The temporal and affective structure of living systems: A thermodynamic perspective

Abstract

Enactive approaches to cognitive science as well as contemporary accounts from neuroscience have argued that we need to reconceptualize the role of temporality and affectivity in minds. Far from being limited to special faculties, such as emotional mental states and timekeeping, these accounts argue that time and affect both constitute fundamental aspects of minds and cognition. If this is true, how should one conceptualize the relation between these two fundamental aspects? This paper offers a way to conceptualize and clarify the relation between temporality and affectivity when understood in this fundamental sense. In particular, the paper contributes to ongoing discussions of structural temporality and affectivity by combining enactive notions of self-maintenance with a thermodynamically informed view of the organization of living systems. In situating temporality and affectivity by way of their role for the maintenance of thermodynamic non-equilibrium, I will argue that temporality and affectivity should be regarded as two sides of the same coin—that is, two distinct ways of highlighting one and the same process. This process corresponds to the continued differentiation of organism and environment as functional poles of a living system. The temporal and affective structure of living systems may thus be seen as the warp and weft by which living systems maintain themselves in terms of thermodynamic non-equilibrium.

1. Introduction

Temporality and affectivity have often been seen as merely peripheral to the study of mind. More recently, however, dynamical and enactive approaches to cognitive science have argued that temporality (Kelso, 1995; Spivey, 2007; Kirchhoff & Kiverstein, 2019) and affectivity (Varela et al., 1991; Thompson, 2007; Colombetti, 2014; Di Paolo et al., 2017) are fundamental to understanding minds and cognition. The question put forward in this paper is as follows: insofar as temporality and affectivity are fundamental features of minds, what is the relation between these two fundamental features of mind? It will be argued that the best way to understand the relation between affectivity and temporality is that both highlight different aspects of one operationally irreducible process. Namely, the process of systemic maintenance through a thermodynamic differentiation.

The inherent temporal, or diachronic, nature of minds is deeply ingrained within approaches to cognitive science drawing upon the phenomenological tradition in philosophy (Gallagher & Zahavi, 2008, pp. 91-2; Gallagher, 2017a, pp. 7-12; Gallagher, 2020, p. 26). However, many recent enactive accounts contend that temporality, in turn, arises from a successive series of affective perturbations (Jonas, 2001; Varela & Depraz, 2005). Others still, take this interconnection between temporality and affectivity as an invitation to further explore and reconceptualize the relation between affectivity and temporality as structural features of mentality, seeking to give a proper place to affectivity and feeling at the roots of lived being (Froese, 2020; Fuchs, 2018, p. 111, 120). In this paper, I will take up the call to integrate affectivity and living temporality by arguing that both temporal and affective structures constitute a single affective-temporal dynamic through which living systems maintain themselves.

The paper consists of two main sections: the first outlining and discussing developments within the understanding of temporality and affectivity as structural features of minds and cognition and the relation between them; the second providing a novel account of this relation through the lens of the thermodynamic organization of living systems.

Section 1 starts by considering different conceptualizations of temporality and affectivity in terms of faculties such as time perception and basic emotions in contrast to more recent faculty-independent ones. This serves to distinguish temporal and affective structure from prior means of conceptualizing time and affect, and to motivate the pervasive, or fundamental, nature of temporality, and affectivity. The second part of section 1 then delves into the current literature on these more basic conceptualizations of temporality and affectivity and their interrelation, arguing that neither temporality nor affectivity can be taken as the ground from which the other emerges.

Section 2 offers an account of the emergence of temporality and affectivity as fundamental structures of living systems through their unified role in keeping organism and environment in an entropically asymmetrical polarized relation, explicating the mutual dependency and mutual implication of temporal and affective structure. Centrally, as fundamental features of minds, temporality and affectivity emerge from a unified process which determines the co-emergence of the living organism and its respective environment as means for the overall living system.

2. Structural temporality and affectivity

That time and affect are interrelated at the level of how we experience ourselves and our environment is thoroughly documented through research as well as by everyday examples. Most readers will probably recognize the experience of sitting in a dentist’s waiting-room and finding that time seems to slow to an agonizing crawl. In such situations, our subjective experience of temporal duration is modified in accordance with affective disposition. This interconnectedness of affectivity and experienced temporal duration is in no way limited to their manifestation in dentist’s waiting rooms.

