1. The Problem: A Conceptually Unstable Debate

Debates over plant cognition have long oscillated between inflation and dismissal. Some researchers attribute to plants forms of intelligence, learning, and memory, citing their complex signalling networks, environmental responsiveness, and adaptive plasticity (Trewavas, 2003; Baluška & Mancuso, 2009; Gagliano et al., 2016). Others reject such claims outright, emphasising the absence of neurons, centralised nervous systems, and representational architectures (Alpi et al., 2007; Taiz et al., 2019).

At stake is not merely terminology, but a deeper conceptual issue. If cognition is equated with neural processing or conscious awareness, plant cognition appears implausible by definition. If it is extended to any adaptive responsiveness, it risks collapsing into a trivial description of biological regulation.

These competing positions did not emerge arbitrarily. The identification of cognition with neural processing reflects the historical development of cognitive science, psychology, and neuroscience, where cognition was initially studied through organisms possessing nervous systems and complex behavioural repertoires. By contrast, broader definitions arose from attempts to account for adaptive behaviour wherever it occurs in living systems, including organisms lacking brains or nervous systems. Both approaches therefore capture important biological realities. The difficulty arises when either is treated as a universal criterion for cognition.

The debate thus reveals a missing middle:

A biologically grounded account of cognition that is neither neural nor trivial.

What is needed is a framework capable of recognising genuine organisational differences among living systems without reducing cognition either to specialised anatomical structures or to responsiveness in general.

The roots of this disagreement extend much further back than contemporary plant cognition research. Darwin’s The Power of Movement in Plants argued that root tips exhibit forms of sensitivity and coordination analogous to those performed by brains in animals. Since then, debates have repeatedly oscillated between two poles: attempts to reduce plant behaviour to physiological responsiveness and attempts to extend cognitive concepts such as sensation, intelligence, memory, and decision-making to plants. Contemporary controversies therefore revisit questions that have remained unresolved for more than a century. The persistence of these disagreements suggests that the central problem is not merely empirical but conceptual: how should cognition be understood in organisms whose organisation differs fundamentally from that of animals? (Pecere, 2025).

2. The Case For Plant Cognition

Proponents emphasise a range of well-established empirical features:

  • distributed environmental sensing
  • systemic electrical and hormonal signalling
  • developmental plasticity
  • memory-like modulation (e.g. stress priming)

Recent syntheses highlight the integrated and adaptive nature of plant responsiveness (Segundo-Ortín & Calvo, 2025; Novoplansky, 2024). Some experimental findings suggest forms of habituation or associative learning (Gagliano et al., 2016), reinforcing claims that plants exhibit genuinely cognitive behaviour.

Recent theoretical work extends this discussion beyond plants to single-cell organisms. Knafo et al. (2026) developed Bayesian models of learning in single-cell life, arguing that some cellular behaviours can be interpreted as adaptive inference about hidden environmental conditions. Such work strengthens the empirical continuity between cellular behaviour, learning, and adaptive decision-making, suggesting that learning-like processes may occur at surprisingly simple biological scales. At the same time, these findings do not by themselves establish cognition. Rather, they sharpen the question of how learning, evaluation, and cognition should be distinguished within living systems.

The significance of these observations lies not merely in the fact that plants and other organisms respond to their environments. All living systems exhibit some degree of responsiveness. The challenge is that many biological responses appear selective, context-sensitive, historically modulated, and coordinated across multiple organisational processes. Such behaviour often exceeds simple stimulus-response descriptions and encourages the use of cognitive language. Whether that language is justified remains the central question of the debate.

3. The Case Against

Critics argue that such interpretations rely on conceptual overreach.

Their objections are consistent:

  • cognition requires nervous systems
  • cognition requires representation
  • cognition requires consciousness

These criteria emerge from influential traditions within psychology, neuroscience, and philosophy of mind, where cognition has often been understood as the processing of representations within specialised neural architectures. From this perspective, cognition is inseparable from mechanisms capable of integrating information, generating internal models, and supporting complex behavioural flexibility. Plants lack such architectures, and critics therefore regard cognitive descriptions as inappropriate.

