Ability gives a system its aperture: the structured horizon of what the colony can, in principle, enact. But ability is never enacted neutrally. Every actualisation is nudged, tilted, biased by local conditions. This is the role of inclination.
In embryogenesis, inclination names the local tilts in readiness: metabolic gradients, mechanical stresses, positional asymmetries. Colonial organisms reveal this principle even more starkly: they dramatise how inclinations are not instructions, not functions, but relational biases that alter how an ability-field can be enacted.
In Volvox, inclination is written into difference—difference of position, difference of exposure, difference of history, difference of material constraint. These are not little local decision-makers. They are tilts in the readiness landscape.
Inclination is where potential begins to lean.
Inclination is relational asymmetry, not encoded role
Most developmental accounts smuggle in function through the back door:
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“anterior cells sense light,”
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“posterior cells handle reproduction,”
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“somatic cells specialise in motility.”
These are conflations of inclination with entrenched biological teleologies. What inclination marks instead is a shift in how local perspectives are disposed to enact the colony’s ability.
A somatic cell does not “choose” to beat its flagellum more vigorously. It simply finds itself in a region of the colony:
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with greater light exposure,
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with a particular mechanical orientation,
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with distinct metabolic flows,
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embedded in ECM of different elasticity,
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with neighbours whose own inclinations reinforce the local tilt.
Inclination is a relational condition, a bias in readiness—not a function encoded inside a cell.
Anterior–posterior polarity: a global tilt lived locally
Volvox colonies are anterior–posteriorly polarised. Anterior cells:
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are more sensitive to light,
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beat their flagella with a slightly different vector,
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often have distinct chloroplast organisation.
Posterior cells:
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house the gonidia,
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receive different shear forces from swimming,
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occupy a mechanically quieter region.
But polarity is not a label imposed from outside. It is the colony’s shape of inclination: a distributed gradient of local biases that collectively tune how the colony can turn, swim, or reorient.
Inclination explains why certain local actions produce global turning without invoking control centres or decision-making modules.
Inclination is not determinism: gradients can be rewritten
Inclinations are not fixed. They are exquisitely plastic.
Change the environment:
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shift the light angle,
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alter nutrient flow,
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vary shear stress,
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apply local chemical cues,
and inclination changes with it.
Anterior-like behaviour can appear in posterior regions under certain stimuli. Gonidia can be induced to express somatic-like behaviours when relational conditions shift. Cells reorient their beating axes when ECM stiffness changes.
These transformations only make sense once we stop treating inclination as “role” and treat it as local shaping of readiness.
Systems with flat inclination fields behave differently from those with steep ones. The colony’s behaviour has everything to do with how inclinations bias the enactment of its ability-field.
Local inclinations constrain global enactment
Consider phototaxis. The colony rotates as it swims; different regions are exposed to light cyclically. This cycling generates a dynamic inclination landscape:
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when a region faces the light, its cells tilt readiness toward stronger beat;
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when it rotates away, the inclination shifts;
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the whole colony enacts directional movement as an integration of these fluctuating biases.
In other words: behaviour is inclination modulating ability.
Inclination is also metabolic, mechanical, and historical
Because inclination is relational, it can be formed by multiple overlapping gradients:
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Mechanical gradients: ECM tension is not uniform across the colony; shear forces induce subtle local biases.
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Metabolic gradients: peripheral regions experience higher turnover; posterior regions may accumulate distinct metabolic histories.
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Developmental history: inversion imprints asymmetries; cells emerging on different trajectories maintain slight differences in their readiness-clines.
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Neighbourhood structure: a cell’s inclinations are partly shaped by the inclinations of neighbours—local alignments amplify and dampen readiness tilts.
Inclination is not a single gradient; it is a field of relational biases superimposed on the colony’s ability-architecture.
Inclination without functional roles: division of labour as perspectival gravity
The common story about Volvox is that it evolved a “division of labour”: somatic cells handle motility; gonidia handle reproduction. This is usually taken as a triumph of functional differentiation.
But the readiness framework reinterprets this entirely.
Division of labour is not the purpose of differentiation; it is the stabilised pattern of perspectival inclinations that emerges once the colony’s ability-field acquires certain structure.
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Gonidia are located where mechanical quiet allows reproductive inclination.
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Somatic cells are located where light exposure biases motile inclination.
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ECM geometry channels metabolic gradients that amplify this split.
This is perspectival gravity, not biological teleology.
Perturbing inclination reveals the architecture of readiness
If inclination is real and relational, then perturbations should reveal it.
Indeed, they do:
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Silence photoreceptors in a patch → that region stops tilting readiness toward light; the colony turns unpredictably.
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Mechanically compress one side → local beating axes shift; turning bias emerges on the compressed side.
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Alter ECM stiffness locally → beating synchrony changes, shifting global swimming trajectories.
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Induce somatic-like expression in gonidia → swimming destabilises as the inclination field becomes incoherent.
Inclination is not metaphor. It is materially measurable.
Inclination is where individuation begins to sharpen
Although individuation is the third wall of the readiness triad, inclination is where individuation becomes visible. Local inclinations create a perspectival asymmetry:
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These cells lean this way.
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Those cells lean that way.
Individuation—the sharpening of perspectival loci—is both shaped by and shapes these inclination gradients.
Inclination is the relational condition under which individuation can emerge as a distinction without becoming fragmentation.
The colony holds together not because it overrides individual perspectives but because local inclinations cluster into coherent, mutually reinforcing biases.
Where this leads
Ability gives a colony its horizon. Inclination leans that horizon toward particular enactments. Together they form the relational groundwork for the third pillar of readiness: individuation.
Individuation is where colonies such as Volvox reveal their deepest ontological stakes. For individuation here is neither the emergence of a higher-level organism nor the persistence of separate individuals. It is the perspectival recutting of shared potential.
In the next post, we will make this explicit:
Post 4 — Individuation: The Perspectival Life of Cells
How local construals of colonial potential constitute the colony itself; why individuality cannot be binary; and how perspectival alignment explains the emergence of coherent collective life.
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