Experimental and behavioral research demonstrates a pervasive correlation between temporality and affectivity. The experience of time and temporal intervals, conscious or unconscious, depends on a range of different factors including motivation, attention, and emotion (Droit-Volet & Meck, 2007; Soares et al., 2016). Conversely, the affective salience of objects in the world varies with their perceived temporal distance (Trope et al., 2007). A similar connection is evinced by studies of pathology. Conditions related to motivation and emotional well-being such as depression are accompanied by feelings of temporal displacement impinging on time interval estimation (Droit-Volet, 2013; Di Lernia et al., 2018); meanwhile, disorders correlated with impairments in emotion regulation, such as ADHD, also cause global and specific impairment in temporal capacities such as timing and time-management (Barkley et al., 1997; Noreika et al., 2013). Taken together, behavioral and pathological research indicates that temporal and affective capacities are closely interrelated.

The examples show a clear interrelation between temporality and affectivity at the level of conscious experience. However, this paper will be investigating the relation between time and affect at a different level: namely at the level of the structural organization of living being. In this first part, I will trace discussions of structural temporality and affectivity from contemporary neuroscience to phenomenological and enactive approaches to minds and cognition. My aim here is not primarily to argue that temporality and affectivity are fundamental features of mind, but simply to present some of the established reasoning behind the recent increase in research treating them as such, from neuroscience and cognitive science alike.

2.1 Structural temporality and affectivity in neuroscience

First, consider the neuroscientific distinction between affectivity and emotional episodes. The traditional view of how affect figures in our brains postulates the existence of modules for basic emotions. The theory of basic emotions encompasses a cluster of theories contending that emotions such as anger, fear, and happiness are natural kinds. It is thus held that the human brain contains evolutionarily endowed networks for emotions which have evolved to enable our ancestors to cope with their varying everyday tasks (Ekman et al., 1969; Piórkowska & Wrobel, 2017). However, this view conflicts with an accumulating body of experimental research. For one, research on self-reported emotions and facial patterns fails to demonstrate any clear-cut distinction between different basic emotion categories (Barrett, 2006a; Barrett, 2017, pp. 22, 69). ¹ In contrast, psychological constructionist models such as the theory of constructed emotion contend that emotional episodes and feelings are sociocultural categorizations of situational (core) valence and arousal (Russell, 1991; Barrett, 2006b; 2017). That is, the core affective structure of biological minds should not be confused with emotion-concepts. According to these neuroscientific accounts, at least, far from being restricted to specifically emotional experiential episodes, affectivity is a constant aspect of the cognitive structure underlying experience as such.

Much as with affective structure, temporal structure should not be confused with conscious awareness of time or with mental timekeeping. Whereas temporal structure is a ubiquitous feature of living beings, the notions of an independent temporal dimension as well as of special faculties for keeping track of it is a relatively recent invention (Landes, 1983; Nowotny, 1992). Indeed, some human cultures still either do not use time in this sense or have no concept of a unified time altogether (Sinha et al., 2011). This absence is also reflected by the neuroscience of time. Brains do not measure the passage of time but are themselves organized by its own internal dynamics (van Bree et al., 2022; Sterling & Laughlin, 2015). Much as there seems to be no specific neural module for emotions, neither do brains seem to contain special modules or localized networks specifically for keeping track of the time (Rubia, 2006; Buzsáki, 2019, pp. 261, 72-9). Instead, our basic cognitive makeup is itself partly constituted by temporal patterns (Varela et al., 1999). Timing and temporality are as such much more fundamentally ingrained within living tissue: temporal structures such as rhythmic and dynamically variable oscillational patterns are ubiquitous features of neuronal networks. ² As with basic emotion modules, the notion of a special module or faculty for observing time simply underestimates the pervasiveness of temporal structures for nervous systems and living beings in general. ³

This has decisive consequences for temporality and its interconnection with affective structure. First of all, it means that relation to an independent dimension of time is not a part of how living systems process time. This will be detailed in later sections taking up a thermodynamic perspective. In short, whereas a faculty-based approach to temporality depends on the observation of a posited independent dimension of time, over and above systemic dynamics, a thermodynamic approach posits no such thing. Or, more precisely, time becomes a product of system dynamics. This is because a thermodynamic perspective redefines time’s arrow from an irreducible dimension or background structure into a statistical product of changes in systemic entropy. In other words, the thermodynamic perspective taken up in later sections does not have to posit a linear dimension of time—as is observed or represented under a faculty-based view of temporality—because from a thermodynamic perspective time’s dimensional nature is a derivative of statistical tendencies within the system itself. ⁴

As seen thus far, temporality and affectivity in living beings require a shift from a faculty-based approach to a structural approach. Before proceeding to the thermodynamic perspective and its broader implications, the rest of this section will treat with some of the existing structural approaches to the relation between temporality and affectivity from enactive and phenomenologically informed cognitive science.

