Abstract

This article contends that Charles Sanders Peirce's semiotic framework, widely adopted as the theoretical bedrock of biosemiotics, carries unexamined anthropocentric presuppositions that render it unsuitable for grounding a universal theory of meaning in living systems. The critique unfolds along three primary lines of argument. First, it argues that Peirce's foundational sign categories—icon, index, and symbol—are not neutral logical structures but are deeply rooted in embodied, human-like sensory and cognitive capacities, making them inapplicable to the vast majority of non-human life. Second, it exposes the "interpretant problem," demonstrating that the concept of the interpretant necessitates "quasi-minds" with purposive and interpretive abilities that cellular and molecular processes lack. Third, the article highlights the absence of a robust "null category" in Peircean semiotics, a criterion for distinguishing genuine semiosis from non-semiotic processes, leading to a pansemiotic view where the concept of meaning loses its explanatory power. Through a critical engagement with leading biosemiotic theorists, including Jesper Hoffmeyer, Kalevi Kull, Marcello Barbieri, Frederik Stjernfelt, and Terrence Deacon, this analysis affirms the value of biosemiotic research while arguing for a necessary theoretical refoundation. It concludes by signaling a more promising alternative direction for understanding biological meaning, one centered on coordination-based and enactivist accounts rather than a sign-based framework inherited from Peirce.

Keywords: Peircean semiotics; biosemiotics; interpretant; semiotic threshold; embodiment; iconicity; indexicality

1. Introduction

1.1 The Biosemiotic Ambition

At the heart of the biosemiotic enterprise lies a bold and unifying claim, most famously articulated by Thomas A. Sebeok: "semiosis is the criterial attribute of life" [1]. This assertion anchors the ambition of biosemiotics to formulate a unified theory of meaning that spans the entire spectrum of life, from the intricate molecular interactions within a single bacterium to the complex symbolic systems of human culture. The promise of the field is profound: to dissolve the artificial barrier between the natural and the meaningful, demonstrating that sign processes are not an exceptional feature of the human mind but are, in fact, coextensive with life itself. To realize this ambition, the field overwhelmingly turned to the philosophical architecture of Charles Sanders Peirce. As the editor of the Essential Readings in Biosemiotics, Donald Favareau, notes, "Biosemiotics is largely Peircean semiotics applied to biological phenomena" [2]. The stakes of this foundational choice are immense. If Peirce's framework, upon closer inspection, proves incapable of bearing the weight of this theoretical edifice, then the entire field of biosemiotics requires either the discovery of new foundations or a significant and thorough reconceptualization of its core tenets.

1.2 The Argument in Brief

This article argues that Peirce's semiotic framework is not the neutral, universal grammar of sign processes that biosemioticians have taken it to be. Rather, it is a historically and culturally specific schema that implicitly presupposes forms of embodiment, perception, and cognition that the vast majority of living beings lack. The central thesis is that the uncritical application of Peircean categories to biological phenomena constitutes a form of anthropocentrism, projecting human-like modes of interpretation onto processes that operate according to fundamentally different principles. This critique is developed through three main claims:

  • The Embodied Presuppositions of Sign Categories: Peirce's core sign typology of icon, index, and symbol is not a set of abstract logical relations but is grounded in phenomenological experiences tied to a specific sensory and cognitive apparatus. Iconicity, based on resemblance, presupposes a perceiver capable of comparison and recognition, while indexicality, based on causal connection, presupposes an agent capable of tracking discrete objects and events in a structured environment. These capacities are not universal features of life.
  • The Interpretant Problem: The concept of the interpretant, the third element in Peirce's triadic sign relation, requires the existence of "quasi-minds" capable of purpose, learning, and varied determination. When applied to cells, molecules, or plants, the term is either stretched into a metaphor for any causal effect, thereby losing its explanatory power, or it smuggles in cognitive properties that these biological systems do not possess.
  • The Absence of a Null Category: A robust theory of meaning must be able to distinguish what is a sign from what is not. Peircean semiotics lacks a clear and principled way to make this distinction, creating a "pansemiotic" tendency where any causal process can be framed as semiosis. A framework that explains everything, in effect, explains nothing.

It is crucial to clarify that this article does not critique the empirical observations made by biosemiotic researchers. The fascinating discoveries regarding plant communication, bacterial quorum sensing, and cellular intelligence are not in dispute. The critique is aimed squarely at the theoretical framing of these observations within a Peircean model that is ill-suited for the task.

1.3 Structure of the Article

The argument will proceed as follows. Section 2 will outline the core tenets of Peirce's semiotics and explain why his framework, rather than Saussure's, became the foundation for biosemiotics. Sections 3 and 4 will mount a detailed critique of the application of iconicity and indexicality to non-human life, arguing that both categories are laden with anthropocentric assumptions. Section 5 will focus on the insurmountable difficulties posed by the concept of the interpretant. Section 6 will address the problem of the missing null category, arguing that the inability to define non-semiosis is a critical failure of the framework. Section 7 will explore the internal tensions and schisms within the biosemiotic field itself, showing how many leading figures are already moving away from a strictly Peircean model. Finally, the conclusion will summarize the argument and gesture toward a post-Peircean future for the study of meaning in life, one grounded in theories of coordination, enaction, and embodiment.

