There is a subtle shift in perspective that occurs when we begin to think seriously about evolvability.
At first, evolution appears to be a process acting upon a relatively fixed system.
There is variation.
There is inheritance.
There is selection.
The system changes.
But if the developmental organisation of organisms affects which kinds of variation can arise, then the evolutionary process is not operating on a fixed set of possibilities.
And if evolutionary history can alter developmental organisation, then something more remarkable follows:
Evolution can change the conditions under which future evolution occurs.
This is a much stronger claim than saying that organisms evolve.
It suggests that evolution can alter not only the inhabitants of the evolutionary world, but aspects of the machinery that generates its future variation.
That is where the concept of evolvability becomes so important.
What is evolvability?
The word sounds deceptively simple.
An organism is evolvable if it can evolve.
But every lineage that persists through generations is, in some sense, capable of evolutionary change.
So the interesting question is not whether change is possible at all.
It is:
What kinds of heritable variation can a biological system generate, and with what consequences?
This immediately takes us beyond mutation alone.
Mutations can occur.
But a mutation is not automatically an evolutionary novelty.
For it to matter, several things must happen.
It must occur in a relevant hereditary context.
It must have some phenotypic consequence, or affect some process that eventually has one.
The resulting phenotype must be viable enough to persist.
The difference must be heritable.
And the environment must make the difference consequential in some way.
The path from genetic variation to evolutionary change is therefore structured.
Evolvability concerns something about that structure.
Not all variation is equal
Imagine two developmental systems.
In the first, small genetic changes tend to produce catastrophic developmental failures or negligible phenotypic effects.
In the second, genetic changes frequently produce coordinated, viable variations in organismal form.
Both systems can mutate.
But they are not equally evolvable.
This distinction is important because it reveals something that a simple mutation-centred picture tends to obscure.
The question is not merely:
How much variation occurs?
It is also:
What is the structure of the variation that occurs?
A developmental system can make some kinds of variation more accessible than others.
Some regions of phenotypic space may be densely connected.
Others may be separated by large developmental barriers.
Some changes may be highly correlated.
Others may be effectively unavailable.
Evolution therefore encounters a landscape that is already structured.
And that structure is not external to evolution.
It is part of the biological organisation through which evolution proceeds.
Evolution does not choose its variations
This returns us to the problem of agency.
If evolution can produce remarkably well-adapted forms, it is tempting to say that evolution "searches" for solutions.
But there is no search algorithm in the ordinary sense.
Evolution does not generate every imaginable organism and then inspect them.
It does not survey a complete possibility space.
It does not know which direction leads to greater fitness.
Variation arises through biological processes.
Development transforms variation into phenotypic outcomes.
The environment makes some outcomes consequential.
Selection changes their representation over generations.
The resulting lineage then provides the starting point for further variation.
There is therefore no need for an evolutionary agent.
What looks like exploration can emerge from the interaction of inheritance, development, organism and environment.
This matters because it gives us a more naturalistic interpretation of evolutionary possibility.
The topology of variation
Perhaps the most useful metaphor here is not a search space but a landscape.
Imagine that possible phenotypes form a terrain.
Some forms are close to one another.
Others are separated.
Some genetic changes move an organism only slightly across this terrain.
Others produce large jumps.
But now add development.
The terrain is no longer simply a neutral mathematical space.
Development determines which directions are easily accessible.
Some pathways are broad.
Some narrow.
Some branch.
Some terminate.
Some lead to viable forms.
Others lead to developmental dead ends.
And the topology of this terrain can itself change.
A new developmental mechanism may open a route that did not previously exist.
A structural innovation may connect previously separated regions.
A constraint may disappear.
Another may arise.
The landscape through which evolution moves is therefore not necessarily fixed.
Evolution can modify the terrain on which subsequent evolution operates.
The important word is "subsequent"
We should be careful here.
When we say that evolution changes the conditions of future evolution, we are not saying that evolution reaches forward in time and prepares itself for what is coming.
There is no foresight.
There is no evolutionary anticipation.
A developmental innovation does not arise because it knows that it will later be useful for generating variation.
Instead:
- a variation occurs;
- it becomes established under particular conditions;
- it alters the organisation of the organism;
- that altered organisation changes what further variations can produce;
- those variations are then subject to evolutionary processes.
The transformation of possibility is therefore historical rather than teleological.
The future is changed because the present has changed.
That distinction is essential.
A new possibility can be an old structure
Evolutionary novelty also does not necessarily require an entirely new structure.
We have already encountered exaptation.
A structure that evolved under one set of conditions can become consequential in another.
Once that happens, the structure may provide a basis for further evolution.
The important point is that an existing actuality can become the condition for a new possibility.