2.2 Structural temporality: from Husserlian time-consciousness to vital dynamics

Within enactive approaches to cognitive science, several accounts have emphasized the fundamental role of temporality and affectivity for minds and especially for consciousness. Regarding temporality, these may be traced back to Husserl’s investigations of inner time-consciousness (Husserl, 1991; Noë, 2004; Thompson, 2007; Gallagher, 2020). For Husserl, instead of representing time by mental acts such as memory and anticipation, subjectivity itself comprises a temporal flow which constitutes time and the temporal unity or “being-all-at-once” by which we normally define the “now” (Husserl, 1991, p. 382, 81). As such, approaches informed by phenomenological philosophy have argued that conscious experience emerges from a continuous and extended temporal field integrating past and future (Gallagher & Zahavi, 2008, p. 86; Fuchs, 2018, p. 56). The key takeaway is much in line with Buzsáki’s research a century later: in its most basic manifestation, temporality is not just a product or content of consciousness but is an essential feature consciousness as such. Using the terms outlined above, temporality is a structural feature of conscious experience.

Two key innovations stand out in contemporary adaptations of this structural view of how temporality relates to mind. First is an expansion in scope from consciousness to sensorimotor behavior. Whereas Husserl’s analyses concerned the temporal structure of conscious experience, current accounts invoke temporal structure to understand perceptual, and cognitive processing in general (Varela, 1999; Kelso, 1995; Grush, 2006). As such, the temporal structure would encompass multiple timescales ranging from conscious awareness to unconscious sensorimotor capacities (Varela, 1999; Gallagher, 2017a, p. 9, 145; Gallagher, 2020, p. 29). Much as Husserl argued that experience possesses an inherent “internal” temporal structure, recent accounts describe the inherently temporal dynamic and diachronic structure of cognition in general (Kirchhoff, 2015; Chemero, 2009; Spivey, 2007, p. 41). Despite the difference in level of description between the Husserlian and contemporary accounts of the temporal structure of minds, they share the exchange of a facultative view of temporality for a structural one. Rather than treating temporality as an input for cognition, temporality is a component of cognition itself. In other words, in its most basic form, temporality is not primarily something that the mind must work to keep track of—on the contrary, it is a constitutive feature of how minds work in the first place.

A second crucial innovation is the systematic integration of temporality with biological normativity. Because of its expansion in scope from consciousness to living agents in general, it has been argued that the temporal structure of minds and cognition must be understood in terms of the deep continuity of mind and life (Thompson, 2007; Di Paolo et al., 2017; Gallagher, 2017a; Kirchhoff & Froese, 2017; Kirchhoff & Kiverstein, 2019, p. 104). Minds are not only temporally extended processes: they are living processes. Beyond the unified serial structure characteristic of Husserlian time-consciousness, the normative character of life imposes a directional or “striving” character on the temporal structure of minds. ⁵ But if, as the enactive literature suggests, “intrinsic temporality has its roots in life” (Kiverstein, 2017) then the temporal structure of minds must be seen—not only in terms of extended or extensive dynamic processing, but also—in terms of the purposive striving characteristic of life (Gallagher, 2017b). Striving is here a way of characterizing living biological systems’ self-maintaining organization (Thompson, 2007; Di Paolo et al., 2017; Kauffman, 2019). In this regard, it has been suggested that the specific role of affect and affectivity needs to be readdressed by enactive approaches to cognitive science (Berkovich-Ohana, 2017; Froese, 2020). Insofar as living temporality is defined by striving, this would imply that the interrelation between temporality and affectivity runs much deeper than that of mental faculties such as emotions and time perception. I will here treat with an existing line of argument for how the striving character of living systems may explain the relation between temporality and affectivity.

This potential answer is provided by phenomenological and enactive traditions—and especially ones which follow the philosopher Hans Jonas in the pursuit of uncovering the continuity between minds and biological organization. Here, if the temporal structure of minds arises from out of the same metabolic processes by which living systems uphold their “vital imperative” for transformative self-production (Di Paolo, 2021), this same affective impetus may be able to illuminate life’s temporal structure. That is, minds may have the temporal structure of dynamic orientation precisely because minds themselves are rooted in the particular vital processes that uphold a living system.