On this view, plant behaviour—however complex—remains biochemical regulation rather than cognition. Philosophical critiques further warn that extending cognitive language risks undermining its explanatory value (Hansen, 2024; Parise, 2024). If all adaptive behaviour is described as cognitive, cognition ceases to identify any distinctive organisational phenomenon.

The force of these criticisms should not be underestimated. They highlight a genuine danger within the literature: the tendency to infer cognition directly from behavioural complexity without specifying the organisational conditions that make cognitive description scientifically meaningful.

4. Where the Debate Goes Wrong

Both positions rely on unstable assumptions.

  • Proponents risk expanding cognition without clear criteria.
  • Critics restrict cognition to a narrow class of systems.

The result is a conceptual impasse.

Cognition is being defined either too narrowly or too broadly.

At the heart of the disagreement is a difference in explanatory focus. Proponents typically begin with behavioural observations. They emphasise the complexity, flexibility, and adaptive character of plant responses and argue that such behaviour resembles phenomena commonly described as cognitive in animals. Critics begin elsewhere. Their concern is not behavioural complexity but the organisational architecture traditionally associated with cognition, including representation, neural integration, and conscious processing.

As a consequence, the two sides often talk past one another. One side asks whether plant behaviour appears sufficiently sophisticated to justify cognitive language. The other asks whether plants possess the kinds of structures historically associated with cognition. Because these questions are not identical, the debate repeatedly generates disagreement without resolving the underlying issue.

The APS framework approaches the problem from a different direction. Rather than beginning with behavioural similarity or anatomical structure, APS asks what organisational conditions make cognitive description appropriate. The central question is not whether plants possess minds, nor whether their behaviour resembles that of animals, but whether they exhibit forms of viability-oriented organisation in which environmental differences are evaluated and integrated relative to the continued persistence of the system.

From this perspective, cognition becomes neither a specialised neural phenomenon nor a synonym for adaptive responsiveness. It becomes an organisational phenomenon grounded in the way living systems maintain themselves under changing conditions. The following sections develop this framework and examine its implications for understanding plant cognition.

5. APS: Cognition as Viability-Oriented Modulation

The APS framework reframes the problem.

Rather than asking whether plants have minds, APS asks whether they exhibit structured, viability-grounded evaluative modulation.

This shift in emphasis is important. Traditional debates often begin by searching for features associated with human or animal cognition, such as representation, consciousness, or specialised neural architectures. APS instead begins from the biological conditions that all living systems must satisfy. Every organism exists under conditions in which continued persistence cannot be taken for granted. Living systems must continually regulate their interactions with their environments in ways that sustain viability through time.

Within APS:

  • life is viability-oriented, constraint-closed organisation
  • agency is the modulation of activity relative to persistence
  • cognition is the organisation of biological significance across time. Within APS, significance explains what matters to the organism, while cognition explains how what matters becomes organised across time into coherent patterns of regulation, development, adaptation, and behavioural coordination.

The progression from life to cognition is therefore not abrupt. Living systems must maintain viability. The activities through which viability is sustained constitute biological agency. Agency, in turn, requires that differences in the environment and within the organism itself have consequences for continued persistence. Some conditions support viability, while others threaten it. Agency therefore introduces a distinction between favourable and unfavourable trajectories.

This distinction constitutes a basic form of evaluation. Living systems do not merely respond to change; they respond in ways that reflect the consequences of that change for their continued existence. Evaluation is therefore not an additional layer imposed upon biological activity but an intrinsic feature of viability-oriented organisation.

Cognition emerges when such evaluative activity becomes organised, coordinated, and integrated across multiple processes and scales. From this perspective, cognition is neither synonymous with all biological regulation nor restricted to organisms possessing nervous systems. It is a particular mode of viability-oriented organisation in which evaluative modulation contributes to the coordination of activity across the system as a whole.