1.4 Why This Matters Now

This critique arrives at a pivotal moment for the field of biosemiotics. The theoretical consensus around Peirce is showing significant signs of fracture. Marcello Barbieri's development of "code biology" represents a direct challenge to the Peircean paradigm by proposing a model of organic codes without interpretants [3]. Terrence Deacon's work on autogenesis and emergent dynamics, while still using semiotic language, shifts the explanatory focus from Peircean triads to systems-level properties of self-organization [4]. Furthermore, scholars like C.J. Rodríguez Higuera have explicitly called for a "post-Peircean biosemiotics," recognizing the limitations of the foundational model [5]. The flagship journal of the field, Biosemiotics, has itself opened the door to this conversation, explicitly welcoming work that moves "beyond the Peircean paradigmatic model." The field is at a theoretical crossroads. By clarifying what must be abandoned in the Peircean inheritance, this article aims to help clear the ground for a more robust and scientifically grounded understanding of the life of signs and the signs of life.

2. The Peircean Foundation of Biosemiotics

2.1 Why Peirce and not Saussure

The theoretical allegiance of biosemiotics to Charles Sanders Peirce over his contemporary, Ferdinand de Saussure, was a deliberate and foundational choice. Saussure's semiology, developed from his lectures in linguistics, proposed a dyadic model of the sign, composed of a 'signifier' (the sound-image or written word) and a 'signified' (the concept). The relationship between these two elements was, in Saussure's famous formulation, fundamentally arbitrary [6]. The word "tree" has no intrinsic connection to the concept of a tree; it is a matter of social convention. This framework, while revolutionary for linguistics and cultural studies, was patently unsuitable for grounding a theory of meaning in the non-human biological world. Life, from the molecular to the organismic level, does not operate on arbitrary social conventions. A cell's response to a chemical gradient is not a matter of arbitrary agreement.

Peirce's framework, in contrast, appeared to offer a way out of this anthropocentric trap. His triadic model of the sign—a Sign (or Representamen), an Object, and an Interpretant—was not limited to the arbitrary relationship of the symbol. By including the categories of icon (signification through resemblance) and index (signification through physical connection), Peirce provided a conceptual toolkit that seemed capable of describing meaningful processes in the natural world, independent of language or convention. It was this apparent universality that made his work so attractive to biologists seeking to understand the semiotic nature of life. Peirce himself defined a sign in the broadest possible terms as "something which stands to somebody for something in some respect or capacity" [7]. For the pioneers of biosemiotics, this definition was capacious enough to include not just human language but also the scent of a predator, the shape of a protein, and the dance of a honeybee.

2.2 The Triadic Sign Structure

The cornerstone of Peircean semiotics is its irreducibly triadic sign structure. Unlike the dyadic Saussurean model, a sign process for Peirce necessarily involves three components. As he formally defined it:

"A Sign, or Representamen, is a First which stands in such a genuine triadic relation to a Second, called its Object, as to be capable of determining a Third, called its Interpretant, to assume the same triadic relation to its Object in which it stands itself to the same Object." [8]

This structure can be broken down as follows: the Sign (or Representamen) is the sign-vehicle itself; the form that the sign takes (e.g., a footprint, a word, a chemical molecule). The Object is that to which the sign refers (e.g., the animal that made the footprint, the concept of a tree, the presence of a nutrient). The Interpretant is the effect or meaning of the sign in an interpreting system; crucially, the interpretant is itself another sign (e.g., the thought "a deer passed this way," the activation of a metabolic pathway).

This structure is inherently dynamic and recursive. The interpretant of one sign becomes the representamen for a subsequent sign, creating potentially endless chains of semiosis. Peirce further distinguished between the Immediate Interpretant (the potential meaning of the sign), the Dynamic Interpretant (the actual effect produced by the sign), and the Final Interpretant (the ultimate, stabilized meaning that would be reached if the process of interpretation were carried to its ideal conclusion) [9]. This complex, process-oriented view of meaning seemed perfectly suited to the dynamic, unfolding nature of living processes.

2.3 Icon, Index, Symbol: The Core Typology

Perhaps the most influential aspect of Peirce's thought for biosemiotics is his classification of signs based on the relationship between the sign and its object. This typology provided the crucial tools for moving beyond the arbitrary symbol.

Icon: A sign that refers to its object by virtue of a similarity or resemblance. Peirce states that an icon "refers to the Object that it denotes merely by virtue of characters of its own" [10]. He further subdivided icons into images (sharing simple qualities), diagrams (representing relational structures), and metaphors (representing a parallelism) [11]. Biosemioticians have often applied this concept to molecular recognition, where the shape of a protein is said to be "iconic" of its binding partner.

Index: A sign that refers to its object through a direct physical or causal connection. An index, in Peirce's words, "refers to the Object that it denotes by virtue of being really affected by that Object" [12]. Smoke is an index of fire, a symptom is an index of a disease, and a pointing finger is an index of a direction. This category has been widely used in biosemiotics to describe signaling pathways, where a hormone or pheromone is seen as an index of a particular physiological state or environmental condition.

Symbol: A sign that refers to its object by virtue of a law, rule, or convention. A symbol "refers to the Object that it denotes by virtue of a law, usually an association of general ideas, which operates to cause the Symbol to be interpreted as referring to that Object" [13]. Words are the most common example. In the biosemiotic consensus, symbols are generally reserved for human language and culture, representing the highest and most complex level of semiosis.