2.3 Structural affectivity: the Jonasian turn

Within enactive approaches, the most influential account of the relation between structural temporality and affectivity is drawn from Hans Jonas’ “principle of mediacy” (Thompson, 2007; Di Paolo et al., 2017) The interconnection of life’s temporal structure and the vital striving inherent to living beings is a key topic of phenomenological thought. This includes precursors such as Bergson, Freud (Bernet, 2010; 2020), and Schelling (Vallier, 2013; McGrath, 2010; Michelini, 2020), as well as key debates between Heidegger and Scheler (Hackett, 2013). ⁶ More recently, this interconnection has been treated by authors engaging with the life sciences from a phenomenologically inspired perspective (Jonas, 2001; Canguilhem, 1991, pp. 125-131; Plessner, 2019). ⁷ In turn, these latter accounts—and especially that of Hans Jonas—have had a substantial influence on contemporary enactive approaches to cognitive science (Thompson, 2007; Di Paolo et al., 2017).

According to Jonas, affect (or as he names it, “desire”) manifests a (spatio)temporal distance to be closed in a triadic relation between affect (desire), perception, and motility (Jonas, 2001, p. 86). ⁸ Conversely, temporality may be understood as affect’s directional horizon. For Jonas, life’s unique operation lies precisely in the productive tensions generated by the interaction between disclosed spatiotemporal distance and the normative directedness of affect (desire) towards closing said distances. As formulated by Jonas,

[d]istance in both [spatial and temporal] respects is disclosed and bridged: perception presents the object “not here but over there”; desire presents the goal “not yet but to come”: motility guided by perception and driven by desire turns there into here and not yet into now. Without the tension of distance and the deferment necessitated by it there would be no occasion for desire or emotion generally. The great secret of animal life lies precisely in the gap which it is able to maintain between immediate concern and mediate satisfaction, i.e., in the loss of immediacy corresponding to the gain in scope. (Jonas, 2001, p. 102, p. 102)

In this sense, an organism’s world corresponds to the spatiotemporal ⁹ distances of affective impulses afforded by its potential for sensing and acting. ¹⁰ In the organisms’ experienced world desire plays the role of a striving impetus which opens a temporal horizon of distances to be closed by motility.

A crucial feature of Jonas’ conceptualization of the relation between structural temporality and affectivity—as well as of its contemporary adoption within enactive approaches to cognitive science—is the attribution of primacy of affectivity over temporality. For Jonas and recent adoptions alike, whereas both temporality and affectivity arise in conjunction with one another (Jonas, 2001, p. 101; Varela & Depraz, 2005, p. 73), structural affect (or emotion, as Jonas calls it) takes precedence over temporality. This is because, as they argue, temporality likely requires an originally altered affective state as its antecedent (Varela & Depraz, 2005, p. 62). In Jonas’ formulation,

[animal nature] is constituted by the triad of perception, motility, and emotion. Emotion, more basic than the two it binds together, is the animal translation of the fundamental drive which, even on the undifferentiated preanimal level, operates in the ceaseless carrying-on of the metabolism (Jonas, 2001, p. 126).

Similarly, for Varela and Depraz,

[t]he conclusion is that the emergence of the living present is rooted in and arises from a germ or source of motion-disposition, a primordial fluctuation. That this has to do with a primordial fluctuation motivates our notion here that affect precedes temporality: affect implicates as its very nature the tendency, a ‘pulsion’ and a motion that, as such, can only deploy itself in time and thus as time. (Varela & Depraz, 2005, p. 69, p. 69)

On both accounts, the germ in question is designated “under the term valence, that is, the primordial constitution of self-affection as a dynamic polarity, as manifesting in the form of a tension that takes several forms: like-dislike, attraction-rejection, pleasure-displeasure” (Varela & Depraz, 2005: 70). For Jonas, this minimal form of affective valence takes the form of irritability or appetition (Jonas, 2001, p. 99, 101). On both versions, the Jonasian account hence conceptualizes temporal structure as the implementational offshoot of an originative affective structure.

In sum, the Jonasian account presents one candidate for an understanding of the relation between temporality and affectivity as structural features of minds and cognition. According to this account, temporal structure is ultimately derived from affectivity. However, as will be seen in the following, this account faces serious pressure in terms of both its phenomenological roots and as an adequate understanding of the influence of temporality upon affective structure.