Cognition is therefore not tied to neurons or representation, but to the organisation of activity in which differences are evaluated relative to viability.

5A. Biological Evaluation and the Emergence of Significance

The APS account of cognition depends upon a further distinction that has often remained implicit within plant cognition debates.

Living systems do not merely respond to environmental differences. They evaluate those differences relative to their continued viability. Some conditions support persistence, while others threaten it. Biological activity therefore occurs within an evaluative context generated by the organisation of the living system itself.

APS refers to this process as Biological Evaluation.

Biological Evaluation is the process through which agency generates significance. Through evaluation, environmental and internal differences acquire biological relevance. A change in nutrient availability, water access, herbivore pressure, temperature, competition, or signalling conditions matters because it alters the viability conditions of the organism.

The outcome of evaluation is therefore not information alone but significance. Significance identifies what matters to the organism relative to continued viability.

This distinction is important because information and significance are not identical. Organisms encounter countless differences in their environments, but only some become biologically significant. Significance emerges through the evaluative organisation of agency rather than from information considered in isolation.

Plant cognition is therefore not grounded simply in responsiveness, signalling, or information processing. It is grounded in the generation and organisation of biological significance.

6. Diagnostic Criteria

APS identifies cognition through organisational criteria rather than analogy.

Recent models of Bayesian learning in single-cell organisms illustrate why adaptive learning alone is insufficient as a criterion for cognition. Learning may occur in systems that do not exhibit the broader forms of cross-scale integration required for cognition in the APS framework.

The APS criteria are not independent tests assembled from different theoretical traditions. Rather, they identify interconnected dimensions of a single organisational phenomenon. Viability grounding establishes the biological context within which activity becomes meaningful. Normativity emerges because some trajectories contribute more effectively to viability than others. Cross-scale integration becomes necessary because viability is rarely maintained by isolated processes acting independently. Together these dimensions characterise the organisational conditions under which cognition becomes biologically significant.

Three dimensions are central:

Viability grounding
Modulation contributes to the system’s persistence under perturbation.

A system exhibits viability grounding when its activity influences the conditions required for its continued existence. Responses are not merely causal reactions to environmental inputs but participate in the maintenance of organisational integrity. The significance of a response therefore depends upon its contribution to viability.

Normative grounding
Some trajectories are better or worse relative to continued viability.

Because viability can be enhanced, maintained, diminished, or threatened, biological activity exhibits an intrinsic normative dimension. Certain responses contribute more effectively to persistence than others. This distinction provides a biological basis for evaluating success and failure without invoking external standards or conscious judgement.

Cross-scale integration
Local processes are coordinated within whole-system organisation.

Viability depends upon the coordinated activity of multiple processes operating across organisational scales. Local sensing, signalling, development, physiology, and environmental interaction must be integrated into a coherent pattern of activity. Cognition becomes identifiable when evaluative modulation contributes to this broader organisational coordination.

Taken together, these criteria identify cognition as a form of organised evaluative activity grounded in the maintenance of viability.

7. Plants as Minimally Cognitive Systems

On these criteria, plants qualify as minimally cognitive systems.

This conclusion does not follow from a single behavioural observation. It emerges from the organisation of plant activity as a whole. Plants exhibit viability-grounded responses, normative asymmetries, and extensive cross-scale integration, each of which contributes to their continued persistence under changing conditions.

Plants display numerous examples of viability-grounded activity. Defensive responses to herbivory, physiological adjustments to drought, alterations in growth patterns, and shifts in resource allocation all contribute to maintaining viability under perturbation. These responses are not isolated reactions but components of an ongoing process through which plants regulate their relationship with their environments.

Plant activity also exhibits normative grounding. Some developmental and physiological trajectories contribute more effectively to continued viability than others. Successful responses maintain growth, reproduction, and persistence, while unsuccessful responses increase vulnerability to environmental stress. The distinction between beneficial and detrimental outcomes is therefore built into the organisation of plant life itself.