This is a recurring pattern:
actuality → new relation → new possibility
The wing, the feather, the limb, the jaw, the regulatory network—whatever the example—does not need to have been produced for its later role.
The later possibility emerges because the inherited structure enters a new configuration of relations.
This is one reason relational ontology helps here.
A structure's evolutionary significance cannot always be located entirely inside the structure itself.
Its significance depends partly upon what it can participate in.
The relation is evolutionary
Suppose a structure acquires a new function.
It is tempting to say:
"The structure evolved a new function."
But that formulation can make the function seem like a property that was somehow waiting inside the structure.
Sometimes a better question is:
What new relation has made this structure consequential in a new way?
The distinction matters.
A structure can remain materially similar while its evolutionary significance changes because its environment changes.
Or the environment can remain similar while the structure changes.
Or both can change.
The new evolutionary possibility arises from the relation.
This gives us a broader picture of adaptation.
Adaptation is not merely the optimisation of isolated traits.
It can involve the emergence of new relations between existing structures and changing circumstances.
The environment is part of the evolutionary machinery
This also means that we cannot treat the environment as a passive backdrop.
The environment affects which phenotypes matter.
But organisms affect environments too.
A population changes its environment simply by existing within it.
Organisms consume resources.
They produce waste.
They alter habitats.
They modify interactions with predators, competitors and symbionts.
These changes can affect the selective conditions experienced by subsequent generations.
So the relation looks something like:
organism → environment → selection → organism
And because organisms are themselves products of previous evolutionary histories:
past organism → present environment → future organism
The process becomes recursive.
The organism inherits an environment partly shaped by organisms that came before it.
It then changes that environment.
Its descendants encounter the altered conditions.
The future therefore inherits not only genes but, in various ways, altered relational circumstances.
The possibility of the niche
The concept of the niche becomes especially interesting here.
A niche is not simply a location.
It concerns a pattern of relations between organisms and their environments.
An organism's capacities determine which resources it can use, which conditions it can tolerate, and which interactions it can enter.
But those relations can also alter the environment.
This means that an evolutionary innovation can change not merely what an organism is but what ecological relations are available to it.
And once those relations change, new evolutionary possibilities can appear.
Again:
actuality changes relation; relation changes possibility.
We should resist turning this into a universal formula.
But it is becoming a recurring structural pattern across different evolutionary phenomena.
The organism changes the question
There is another reason evolvability matters.
Once we recognise that organisms can modify their environments and that developmental organisation shapes variation, the organism itself can no longer be treated as merely the passive outcome of selection.
It becomes a participant in the process.
This does not mean that organisms "direct" evolution in a conscious sense.
Nor does it imply that evolutionary change occurs because organisms need particular adaptations.
It means that the organism's organisation and behaviour form part of the causal conditions under which selection operates.
This is a much more modest claim.
And precisely because it is modest, it is useful.
The organism is neither:
the designer of its own evolution
nor:
a passive vehicle constructed by genes.
It is a participant within an evolving relational system.
The developmental system remembers
We can now return to the idea of inheritance as memory.
A developmental system contains the accumulated consequences of evolutionary history.
Not as a representation.
Not as a conscious record.
But as organisation.
A lineage that has evolved a particular developmental architecture carries that architecture forward.
That architecture determines how subsequent genetic differences can become phenotypic differences.
In this sense, development is a kind of historical memory.
The lineage does not merely remember particular traits.
It remembers, in its organisation, ways of producing traits.
This is a deeper form of inheritance.
The evolutionary past can be present not only in what organisms possess but in how they can change.
And that may be one of the most important ideas in the entire series.
Inheriting a way of becoming
We can now sharpen the previous essay's argument.
The organism does not inherit only a state.
It inherits a capacity for development.
That capacity is constrained.
It is structured.
It has pathways.
It has sensitivities.
It has possibilities.
And those possibilities are themselves products of evolutionary history.
A lineage therefore inherits not only:
what it is capable of being now
but also something about:
what it is capable of becoming next.
That does not mean that the future is encoded in advance.
Quite the opposite.
It means that the future is partially structured by the organisation inherited from the past.
This is where potential becomes particularly useful.
Potential is not a prediction.
It is a capacity.
And evolutionary history can change capacities.
Evolvability as transformed potential
We can therefore propose a tentative interpretation of evolvability.
Evolvability is not simply the amount of genetic variation a system possesses.
It concerns the organisation of its capacity to generate heritable variation.
That is already a relational concept.
The capacity belongs neither simply to the gene nor simply to the organism.
It arises from the organisation of the system through which genetic differences can become phenotypic differences and subsequently participate in reproduction.
So perhaps:
evolution can transform not only actual forms, but the potential for generating future forms.