2.4 Problems with the primacy of affectivity

The issues with the Jonasian account of the relation between temporality and affectivity pertain, respectively, to the prioritization of affectivity and its implications for an account of mind in general. In the first case, the issue is that the subsumption of temporal structure as secondary to affective structure would effectively reverse a key insight of phenomenology: namely that temporal flow cannot be derived from a sequence of discrete mental—or affective—states.

To illustrate this point, consider the difference between a movie reel (a layout of discrete images) and a movie (a single moving image). A movie reel of individual images by itself is insufficient to produce a sensation of movement and flow. In order to produce the experience of movement, the images must be ordered into an already existing temporal flow. If not for this preexisting flow, the reel would simply comprise an inert spatial layout of individual pictures. Sequential succession thus already presupposes a temporal flow over which to exchange one state for another. This is simply to say that temporal flow is not something which can be derived from a series of individual instances. Accordingly, as in the Husserlian account, the continuity of experience does not unfold from a series of frozen moments, but requires an underlying continuous flow (Husserl, 1991, pp. 79, 92; Husserl, 1973, p. 73, 87). Similarly, Merleau-Ponty emphasizes that the temporal character of the mind is precisely not like a series of individual moments, like pearls on a string, but a single continuous flow, like a landscape viewed from a moving carriage (Merleau-Ponty, 2012, p. 443). The presence of a sequence of events itself—such as the sequence of affective perturbations—presupposes temporal structure in order for one state to lead into the next.

This point has most commonly been leveraged against a view of temporality as arising from a succession of representational states; but the same principle applies for conceptualizations of temporality in terms of a succession of affective states. Pace the Jonasian account, temporal structure cannot be derived from discontinuous time-slices—regardless of whether these take the form of representation or successive affective perturbations. Accordingly, one cannot subsume temporality as the product of discrete affective moments any more than as the product of discrete mental representations. Or, to put it more sharply, subsuming structural temporality as a product of discrete states is to do away with it entirely.

The second issue with the Jonasian account is that the assertion of the primacy of affectivity implies a functional separation between (affective) goal-orientation and (temporal) executive dynamics specifically rejected by an enactive or broadly embodied approach to cognition. On the Jonasian account, the interrelation of affectivity and temporality, as structural features of mind, may be likened to a recursive sequence of non-intellectualized identification and action execution. The claim that structural affectivity precedes temporality depends upon a functional separation between what Varela and Depraz call impulsion (-as-affect) and deployment (-as-time) (Varela & Depraz, 2005, p. 69, cited above). Affective structure here specifies what the living system strives for (its goal or end) whereas temporal structure specifies how it achieves its goal (its executive trajectory or course). This functional separation of goal-specification and execution corresponds to the theoretical bifurcation of cognition and behavior under traditional cognitivist and modular theories of mind—respectively, (cognitive) task specification and (behavioral) execution (Fodor, 1983). But this view of a functional distinction between goal-designation and execution (or impulsion and deployment on the Jonasian account) does not hold up. The notion of a pervasive functional division between direction and execution is widely criticized (Cisek & Kalaska, 2010; Hurley, 1998; Spivey, 2007, p. 238). ¹¹ I will here consider some of these as they might apply to the Jonasian account.

What the Jonasian account designates as directive affective impulsion is itself manifested and constrained in accordance with the temporal horizons that are made available by sensorimotor capacities. ¹² The emergence of affective goals is in this sense contingent upon temporal structures. On the one hand, this may seem amendable to the Jonasian view insofar as affective impulsions remain constrained by their deployment in terms of temporality or time. On the other hand, such interdependence seriously challenges the notion of a functional separation. Moreover, maintaining a primacy of (affective) impulsion over (temporal) deployment ignores the crucial and reciprocal role that ongoing deployment plays as a source of (affective) impulsions. Even granting the functional separation of affective impulsion and temporal deployment, affective goals emerge from ongoing temporal structures no less than vice versa. That is, as a distinct function, (temporal) deployment is not just the result of (affective) impulsions but is also a key source thereof. Ongoing temporal structures actively generate the goals that manifest to living systems in the first place. As argued by ecological psychologists, information about the environment is not only given in accordance with potential actions but is also actively generated through action (Wagman et al. 2020; Gibson 2015, p 187ff). Consider how visual depth-perception relies on continuous locomotor movement creating differential variation in optic flow between proximate and distal surroundings. Conversely, the fly-ball catcher’s locomotion steadies the optical trajectory of a ball, making it easier to trace and catch (Chapman, 1968; Robertson & Kirchhoff, 2019). In both cases, ongoing deployment plays a central role in generating and maintaining a goal. In this sense, temporal structure is not just a constraining and enabling influence but is a central part of the formation of impulsions.