2.4 Peirce's Categories and Their Phenomenological Basis

Underpinning Peirce's entire semiotic architecture are his three universal categories of experience: Firstness, Secondness, and Thirdness. These are not merely abstract logical divisions but are grounded in his phenomenology—his analysis of the structure of appearance. Firstness is the category of pure quality, feeling, and potentiality, independent of anything else. Secondness is the category of reaction, resistance, and brute fact—the experience of one thing acting upon another. Thirdness is the category of mediation, law, and representation—the experience of one thing bringing two others into relation.

It is critical to note the experiential, phenomenological language Peirce uses throughout his descriptions. His categories are derived from an analysis of conscious, embodied experience—the feeling of effort, the perception of quality, the recognition of a rule. This phenomenological grounding, while providing a rich and intuitive basis for his semiotics, will be shown in the following sections to be the source of its fundamental limitations as a universal framework for all life.

2.5 How Biosemiotics Deploys Peirce

Armed with this Peircean toolkit, the pioneers of biosemiotics set out to map the semiotic landscape of the living world. Sebeok expanded his initial work in zoosemiotics to the all-encompassing project of biosemiotics [16]. Jesper Hoffmeyer developed concepts like "semiotic scaffolding" and "code-duality" to describe how organisms are built upon and structured by layers of sign processes, from the genetic to the ecological [17]. Kalevi Kull extended the inquiry to the plant kingdom with his work on "vegetative semiosis" and wrestled with the "semiotic threshold"—the point at which non-living matter gives way to life and meaning [18]. More recently, Frederik Stjernfelt has applied Peirce's complex later work on "dicisigns" and "natural propositions" to argue for the existence of propositional meaning in non-human animals [19]. The unifying thread running through these diverse and sophisticated research programs is the consensus claim: that the Peircean categories of icon, index, and symbol, and the triadic structure of sign, object, and interpretant, are not merely useful analogies but are the universal and fundamental components of all living systems.

3. The Embodied Presuppositions of Iconicity

3.1 What Iconicity Requires

The concept of the icon, a sign that signifies through resemblance, is perhaps the most intuitively appealing of Peirce's categories for application to the biological realm. It seems to offer a non-arbitrary, non-linguistic basis for meaning. However, a closer examination reveals that the process of iconic semiosis is far from simple. For a sign to be interpreted as iconic, a series of complex cognitive operations must occur. The interpreting system must be able to perceive the sign and the object as two distinct entities, perform a comparison of features along some shared dimension of similarity, and recognize the resulting correspondence as meaningful and relevant. These are not trivial operations. They presuppose a sophisticated perceptual and cognitive apparatus capable of abstraction, comparison, and evaluation—not a universal property of life.

3.2 The Visual Bias in Peirce's Account

Peirce's own account of iconicity is deeply rooted in a visual and spatial sensorium. His primary examples and subtypes of icons—images, diagrams, and metaphors—betray this bias. Images "partake of simple qualities," which in his examples are almost always visual qualities like color and form [11]. Diagrams function by representing "analogous relations" between their parts and the parts of their object, a process that requires the ability to perceive and map spatial and structural relationships [11]. Metaphors, the most abstract of the hypoicons, involve "representing a parallelism," a cognitive feat of recognizing a structural similarity between two different domains [11].

When Peirce states that an icon signifies by "characters of its own," the unasked question is: which characters? The answer, implicit in his framework, is those characters that are perceivable and salient to the interpreter. The very notion of "resemblance" is not an objective property of the world but is a judgment made by a particular kind of embodied, perceiving mind.

3.3 Testing Iconicity Against Non-Visual Life

The limitations of the iconicity concept become starkly apparent when tested against the vast domains of non-visual life. Consider a single-celled organism like an amoeba or a bacterium. These organisms navigate their world with exquisite sensitivity, but their world is not one of images and forms. They respond to chemical gradients, pressure differentials, temperature shifts, and electromagnetic fields. In none of these modalities does the concept of "resemblance" in the Peircean sense apply. A bacterium does not perceive that a nutrient molecule "resembles" a memory of a past nutrient molecule. It simply has a receptor that binds to it, triggering a downstream causal cascade. The relationship is one of physical complementarity, not perceived similarity.

The same applies to the plant kingdom. A plant root growing towards a source of water is not comparing the "form" of the water molecules to an internal template. It is responding to a moisture gradient. When a plant releases volatile organic compounds (VOCs) to warn its neighbors of an insect attack, the neighboring plants do not perceive that the VOCs "resemble" the attacking insect. Their tissues react chemically to the presence of the compounds. The entire notion of resemblance-perception is a category error when applied to these life forms.

3.4 Biosemiotic Applications of Iconicity: A Critical Examination

Despite these fundamental problems, biosemioticians have frequently invoked iconicity to explain molecular and cellular processes. Kalevi Kull, for instance, has argued that vegetative semiosis is "based solely on iconic sign relations because code-based matching... is analogous to visual recognition of icons" [18]. The critical word here is "analogous." The analogy is doing all the theoretical work. There is no actual resemblance-perception occurring in the plant; rather, the human observer is making an analogy between the lock-and-key mechanism of molecular binding and their own experience of visual recognition. Calling this process "iconic" is not a scientific discovery; it is the application of a metaphor.