Equally important is the extensive cross-scale integration characteristic of plant organisation. Hormonal signalling networks, electrical signalling, developmental coordination, and physiological regulation operate across the organism as an integrated whole. Environmental information detected locally can influence activity throughout the plant, producing coordinated responses that cannot be adequately understood at the level of isolated mechanisms.

The significance of these observations lies not in any single process considered independently but in their integration. Viability grounding provides the biological context, normative grounding provides evaluative asymmetry, and cross-scale integration coordinates activity across the organism. Together these dimensions constitute a form of organised evaluative modulation.

Plants therefore instantiate:

Minimal cognition as the organisation of biological significance generated through viability-oriented evaluation and integrated across multiple organisational scales.

This formulation neither anthropomorphises plants nor reduces cognition to simple responsiveness. Instead, it identifies a biologically grounded form of cognition emerging from the organisation of living activity itself.

APS consequently differs from stronger versions of plant neurobiology. The framework neither requires nor predicts plant neurons, plant brains, or plant consciousness. The presence of cognition is not determined by neural architecture but by organisational criteria. The question is not whether plants possess animal-like cognitive structures but whether biological significance is generated and integrated within viability-oriented organisation. APS therefore treats cognition as an organisational phenomenon rather than a neural one.

8. What Plants Do Not Exhibit

APS sharply limits the scope of this claim.

Plants do not exhibit:

  • representational cognition
  • centralised integrative architectures
  • conscious awareness

These limitations are important because they clarify what kind of cognition APS attributes to plants and what kind it does not. The claim is not that plants possess mental states analogous to those of humans or other animals with complex nervous systems. Nor is it that all forms of cognition are organisationally equivalent.

Instead, APS treats cognition as a graded biological phenomenon. Different forms of cognition emerge from different forms of organisation. Minimal cognition and representational cognition should therefore not be understood as competing alternatives but as distinct positions within a broader spectrum of cognitive organisation.

Plants occupy an important location within this spectrum. They exhibit organised evaluative activity grounded in viability, yet they lack the specialised structures associated with representational and conscious forms of cognition. Recognising this distinction allows cognitive language to be extended beyond nervous systems without collapsing all biological activity into cognition.

This distinction prevents anthropomorphic projection while preserving the biological reality of minimal cognition.

9. Development and Teleology

Recent critiques argue that autonomy-based accounts fail to explain the directed character of biological development (Rama, 2026). Development appears to involve forms of goal-directedness that extend beyond immediate self-maintenance. Organisms do not simply persist; they grow, differentiate, regenerate, and reorganise themselves through time. Any adequate account of biological organisation must therefore explain not only present viability but also the temporally extended trajectories through which viability is sustained and transformed.

APS addresses this challenge by situating development within the broader framework of viability-oriented organisation.

Development is not a separate goal beyond viability, but the temporally extended reorganisation of viability-oriented, constraint-closed organisation across scale.

From this perspective, development and cognition are not independent organisational domains. Both participate in the ongoing maintenance and reorganisation of living systems. Development extends viability-oriented organisation through time, while cognition contributes to the evaluation and modulation of activity within those developmental trajectories.

This relationship is particularly evident in plants. Growth patterns, developmental plasticity, resource allocation, and regenerative responses all involve the coordination of activity across multiple timescales. Environmental conditions are not merely detected; they influence the developmental organisation of the plant itself. Development therefore provides a longer temporal horizon within which evaluative activity acquires biological significance.

The directed character of development does not require externally imposed goals or predetermined programmes. It emerges from the organisation of living systems whose activity is continually oriented toward the maintenance and reorganisation of viability. Development is thus best understood as a temporally extended dimension of organised persistence rather than as a process separate from it.

Seen in this way, plant cognition participates in broader developmental trajectories through which viability-oriented organisation is maintained, modified, and reproduced across time.