In summation, asserting the primacy of structural affectivity over temporality risks falling back on key progress made in the study of minds and cognition. First, it arguably loses sight of structural temporality outright; second, it implicates an implausible functional separation between goal-orientation and action. This section has outlined the current status of research on the interrelation between structural conceptualizations of affectivity and temporality from neuroscience and enactive cognitive science. On the one hand, living temporality, as characterized by vital purposive striving, appears to have its roots in a primitive form of affectivity, such as the germ of valence considered by Jonas, Varela, and Depraz. At the same time, however, we cannot derive temporal flow from a series of discontinuous perturbations—affective or otherwise. Nor can we separate goal-orientation from behavior and action. Insofar as temporality and affectivity are fundamental aspects of minds, their apparent interconnection cannot be explained in terms of one being reducible to the other.

In order to get a better understanding of the relation between temporality and affectivity as genuinely structural features of living minds, the next section will offer a perspective which takes it cue from a thermodynamic interpretation of living systems. Through this thermodynamic lens, my goal is to provide a view of how temporality and affectivity emerge in relation to their functional role for biological systems.

3. The formation of temporal-affective dynamics in living systems

This section will provide an account of the relation between structural temporality and affectivity. A key element of this account will be an understanding of living systems based on their characterization from thermodynamics. Before developing this thermodynamically informed perspective, I will provide a brief introduction to certain aspects of how entropy may specify the organism and environment as complementary functional poles of the living system. The first part of the section will focus on this task, while the latter parts take up the main task of fleshing out the positive account of the role and relation between structural temporality and affectivity in living systems.

3.1 A living system is a differential relational system

Living beings are biological systems comprised of processes arranged around continuous exchanges of matter. This exchange is commonly regarded in terms of a transfer of energy from the environment to the organism. Although, strictly speaking, this transferal is not of energy but “low entropy” (Prigogine & Nicolis, 1985; Kauffman, 2019). Entropy denotes the amount of disorder in any given system. Because there are always more possibilities for disorder than order, entropy always increases (Schrödinger, 1967, p 70). To illustrate, if I put two green balls (G) and two red balls (R) into a box and pick them out at random, I am more likely to get a mixed sequence of balls than an ordered one. This is because each sequence is equally probable and disorderly sequences (GRGR, GRRG, RGGR, RGRG) outnumber ordered sequences (GGRR, RRGG). This statistical imbalance towards more disordered outcomes increases exponentially with more elements involved. For more complex systems, this makes the gradual increase of entropy virtually inevitable. This means that a system that starts at a high degree of orderliness, such as a box with all green balls on one side and all red on the other, will gradually move towards a more and more even distribution of colors on either side. As different states become gradually more evenly distributed the system will eventually reach thermodynamic equilibrium, at which point the system will cease changing. For example, the heat from a hot cup of coffee eventually dissipates into the surrounding air, at which point the temperature will cease changing. For the cup of coffee, thermodynamic equilibrium is reached when the inner states (the temperature of the coffee) have approximated the outer states (room-temperature). Any complex system will thus keep changing until it eventually reaches equilibrium.

This notion of equilibrium may be related to the temporal and affective structure of living systems insofar as both are understood in their role for keeping the living system viable. In this regard, two aspects of equilibrium in relation to living systems should be noted. First, reaching thermodynamic equilibrium means death for living systems because it means the depletion the system’s potential for change. Accordingly, living systems maintain themselves at far from equilibrium states. In order to avoid thermodynamic equilibrium and death, a living system must maintain low entropy in the organism (Nicholson & Dupré, 2018, p. 15; Walsh, 2016, p. 14). Second, non-equilibrium may be understood as a property of the relation between different parts of the system. To avoid equilibrium, a living system must not simply maintain a generally “low” entropy in the organism, but an entropic asymmetry between an internal (low) and external (high) entropy. In a living system, the internal states denote its organism whereas the external states denote its (phenotypically specified) environment. In this sense, the phenotypically specified environment is itself already part of the system—as opposed to an organism-independent physical or geometrical space.