Other theorists have implicitly acknowledged this difficulty. Alexei Sharov's concept of "proto-icons" is an attempt to bridge the gap, but the "proto-" prefix is a concession that these processes are not the same as genuine Peircean icons [20]. Similarly, Günther Witzany's detailed work on plant communication describes complex processes of chemical modulation and response, which he frames under the heading of "semantic rules," but the underlying mechanism remains one of biochemical reactivity, not resemblance-perception [21]. The label "iconic" is imposed from the outside by a human observer, rather than being discovered as an intrinsic property of the system itself.

3.5 The Anthropocentric Sensorium

The root of the problem lies in the anthropocentric sensorium that underpins Peirce's examples and, by extension, his categories. His paradigmatic icons—portraits, photographs, maps, and diagrams—are all artifacts created by and for humans. They presuppose a body with eyes, a brain capable of processing visual information, the ability to perform spatial scanning, recognize forms, and map analogical relationships. As the cognitive linguists George Lakoff and Mark Johnson have argued, our most basic concepts are not abstract and disembodied but derive from our "direct physical experience" of "moving a human body through the environment" [22].

Peirce's icon is a product of this specific mode of being-in-the-world. It is not a universal, logical category that exists independently of embodiment. It is a projection of a particular kind of perception—human-like perception—onto the entire living world. To claim that a protein binding to a substrate is an instance of iconicity is to implicitly endow the protein with the perceptual and cognitive capacities of a human observer.

3.6 Conclusion: Iconicity Is Not Foundational

For these reasons, iconicity cannot serve as the universal, foundational ground of biosemiosis that many theorists have sought. The category is inapplicable to the vast majority of life, including bacteria, archaea, protists, fungi, and most of the plant kingdom. The coordination achieved by these organisms is not based on resemblance-perception. By forcing these processes into the category of the icon, biosemiotics does not reveal a hidden layer of meaning; it obscures the actual mechanisms of biological coordination under a misleading and anthropocentric metaphor. The search for a universal ground for biosemiotics must look elsewhere.

4. The Hidden Assumptions of Indexicality

4.1 The Structure of Indexical Semiosis

If iconicity proves too anthropocentric, the category of the index appears to offer a more promising foundation for a universal biosemiotics. An index, according to Peirce, is a sign that "refers to the Object that it denotes by virtue of being really affected by that Object" [12]. The connection is not one of resemblance but of physical causation or contiguity. The classic examples are powerfully intuitive: smoke is an index of fire, a footprint is an index of the animal that passed, a fever is an index of an illness. The apparent advantage of the index is its grounding in the seemingly objective and universal laws of causality. This has led many biosemioticians to see indexicality as the primary mode of semiosis in the biological world, describing everything from hormonal signals to predator-prey interactions.

4.2 What the Triadic Structure Presupposes

However, even this seemingly straightforward category carries a set of hidden presuppositions that are revealed when we insist on the irreducibly triadic nature of the Peircean sign. For a causal relation to become an indexical sign relation, it is not enough for A to cause B. A discrete sign-vehicle must be distinguishable from the general background context; a discrete object must be identified as the cause to which the sign "points"; and an interpretant must be generated that treats the sign as being about its object. This is a crucial distinction. A simple causal chain is a dyadic relationship (A causes B). An indexical sign is a triadic relationship (A is a sign of B for C). This structure presupposes a world that has already been carved up into discrete entities and legible causal chains—and an interpreting system capable of parsing the world in this way.

4.3 Plant Chemical Signaling: A Test Case

The problems with this model become clear when we examine a classic biosemiotic example: plant communication via volatile organic compounds (VOCs). When a plant is attacked by herbivores, it releases VOCs into the air. Neighboring plants detect these VOCs and, in response, upregulate their own defensive chemicals. The standard biosemiotic description frames the VOCs as the sign, the herbivore attack as the object, and the defensive response as the interpretant. This neat triadic structure, however, is an imposition that distorts the biological reality. What is actually occurring is a continuous process of chemical coordination, not a discrete act of signaling. There is no discrete "sign"; there is a continuous chemical gradient diffusing through a shared medium. The neighboring plant is not "interpreting" a sign as being "about" a distant attack; its tissues are being directly and continuously modulated by the chemical environment in which it is immersed. What we actually have is not a series of discrete signs but a process of continuous environmental coupling and coordination.

4.4 Bacterial Quorum Sensing: Another Test Case

A similar issue arises in the analysis of bacterial quorum sensing, often cited as a "textbook example of the rudimentary semiotic process" [23]. In quorum sensing, bacteria release signaling molecules (autoinducers) into their environment. As the population density increases, the concentration of these molecules crosses a threshold, triggering a collective change in gene expression and behavior (e.g., biofilm formation). The biosemiotic claim is that the autoinducers are signs that encode the state of the environment, eliciting a physiological interpretant. Once again, the critique is that the term "interpretant" is being evacuated of its meaning—here it means nothing more than "causal response." The concept has been deflated to the point of being synonymous with any effect in a causal chain. If every causal response is an interpretant, and every stimulus is a sign, then every chemical reaction is an act of semiosis. A concept that applies to everything ceases to have any explanatory power.