10. Implications

Plant cognition also illustrates a broader principle emphasised throughout APS: cognition does not arise independently. It depends upon a sequence of organisational conditions that make cognition possible.

  • Life establishes organised persistence.

  • Agency enacts viability-oriented activity.

  • Biological Evaluation generates significance.

  • Integration organises significance into functional unity.

  • Cognition emerges as the organisation of biological significance across time.

Plant cognition therefore depends upon a prior organisational architecture rather than appearing as an isolated biological property.

The APS interpretation has implications that extend beyond the plant cognition debate itself.

First, cognition becomes a graded biological phenomenon rather than an all-or-nothing property. If cognition is understood as organised evaluative modulation grounded in viability, then different forms of cognition may emerge within different organisational architectures. The question is no longer whether a system possesses cognition in an absolute sense, but how cognition is organised and what forms it takes.

Second, the boundary of cognition shifts from anatomy to organisation. Traditional approaches often treat cognition as dependent upon particular structures, especially nervous systems. APS instead directs attention toward the organisational conditions that make cognition possible. This shift does not diminish the importance of specialised neural architectures. Rather, it situates them within a broader biological landscape in which cognition emerges through different forms of viability-oriented organisation.

Third, plants become especially important test cases for biological theories of cognition. Because plants lack nervous systems yet exhibit extensive signalling, coordination, plasticity, and evaluative modulation, they challenge assumptions that cognition must be tied to neural structures. They therefore provide a valuable opportunity to distinguish genuinely cognitive phenomena from the particular anatomical forms through which cognition is expressed in animals.

Finally, an organisational interpretation helps clarify the evolutionary continuity of cognition. If cognition is rooted in viability-oriented organisation, then more complex forms of cognition can be understood as elaborations of organisational capacities already present in simpler living systems. The apparent divide between non-cognitive and cognitive life becomes less abrupt and more developmentally intelligible.

These implications do not settle every question concerning cognition. They do, however, provide a framework within which cognition can be investigated as a biological phenomenon without reducing it either to neural mechanisms or to generic responsiveness. The debate is thereby transformed from a question about mental states to a question about the organisation of living activity.

11. Conclusion

The plant cognition debate has remained unstable because cognition itself has often been poorly grounded. When cognition is tied exclusively to consciousness, representation, or neural processing, plants are excluded by definition. When cognition is equated with adaptive responsiveness alone, the concept risks losing explanatory specificity. Neither approach provides a satisfactory biological account of what cognition is or why it arises within living systems.

APS resolves this difficulty by grounding cognition in viability-oriented organisation. The central question is no longer whether plants possess minds, but whether they exhibit organised forms of evaluative modulation that contribute to their continued persistence. From this perspective, cognition becomes a biological phenomenon whose significance derives from its role within the organisation of living activity.

The argument developed throughout this article has followed a cumulative progression. Living systems must maintain viability under changing conditions. The activity through which viability is sustained constitutes biological agency. Agency introduces distinctions between favourable and unfavourable conditions relative to persistence, giving rise to evaluation and normativity. When such evaluative activity becomes organised and integrated across scales, cognition emerges as a distinctive mode of viability-oriented organisation.

Plants satisfy these conditions. Their responses are viability-grounded, normatively structured, and integrated across multiple organisational processes. At the same time, they lack the representational, centralised, and conscious forms of cognition characteristic of many animals. They therefore occupy an important position within a broader spectrum of cognitive organisation.

Plants do not think in an anthropomorphic sense. Nor are they merely reactive systems. They evaluate conditions relative to viability, generate biological significance, and integrate that significance across multiple organisational processes.

Plant cognition is therefore neither illusion nor metaphor. It is a minimal form of cognition grounded in biological evaluation and the organisation of significance within viability-oriented, constraint-closed living systems.

Viewed in this way, plants occupy an important position within the broader APS cognition architecture. They demonstrate that cognition begins neither with consciousness nor with representation, but with the biological organisation of what matters.