In sum, living systems avoid death by maintaining a differential relation within its system constituting an organism and an environment. In this way, the living system is constituted at the interface of organism and environment. This interface is commonly referred to in terms of a boundary. However, it should be noted that construing this interface as a boundary is potentially misleading for a few reasons. First, the distinction between the organism and its environment is primarily functional rather than necessarily material. As evinced by membrane-less organelles, not all biological systems depend upon a material boundary for this functional distinction (Mitrea & Kriwacki, 2016). ¹³ Even where such a distinction does comprise a material tissue layer, such as a cell membrane, its functional role far exceeds that of a material barrier (Wu et al., 2014). Accordingly, a sensorimotor interface is functionally distinct from a mediating boundary (Aguilera et al., 2021). Secondly, organismic life (whether micro- or macrobiotic) is not predominantly comprised of neatly separated individuals but of relational systems spanning various entangled lifeforms and their environmental niches (Oyama, 2000; Dupré, 2012, pp. 85–100). As outlined above, the organism and environment both arise as functional poles of a relational system. The relational character of this interface is also emphasized by enactive accounts, despite their usage of boundary to determine this interface. For enactivism, the precarious and dynamic character of organismic self-maintenance means that organism and environment co-emerge in a process of mutual specification (Thompson, 2007, pp. 60, 65, 99; Werner, 2021). ¹⁴

On this view, inner and outer states do not designate independent realms but functionally interlocked “poles” within a single organism-environment system (Turvey, 2009; Rolla & Figueiredo, 2021). Insofar as living systems distinguish between inner and outer, this distinction is a product of its continuous metabolic processes: in this way, the functional “boundary” between organism and environment is a fragile and renegotiable achievement of the overall system itself (Kirchhoff & Kiverstein, 2019, p. 16; Sutton, 2010, p. 213). Rather than the concept of a boundary, with its connotation of a separating barrier, a more accurate description might be a gradual horizon merging higher and lesser degrees of functional polarity between in and out. The co-emergent inner and outer states (organism and environment) serve as functional poles for maintaining the entropic asymmetry keeping the system from thermodynamic equilibrium. In other words, both organism and its respective environment are defined for the system by how they serve in upholding this differential relation. This is where temporal and affective structure comes in.

Let us recap the main points of this thermodynamically based understanding of living systems thus far. First, living systems require the maintenance of entropic non-equilibrium in order to maintain their capacity for change. Insofar as non-equilibrium is a relational property, this makes the living system itself inherently relational. Second, the way that the living system upholds entropic non-equilibrium is by maintaining a difference in entropy within the system. This relational system is therefore centered around the interface between two component poles. These poles, defining the organism and the environment, respectively, are coequally constituted as parts serving the overall relational thermodynamic non-equilibrium system. Note that both organism and environment co-emerge for the living system as means to an end—that is, as means for the perpetuation of the broader relational system. This functional role of organism and environment as means to uphold a dynamic differential relation is decisive for understanding their structural temporality and affectivity.

3.2 The continuity of entropic profiles and affective structure

As functional poles by which living systems maintain their entropic non-equilibrium, organism and environment are shorthand for their respective designation for lower and higher entropy. ¹⁵ The remainder of this paper details what this implies for their respective affective and temporal structure, as well as the relation between these structures. I will argue, first, that there is a continuity between the affective phenomenal manifestation of the organism and environment and their respective functional role for the maintenance of entropic non-equilibrium; and, secondly, due to the nature of time from a thermodynamic perspective, the specification of the affective structure of, respectively, organism and environment is simultaneously a way of referring to their respective temporal structure.

First, let us consider the environment from a thermodynamically characterized living system. What has been said thus far about the environment should be indicatory of the need to distinguish between the environment as manifested to the living system and as a physical or geometrical space. Unlike an organism-independent physical or geometrical space, the environment of a living system manifests in terms opportunities of significance to systemic viability (Gibson, 2015; Turvey, 2018; Chemero 2003, 2009; Spivey, 2007). The living system’s environment “works for” the system insofar as it discloses a world defined in terms relevant to the survival of the system (Thomas et al., 2019). Another way of saying this is that the environment as given for the living system shows up through its functional tone: in short, its relevance for the perpetuation of the living organism-environment system (Fultot & Turvey, 2019). ¹⁶ In terms of the phenomenology of the living system, the phenotypically specified environment corresponds to Uexküll’s notion of the umwelt (von Uexküll, 2010; Baggs & Chemero, 2019). The phenotypic environment is the environment relative to the organism’s sensorimotor capacities—what the organism can perceive (effect-signs or merkmal) and what it can do or effect (effect-mark or wirkmal)—and its affective disposition or mood, characterized by the organism’s needs. Besides sensorimotor capacities, affective mood dictates the functional tone of the world we encounter. For example, the mood of a hermit crab, such as being hungry or being conch-less, will modify the functional tone of an encountered sea anemone as, respectively, “food” or “free real estate” (von Uexküll, 2010, p. 92; Laland et al., 2016). The environment encountered by the hermit-crab comprises a web of systemic significance—of potential interactions of affectively determined salience.