4.5 The Discrete-Agent Presupposition

Peirce's own examples of indexicality—footprints, weathervanes, pointing fingers—are drawn from a world of discrete agents and objects. A footprint is meaningful to an agent who perceives the world as populated by other discrete agents and who can track their causal traces through space and time. This is a specific, agent-centered way of engaging with the world. But this is not how most of the biological world operates. The roots of a plant do not track discrete objects; they modulate their growth continuously in response to gradients of water and nutrients. A mycorrhizal network does not pass discrete "signs" between trees; it maintains a dynamic equilibrium of chemical exchange across a continuous web. The triadic structure of indexicality is a poor fit for these forms of life.

4.6 Indexicality in the Human Mesocosm

The examples Peirce chooses are not accidental; they are drawn from what the phenomenologist Edmund Husserl called the Lebenswelt, or lifeworld—the middle-scale world of human experience. They presuppose the kind of embodied, spatial, and temporal engagement that a human being has with their environment. As the semiotician Göran Sonesson has argued, we should be cautious about assuming that Peirce's categories are universal logical forms. It is more likely that they represent "one particular phenomenology" among many [24]. This is not to say the categories are wrong, but that their domain of applicability is the human mesocosm, not the entire cosmos of life.

4.7 Conclusion: Indexicality Is Not Universal

Like iconicity, indexicality comes with a set of hidden assumptions that limit its universal applicability. It presupposes a world of discrete agents, discrete signs, and legible causal trails. It presupposes an interpreting system that can parse the world in these terms. While this model works well for describing the activities of many animals, it breaks down when applied to the vast realms of life—bacteria, plants, fungi—that engage with their worlds through continuous modulation and environmental coupling rather than discrete signaling. By stretching the category of the index to cover these processes, biosemiotics risks rendering the concept so broad as to be meaningless, thereby obscuring the very real and fascinating ways in which these organisms coordinate their existence.

5. The Interpretant Problem

5.1 Peirce's Quasi-Minds Requirement

The most significant and arguably insurmountable obstacle to applying Peircean semiotics to the whole of biology is the third term of the triad: the interpretant. While biosemioticians have often focused on the seemingly objective relations of icon and index, they have largely sidestepped the profound cognitive demands embedded in the concept of the interpretant. Peirce himself, in a crucial but often overlooked passage, made these demands explicit. In a 1906 manuscript, he wrote:

"For the purposes of this inquiry a Sign may be defined as a Medium for the communication of a Form. It is not logically necessary that anything possessing consciousness... should be concerned. But it is necessary that there should be two, if not three, quasi-minds, meaning things capable of varied determination as to forms of the kind communicated." [25]

This passage is devastating for the project of a universal biosemiotics. While Peirce dismisses the necessity of full-blown consciousness, he immediately replaces it with the requirement for "quasi-minds." What are these entities? They are, in his own words, "things capable of varied determination." This implies a system that can respond to the same sign in different ways depending on context, memory, or internal state—a capacity for learning, adaptation, and plasticity that is a far cry from the determinate, one-to-one causal reactions that characterize most molecular and cellular processes.

5.2 The Three Interpretants and Their Requirements

The cognitive demands of the interpretant become even clearer when we examine Peirce's tripartite division of the concept. The Immediate Interpretant is "the Quality of the Impression that a sign is fit to produce" [9]—implying a teleological dimension, a fitness for a purpose. The Dynamic Interpretant is "whatever interpretation any mind actually makes of a sign" [9]—framed as an act of "interpretation" by a "mind." The Final Interpretant is the most demanding of all: "the way in which every mind would act" [9]—the ultimate, normative conclusion of an exhaustive process of inquiry. To speak of a ribosome's "final interpretant" of a messenger RNA sequence is to engage in a category error of the highest order. These concepts are not properties of molecules or cells; they are properties of minds engaged in the process of inquiry and meaning-making.

5.3 T.L. Short's Critique: Teleology Without Minds

The philosopher T.L. Short, in his authoritative study Peirce's Theory of Signs, provides a rigorous critique that reinforces this point. Short argues that Peirce's semiotics is fundamentally a theory of teleology (purpose) [26]. For a sign to be a sign, it must be interpreted for some purpose. But, as Short points out, bacteria and cells lack purposes in the relevant, forward-looking sense. Their behavior is governed by immediate causal pressures, not by future goals. Short identifies three "fatal flaws" in Peirce's early attempts to ground semiotics—idealism, arbitrariness, and circularity—which persist in any attempt to extend it to non-cognitive biology. These problems can only be solved by a robust theory of purpose, which is precisely what is missing at the cellular level.

5.4 How Biosemiotics Handles the Interpretant

Faced with this problem, biosemioticians have resorted to a strategy of metaphorical extension and conceptual deflation. In a foundational 1991 paper, Jesper Hoffmeyer and Claus Emmeche describe the process of development as follows: "It is the zygote which is the subject in the process: It initiates the deciphering of the DNA-message and becomes gradually changed... in response to the interpretation" [27]. The language here is telling. The zygote is a "subject," it "initiates," it "deciphers," and it acts in response to an "interpretation." These are all cognitive terms, applied metaphorically to a biochemical process. What does "interpretation" actually mean here, if not simply "causal reaction"?

More recently, Terrence Deacon has attempted to naturalize the interpretant by arguing that semiotic properties "emerge from a higher-order reciprocal relationship between self-organizing processes" [4]. While this is a sophisticated and valuable contribution to systems biology, it represents a significant departure from Peirce. The explanatory framework is no longer the triadic sign relation but the dynamics of autogenic systems. The locus of meaning has shifted from the sign-interpreter interaction to the emergent properties of a complex system—a move that implicitly concedes the inadequacy of the original Peircean model.

