Pedesis, as discussed in the previous post, refers to the indeterminate but relational motion that underpins all material processes. The point here is that a field is not orderly in the way a machine is orderly. It is turbulent, iterative, and open.

Health as a Field

If we take this framework seriously, health cannot be viewed as a static state to be achieved or a norm to be restored. It is a field condition: the dynamic, metastable distribution of flows and folds circulating through centripetal, centrifugal, tensional, and elastic patterns simultaneously.

A body in health is a field where these circulations are sustained, where flows continue to move through folds, where the metastable cycles that constitute tissues, organs, and systems persist through continuous renewal. Disease, from this perspective, is less the presence of a pathological entity than a disruption in the field’s capacity to circulate. When centripetal gathering becomes excessive, we see fibrosis, contracture, accumulation. When centrifugal dispersal overwhelms the field, widespread dissipation manifests toward a loss of local coherence. When tensional balance is perturbed beyond a limit, the field tends toward structural instability, or toward the compensatory rigidity that nervous systems generate in response. When elasticity fails, the capacity of an entity to recover diminishes.

This is a processual account of health and disease, one that does not require us to locate pathology as a discrete object or attribute it to a single cause. It invites us instead to attend to patterns of circulation: where flows are altered, where folds have stiffened or dissipated and where fields have lost their capacity for self-iteration.

It is worth noting that the biologist Conrad Waddington proposed something adjacent to this thinking with his concept of homeorhesis, the tendency of processes to return not to a fixed state (homeostasis) but to a characteristic trajectory of change. Nail’s concept of delimitation, the continuous marking and transcending of limits, resonates here. Both suggest that regulation is not about holding still but about remaining in motion within dynamic constraints. This is a thread I intend to develop more fully in future work, perhaps through the lens of Lorenz attractors, where stability emerges from bounded turbulence and not from fixed thresholds.

The Clinician in the Field

One further consequence of thinking through the field is that the clinician is not external to it. If the field is the emergent pattern of circulating folds, then the physiotherapist is a fold within the same field. Our movements, our touch, our language, and our presence contribute to the circulation of the therapeutic field as much as the patient’s tissues do.

The biopsychosocial framework, for all its breadth, still tends to position the clinician as an external observer operating upon a patient who is the locus of bio, psycho, and social factors. This kinetic perspective dissolves this separation. The clinical encounter is itself a field event, shaped by gravitational, atmospheric, social, and historical circulations that extend far beyond the walls of a clinic.

Flow, Fold, Field

Across these three posts, I have tried to offer the beginnings of a processual vocabulary for physiotherapy, drawing on Thomas Nail’s philosophy of movement. In the first, objects emerged as metastable patterns of flowing matter. In the second, the fold revealed how motion produces persistence without permanence. And in this third, the field showed how folds distribute themselves into wider patterns of circulation that organise the movements we participate in.

Together, flow, fold, and field offer different ways of thinking that begins to describe how we are never analysing isolated bodies but are part of movement itself, at every scale. Health seen in this way is a dynamic field whereby there are fluctuations and disruptions occurring through patterns of circulation. One could quite imagine how this approach re-imagine physiotherapy. Therapy is already in motion with the cosmos and physiotherapists could work alongside these patterns of movement in the broadest possible sense.

Nail writes: “Only by profoundly shifting our frame and depth of inquiry will we be prepared to confront the most significant problems of our time” (Nail, 2021, p. 55). I believe physiotherapy stands at such a threshold. What it would mean to step across it, to build a truly kinetic physiotherapy, to embrace a philosophy of movement extending beyond our static and myopic history.

References

Nail T (2021) Theory of the Earth. Stanford: Stanford University Press.

Nail T (2023) Matter and Motion: A Brief History of Kinetic Materialism. Edinburgh: Edinburgh University Press.

Nail T (2024) The Philosophy of Movement: An Introduction. Minneapolis: University of Minnesota Press.