That is a much more precise version of our governing thesis.
And it is importantly different from saying that evolution "creates possibility" in some mysterious metaphysical sense.
It changes biological organisation.
That altered organisation changes what kinds of variation can arise.
Those variations change what can subsequently be selected.
The transformation of possibility is therefore grounded in ordinary biological processes.
But is this really evolution?
We should now confront a possible objection.
Perhaps we have simply renamed evolvability.
If evolvability describes the capacity of lineages to generate heritable variation, why introduce the language of transformed possibility at all?
This is a serious challenge.
A philosophical concept is not useful merely because it can paraphrase a scientific one.
We need to ask what the broader language contributes.
One possibility is that it allows us to connect phenomena that are usually discussed separately:
- developmental constraint;
- exaptation;
- niche construction;
- evolvability;
- historical contingency;
- ecological feedback;
- innovation.
All of these concern, in different ways, the changing relation between what is actual and what can subsequently occur.
The phrase "transformation of possibility" may therefore function as a cross-level conceptual vocabulary.
It does not replace the biological concepts.
It asks whether they share a deeper structure.
That is a more modest—and more interesting—ambition.
The scientific concepts remain indispensable
This distinction is important.
We should not say:
"Evolution is really the transformation of possibility."
That would be premature.
Evolutionary biology has precise concepts for particular processes.
Mutation is not the same as development.
Development is not the same as selection.
Selection is not the same as niche construction.
Evolvability is not the same as historical contingency.
Our conceptual vocabulary should not erase those distinctions.
Instead, it can ask whether a relation among them becomes visible when we examine them together.
The philosophical framework is therefore interpretive, not a substitute for biological theory.
It helps us ask questions.
It does not get to dictate the answers.
Where possibility comes from
We can now make an important distinction between two very different ideas.
The first is:
Evolution discovers possibilities that already exist.
The second is:
Evolution changes the conditions under which possibilities become available.
The second is much closer to what we have been uncovering.
A new developmental architecture does not merely reveal an organism that was already waiting somewhere.
It changes the relation between genetic variation and phenotypic form.
A new ecological relation does not merely reveal a previously existing niche.
It changes what the organism can do and what consequences its traits have.
A new structure does not simply occupy a location in possibility space.
It can create new pathways through which subsequent structures can arise.
The historical process therefore has a constitutive role.
Not constitutive in the sense that organisms invent reality.
Constitutive in the modest sense that historical actualities alter the conditions of subsequent possibility.
Possibility is not probability
There is another distinction worth making.
A possibility is not simply a high probability.
Something can be possible but extremely unlikely.
Something can be highly probable without being inevitable.
Evolution operates with probabilities, but the concept of possibility is not reducible to probability.
This matters because our thesis concerns the structure of what can occur, not merely the frequency with which particular outcomes occur.
Development can make some phenotypic transformations accessible and others inaccessible.
Selection can alter their frequencies.
These are different questions.
Probability tells us something about how often an event occurs.
Possibility tells us something about whether and under what conditions it can occur.
Evolution involves both.
Actuality changes possibility
We can now return to the sequence that has been quietly organising the series:
potential → possibility → actuality
But the process does not stop there.
Once something becomes actual, it can alter the potential and possibility of the system.
So:
potential → possibility → actuality → transformed potential → transformed possibility...
This is the temporal structure we have been seeking.
It is not a mystical process of "becoming".
It is a way of describing how historical biological organisation accumulates.
A new actuality becomes part of the system.
The system is therefore no longer the system it was before.
Its capacities have changed.
Its constraints may have changed.
Its relations have changed.
Its future has changed—not because the future has been determined, but because the conditions from which the future will arise have been transformed.
That is a much more defensible formulation of the transformation of possibility.
The furrow deepens
We can return, cautiously, to our furrow.
A plough passes across a field.
It leaves a furrow.
The furrow changes the conditions under which water, seeds and subsequent movements interact.
A later pass of the plough does not encounter the original field.
It encounters a field already changed by the earlier pass.
The previous actuality has altered the conditions of the next possibility.
That is the structural point.
Evolution leaves furrows.
Some are genetic.
Some developmental.
Some ecological.
Some behavioural.
Some architectural.
They do not determine what will happen next.
But they change the terrain.
And because the terrain has changed, the future possibilities are not exactly the same as they were before.
The furrow is not the destination.
It is a changed condition of becoming.
The plough does not know the field
The metaphor also helps preserve the non-agentive character of evolution.
The plough does not know what crop will grow.
It does not aim at the next furrow.
Each movement is determined by immediate causes and constraints.
Yet the cumulative history of the field matters.
Likewise, evolutionary change does not require foresight.