5.5 The Deflation Problem

The most common strategy for dealing with the interpretant problem is to simply deflate the concept until it means nothing more than "effect" or "response." If the binding of a neurotransmitter to a receptor is "interpretation," if the transcription of a gene is "interpretation," if any causal response to a stimulus is "interpretation," then the term has been evacuated of all its specific content. As the critic D. Gálik has noted, this approach reduces biosemiotics to "only a language metaphor for describing life in terms of semiotics" [28]. It provides a new vocabulary but no new explanatory power.

5.6 Barbieri's Explicit Rejection

The severity of the interpretant problem is best illustrated by the fact that it led one of the founding figures of the field, Marcello Barbieri, to abandon the Peircean framework altogether. Barbieri developed his alternative theory of "code biology" precisely to avoid the mentalistic and unscientific connotations of the interpretant. As one analysis puts it, "Barbieri rejects Peircean biosemiotics on the grounds that this discipline opens the door to nonscientific approaches to biology through its use of the concept of 'interpretation'" [29]. Barbieri's model of "organic codes" involves rules of correspondence between two worlds of molecules, but it explicitly rejects the need for a third, interpreting entity. The fact that the founding editor of the journal Biosemiotics felt it necessary to create a new framework to escape the interpretant is a powerful testament to the concept's fundamental incoherence when applied to the molecular level of life.

5.7 Conclusion: Interpretation Without Interpreters

The interpretant is the lynchpin of Peirce's semiotic, and it is the rock upon which the project of a universal biosemiotics founders. The concept presupposes cognitive or "quasi-cognitive" capacities—purpose, varied determination, a tendency toward truth—that molecular and cellular processes simply do not possess. The attempts by biosemioticians to grapple with this problem have led them to either stretch the concept into a meaningless metaphor or to abandon the Peircean framework for other explanatory models. This is not a minor technical issue that can be resolved with a small adjustment. It is a fundamental flaw that undermines the entire Peircean apparatus as a foundation for understanding meaning across all of life.

6. The Missing Null Category: When Is Something Not Semiosis?

6.1 The Geertz Test

In his classic work The Interpretation of Cultures, the anthropologist Clifford Geertz provides a simple but profound distinction between a twitch and a wink [30]. A twitch is an involuntary, physiological spasm. It is unintentional, meaningless, and not directed at anyone. A wink, by contrast, is a deliberate, meaningful, socially embedded action. It is a sign, a communication, an act of semiosis. Any theory of meaning, to be considered robust, must be able to pass the "Geertz test": it must have a principled way of distinguishing the twitch from the wink. It must possess what can be called a null category—a clear criterion for identifying processes that are not semiotic.

6.2 Peirce's Semiotics Lacks a Null Category

Peircean semiotics, in its pure form, fails this test. Peirce himself never specified what would not count as semiosis. His triadic structure is so general and abstract that it can be imposed, with a little creativity, onto almost any process. Any event can be framed as a sign relation: any stimulus can be labeled a "sign," its cause can be labeled the "object," and the resulting effect can be labeled the "interpretant." If one defines semiosis broadly enough, as the action of a sign, then the entire universe appears to be perfused with signs. But as the philosopher of science Karl Popper might argue, a theory that can explain everything, and which cannot be falsified, explains nothing. A concept that applies to everything has no discriminatory power and therefore no explanatory value.

6.3 Biosemiotics Inherits This Problem

Biosemiotics, by adopting the Peircean framework wholesale, inherits this fundamental problem. Sebeok attempted to draw a boundary by asserting that "only living things and their inanimate extensions undergo semiosis" [16]. But this only pushes the problem back a step. Where, within the realm of the living, does semiosis stop? Kalevi Kull, grappling with this issue, considers the case of viruses and prions. He concludes that "There can be multiplication and spreading without any final causality, without any semiosis" [18]. This is a crucial concession. Kull acknowledges that some biological processes may not be semiotic. But the framework provides no clear criterion for why. The concept of a "semiotic threshold zone" acknowledges this indeterminacy but does not resolve it. It is a name for the problem, not a solution to it.

6.4 The Hair Colour Test

Consider a simple biological feature: phenotypic variation in human hair colour. This variation is genetically determined, biochemically produced, and perceptually salient. Is it semiotic? According to a rigorous application of the Geertz test, the answer should be no. While hair colour can be co-opted into cultural sign systems, the variation itself is not inherently meaningful. There are no reliable inferences to be drawn, no stable meanings, and no coordinated responses that are universally tied to it. Can biosemiotics, using the Peircean toolkit, confidently say that "hair colour is not semiosis"? It cannot. The framework provides no clear, non-arbitrary criterion for excluding it. One could always construct a triadic relation if one were so inclined, however contrived.

6.5 Non-Semiotic Variation in Nature

This problem is ubiquitous in biology. Not all phenotypic variation is adaptive signaling. Much of the variation within and between species is the result of neutral genetic drift, random mutations, or is simply an epiphenomenal byproduct of other developmental processes. Organisms are constantly bombarded with stimuli from their environment, but they respond to only a tiny fraction of them. A theory of biological meaning must be able to account for what is not meaningful—for the vast sea of noise in which the signals of life are embedded. Biosemiotics, by following Peirce's all-encompassing framework, lacks the conceptual tools to do this. It cannot distinguish the signal from the noise because it has no theoretical category for noise.