There is no evolutionary consciousness surveying the future.
There is only the accumulation of actual changes and their consequences for subsequent processes.
This gives us a naturalistic alternative to both design and pure randomness.
Evolution is not designed.
But neither is it simply a sequence of unrelated accidents.
It is a historically structured process in which earlier changes alter the conditions under which later changes occur.
What evolution is beginning to look like
We can now place the pieces together.
The gene is not an agent.
It is a participant in an inheritance system.
Inheritance carries organisation from the past into the future.
Development transforms inherited organisation into organismal form.
Development constrains and enables variation.
Organisms participate in environments.
Organisms can alter those environments.
Environmental relations affect selection.
Selection alters the representation of hereditary variants.
And the resulting evolutionary changes can alter developmental organisation and therefore the structure of future variation.
The process is recursive.
Not circular in the sense of explaining everything by everything else.
Recursive in the sense that:
the outputs of one historical stage become conditions of the next.
That is what makes evolution historical.
And it is also what makes the transformation of possibility a potentially illuminating description of it.
But there is a final temptation
There is one temptation we must resist before we leave evolvability.
Once we see that evolution can alter the conditions of future evolution, it is easy to slide back into teleology.
We might begin to say:
Evolution evolves its own capacity to evolve.
Or:
Life becomes increasingly evolvable.
Or:
Evolution discovers new ways of evolving.
These formulations can be suggestive.
But they can also quietly reintroduce the agent we spent so long removing.
Evolution does not decide to become evolvable.
There is no general law requiring lineages to increase their evolvability.
Some lineages may become more constrained.
Some may lose capacities.
Some may become specialised.
Some may become evolutionary dead ends.
The transformation of possibility is not necessarily expansion.
It can be contraction.
Reorganisation.
Redirection.
Loss.
The future can become richer in some respects and poorer in others.
That asymmetry matters.
Possibility can disappear
This is perhaps as important as the emergence of new possibilities.
Evolutionary history can close doors.
Extinction removes lineages.
Developmental pathways can become inaccessible.
Structures can be lost.
Ecological conditions can change.
Genetic architectures can constrain subsequent evolution.
The history of life is therefore not a simple story of increasing possibility.
It is a history of changing possibility.
Some doors open.
Some close.
Some are transformed into doors leading somewhere else.
Some disappear entirely.
This is why our thesis must remain carefully neutral.
The transformation of possibility is not necessarily progress.
It is not necessarily increasing complexity.
It is not necessarily increasing freedom.
It is simply the claim that evolutionary history can alter the conditions under which future biological forms can arise.
The deepest implication
We can now return to the question with which we began this series:
Can the transformation of possibility actually illuminate biological evolution, or is it merely a beautiful extrapolation of our conceptual preferences?
Evolvability gives us our first serious reason to think that it may be more than the latter.
Evolution can affect developmental organisation.
Developmental organisation affects the kinds of heritable variation that can become phenotypically accessible.
Therefore evolutionary history can affect the structure of future evolutionary variation.
That is not merely poetic.
It is a biological claim with an identifiable mechanism.
The philosophical vocabulary adds something further.
It lets us see this as a relation among:
potential, possibility and actuality
across time.
An inherited actuality provides potential.
Development structures that potential into possibilities.
Some possibilities become actual.
Those actualities alter the system.
The altered system possesses a different potential.
And so the process continues.
The evolution of the conditions of evolution
Perhaps, then, the most disciplined version of our claim is this:
Evolution does not merely change what organisms are. Through historical changes in developmental, ecological and organisational relations, it can change the conditions under which further evolutionary change becomes possible.
That is a modest claim.
But it is not a trivial one.
It shifts our attention from evolution as a process that moves through a fixed world of possibilities toward evolution as a process whose history can reshape the terrain on which subsequent evolution occurs.
And that brings us to an even larger question.
If evolution changes its own conditions, then perhaps we should stop thinking of organisms as isolated products of an evolutionary process.
Perhaps the more appropriate object of study is the ecology of processes through which biological possibilities become available.
Genes.
Development.
Organisms.
Environments.
Lineages.
Each participates.
None needs to be the master.
And the possibilities of the whole emerge from their relations.
That is where our next step takes us.
We have been speaking of the biological system as though its participants were already assembled.
But they are not.
They themselves occupy ecological relations.
They depend upon one another.
They compete.
They cooperate.
They constrain one another.
They create opportunities for one another.
The terrain is not merely developmental.
It is ecological.
And once we enter that terrain, the question changes again:
What happens when the evolving organism does not merely inhabit an ecology of possibilities, but helps constitute it?
That is where the story of evolution begins to become considerably stranger. 🍷🙂
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