6.6 The Pansemiotic Temptation

The lack of a null category creates a powerful slide towards pansemiotism—the view that everything is a sign. Many biosemioticians are rightly uncomfortable with this position. Barbieri himself acknowledges this as a primary handicap of the field, noting that biosemiotics is often "wrongly perceived as... a view that promotes physiosemiotics, pansemiotics, panpsychism" [3]. C.J. Rodríguez Higuera critiques "the unnecessary expansion of semiotic attributes in order to give them enough explanatory power to either provide semiotic theories of everything" [5]. The problem is that this expansion is not an abuse of the Peircean framework; it is a direct consequence of its core logic. When the definition of a sign is sufficiently general, and there is no criterion for non-signhood, the pansemiotic conclusion is difficult to avoid. The field needs a principled boundary, but Peirce provides none.

6.7 Conclusion: The Cost of Universal Semiosis

A theory without boundaries is not a scientific theory. By inheriting Peirce's lack of a null category, biosemiotics is unable to make the most fundamental distinction required of any theory of meaning: the distinction between what is meaningful and what is not. This is not a peripheral problem but a central one. A theory of biological meaning that cannot say what is not meaningful is not a theory of meaning at all; it is a theory of everything, which is to say, a theory of nothing.

7. Internal Tensions and Alternative Directions

The critique that Peircean semiotics is ill-suited for biology is not merely an external one. It is amplified by a series of internal tensions, schisms, and alternative frameworks that have emerged from within the broader biosemiotic and philosophy of biology communities. These developments demonstrate a growing dissatisfaction with the orthodox Peircean model and point toward a post-Peircean future for the field.

7.1 The Code Biology Schism

No event makes the limitations of the Peircean framework clearer than the departure of Marcello Barbieri, the founding editor of the journal Biosemiotics. Faced with the intractable problems of the interpretant and the slide towards pansemiotism, Barbieri proposed a radical alternative: code biology [3]. His central insight was that life is based on "organic codes"—such as the genetic code, signal transduction codes, and the histone code—which are defined as rules of correspondence between two independent worlds of molecules. Crucially, these codes do not require interpretation in the Peircean sense. They are physical, arbitrary mappings established by molecular adaptors (e.g., tRNA molecules). Barbieri's model replaces the triadic sign with a focus on the material mechanisms of coding, describing the cell as a "trinity of genotype, phenotype, and ribotype" [3].

The significance of this move cannot be overstated. The field's founder effectively abandoned its foundational framework, arguing that a more constrained, mechanistic, and scientifically testable model of codes was superior to the philosophical apparatus of Peirce. While code biology has itself faced critiques—for instance, that a one-to-one correspondence model cannot fully explain the dynamic nature of living organization [31]—its very existence represents a major schism and a clear admission that the Peircean model is inadequate for the molecular level of life.

7.2 Deacon's Autogenesis Model

Terrence Deacon, another towering figure in the field, has taken a different but equally significant path away from orthodox Peirceanism. In his work on autogenesis, Deacon seeks to naturalize semiotic concepts by grounding them in the emergent dynamics of self-organizing systems [4]. He proposes a "molecular 'thought experiment'" to show how semiotic properties can emerge from the "higher-order reciprocal relationships" between catalytic and container processes. In this model, meaning is not a property of a sign-object-interpretant triad but is an emergent feature of a system's capacity to maintain and reproduce itself.

While Deacon continues to use semiotic terminology, his explanatory framework has shifted decisively from Peirce to systems theory and emergent dynamics. This move, while providing a powerful account of the origins of life and meaning, implicitly concedes that the Peircean framework itself does not do the foundational work. It must be supplemented—or arguably, replaced—by a theory of how semiotic properties are generated by underlying physical and chemical processes.

7.3 The Umwelt-Peirce Tension

Biosemiotics has long claimed to synthesize the work of two major thinkers: Charles Sanders Peirce and the biologist Jakob von Uexküll, who developed the concept of the Umwelt (the species-specific, subjective world of an organism). However, this synthesis papers over deep and likely irreconcilable philosophical incompatibilities. Uexküll was a Kantian constructivist who believed that the organism actively constructs its phenomenal world; reality is what appears to the subject [32]. Peirce, by contrast, was a metaphysical realist who believed that signs, through the process of inquiry, tend toward a true representation of a mind-independent reality. Furthermore, Uexküll was famously anti-Darwinian, whereas Peirce was a thoroughgoing evolutionist.

This fundamental tension has been noted by scholars like T. E. Feiten, who distinguishes between a deflated "Type 1 Umwelt" (simply the set of things an organism responds to) and a full-blooded "Type 2 Umwelt" (the phenomenal world as experienced by the organism) [33]. The attempt to fuse the realist Peirce with the constructivist Uexküll creates an unstable and incoherent foundation.

7.4 Enactivist Alternatives

A powerful alternative to sign-based theories of meaning has emerged from the enactivist school of cognitive science. Rooted in the work of Francisco Varela and Evan Thompson, enactivism argues that meaning arises not from internal representations or sign processing but from the dynamic "sense-making" activity of an autonomous organism interacting with its environment [34]. For enactivists, cognition is not the manipulation of symbols but the embodied, relational process through which a living being generates meaning by maintaining its identity in a precarious world. This framework is grounded in the theory of autopoiesis (self-production), not in Peircean sign relations.

While some have sought to find common ground between enactivism and biosemiotics [35], the tension remains profound. More radical enactivists, such as Daniel Hutto and Erik Myin, reject representationalism entirely, arguing that most cognition occurs without content-bearing mental states [36]. This position strikes at the very heart of the Peircean project, which is fundamentally a theory of how signs represent their objects to their interpretants.

7.5 What Remains of Biosemiotic Research

To critique the Peircean foundation of biosemiotics is not to dismiss the rich body of empirical research it has inspired. The detailed investigations into plant volatile signaling, bacterial quorum sensing, animal communication, and intracellular coordination remain immensely valuable. The contribution of biosemiotics has been to focus scientific attention on the informational and relational complexity of life. However, these phenomena can be described and explained without recourse to the Peircean apparatus. A more parsimonious and scientifically grounded vocabulary is readily available. We can speak of coordination, modulation, responsiveness, feedback loops, and environmental coupling. None of these terms require the baggage of signs, objects, and interpretants.

7.6 Toward a Post-Peircean Framework

The convergence of these internal critiques and external alternatives points toward the necessity of a post-Peircean framework for understanding meaning in life. Such a framework would not be centered on signs but on coordination. It would recognize that living beings coordinate their activities with their environments and with each other through embodied, relational, and situated engagement. Most of this coordination is not semiotic in the Peircean sense; it is a direct, dynamic coupling. The task for future work is to develop a theory of biological meaning-making that takes embodiment, enaction, and ecological context as its starting point, rather than a nineteenth-century theory of signs derived from logic and phenomenology.

8. Conclusion: After Peirce

8.1 Summary of the Argument

Charles Sanders Peirce developed his semiotics as a comprehensive theory of logic and inquiry, a tool for analyzing the structure of human cognition and scientific reasoning. His categories were born from a deep phenomenological reflection on the nature of experience, appearance, and reality as perceived by a human mind. The central argument of this article is that this origin is also the source of its fundamental limitation. When biosemiotics adopted the Peircean framework as a universal foundation for all life, it did not discover a pre-existing layer of universal semiosis; rather, it projected a specifically human-like cognitive and perceptual structure onto biological processes that operate according to different principles. The critique has shown that Peirce's categories presuppose forms of embodiment and cognition that the vast majority of living beings lack. Iconicity requires a capacity for visual-analogical perception that is absent in most of the biosphere. Indexicality, when properly understood as a triadic relation, presupposes a world of discrete agents and legible causal trails that is foreign to the continuous, gradient-based existence of many organisms. Most critically, the interpretant requires "quasi-minds" with purposive, adaptive capacities that cannot be scientifically located in molecular processes without reducing the term to a meaningless metaphor for "causal effect."

8.2 What This Critique Does Not Claim

It is essential to be clear about what this critique is not claiming. It does not deny that life is a profoundly relational, complex, and coordinated phenomenon. It does not reject the fascinating empirical observations of biosemiotic research, which have rightly drawn attention to the informational dynamics of living systems. Nor does it claim that meaning is an exclusively human property, possible only through language. The argument is more specific and more focused: it is that Peirce's particular framework, with its specific triadic structure and its phenomenologically-grounded categories, is an unsuitable and ultimately anthropocentric foundation for a universal theory of biological meaning.

8.3 The Significance of the Internal Debates

The necessity of moving beyond Peirce is not just an external critique but is a conclusion that emerges from within the field itself. The major theoretical developments in the study of biological meaning over the past two decades—from Barbieri's code biology and Deacon's autogenesis to the challenges from enactivism—all represent, in their own ways, a departure from the Peircean framework. These internal debates show a growing recognition that the orthodox model is insufficient. This article has sought to make the reasons for this insufficiency explicit and systematic. The field is already, in practice, moving beyond Peirce. It is time for its theoretical self-understanding to catch up.

8.4 Directions for Future Work

Abandoning the Peircean foundation opens up more promising avenues for future research. The goal should be to develop a theory of biological coordination that does not depend on the problematic concept of the sign. This would involve deeper engagement with frameworks like enactivism, ecological psychology, and phenomenology, which take the embodied, situated nature of the organism as their starting point [34] [37]. Such a research program would pay close attention to the species-specific forms of embodiment and environmental engagement, rather than assuming a one-size-fits-all semiotic model. Above all, it would be a framework that has what Peircean biosemiotics lacks: a robust null category. It would possess the theoretical clarity to distinguish the twitch from the wink, the merely causal from the genuinely meaningful, and in so doing, allow us to develop a more nuanced and scientifically grounded understanding of life.

8.5 Final Statement

Life does not run on meaning; it runs on coordination. Most living beings, for most of their existence, are not interpreting their worlds; they are trying to persist in them through a continuous, dynamic coupling with their environment. A theory that insists on seeing meaning everywhere ultimately sees nothing clearly. A theory that can distinguish coordination from interpretation, reaction from recognition—that theory might finally let us see life as it is, in all its diverse and wondrous forms, without the distorting lens of our own human-like way of being.

Ecks, Stefan. "The Embodied Limits of Peircean Semiotics: Why Peirce Cannot Ground What Biosemiotics Tries to Explain." Living Value Theory, livingvaluetheory.org.