Taking the environment as an organism-relative field of afforded opportunities and dangers reveals a continuity between the thermodynamic description outlined thus far and the phenomenological perspective of the previous section. As one pole of the living system, the environment—in the rich form of a landscape of affordances for action (Gibson, 2015) or a symphony of functional tones (von Uexküll, 2010; Fultot & Turvey, 2019)—comprises a web of opportunities and dangers relevant to the system’s aim of maintaining itself as a differential entropic relation. This environment, rich in significance may be seen as basically affording opportunities for siphoning low entropy into the organism. The phenomenal constitution of environments for living systems in terms of affective structure thus remains continuous with the thermodynamic non-equilibrium system’s designation of a high entropy pole. As such, the functional significance of the environment presents a link between the affective aspect of the phenomenal reality of the living system and its description in terms of entropy.

The same continuity of applies to the organism once taken as a functional means for the relational system. Whereas the environment may be specified by opportunities for action and interaction, the organism may be specified as a repository for regulatory processes and sensorimotor capacities. In this sense of a means employed by a relational system, just as there is no environment over and above its significance as affordances, there is no organism over and above its enablement of action and regulation (Di Paolo et al., 2017). Complement to the environmental landscape of affordances, the organism comprises a web of sensorimotor capacities and activities in continuous and metastable development (Di Paolo, 2021; Bruineberg et al., 2021; Walsh, 2015). Organisms are constituted by the homeostatic and allostatic imperatives that they serve as means for (McEwen & Wingfield, 2010; Damasio, 2018, p. 35).

In this sense, the organism displays the same continuity with its respective thermodynamic profile within the living system as the environment. That is, the organism manifests at its most basic as subsets of the living system designated for lower entropy. As with the environment, this provides a way to ground our understanding of the organism as a part of the phenomenology of living systems within the distinguishing functional role of the organism for maintaining entropic non-equilibrium. As a repository for regulatory and sensorimotor enabling capacities, subsets designated as organism also correspond to a certain systemic privileging in terms of structural integrity. This is because being designated for lower entropy implies a specific affective structure of heightened prioritization for the living system (as will be unpacked presently). As will be seen shortly, this entropic and affective structure also corresponds, in turn, to a temporal structure.

It should be noted that since low entropy designates a higher degree of orderliness, or structural integrity over time, the inner pole (organism) thus enjoys a certain privilege which may give the impression of the organism constituting the living system itself (Moreno & Barandiaran, 2004; Weber & Varela, 2002; Kauffman, 2019, p. 8–12). This would, however, be a mistake from the fundamentally relational thermodynamic perspective taken here. Insofar as systemic non-equilibrium is a relational property (of entropic asymmetry between two poles) the organism is intrinsically one part of a relational system. To see why this is the case, consider the subtle difference between non-equilibrium and simply having an organism at low entropy. Were we to take the organism as the living system itself, such a system would remain at thermodynamic equilibrium with itself, no matter how low its entropy. Insofar as a living system is dependent on non-equilibrium, the organism specified for low entropy only serves the perpetuation of the system to the extent that this designation for low entropy facilitates a dynamic asymmetry in entropy within a broader system. The designation of the organism for low entropy only becomes a source of dynamic non-equilibrium in the context of the broader relational system. Effectively, simply having a system at low entropy would correspond not to a living system, but to its fossilized remains. ¹⁷

3.3 Temporal structure is defined by entropic profile

Finally, the connection between significance and the entropy-relative nature of living systems provides the essential link between affectivity and temporality. Thus far, the environment and organism of the living system have been described primarily in terms of their affective structure: their relevance to the saliences and interests of the system. However, when we consider the entropy-relative nature of living systems, the characterization of environment and organism in terms of affective structure is implicitly also a characterization of their respective temporal structures.

In the first section, it was briefly indicated that a thermodynamic perspective eliminates the need to posit an independent dimension of time as a background structure. As shown there, temporal structure is an intrinsic, structural feature of living system and their brains (Buzsáki, 2006; Varela et al., 1991; Rubia, 2006) rendering a faculty-based relation to an independently conceptualized temporal background redundant (Buzsáki, 2019). Finally, as will be outlined presently, thermodynamics provides an explanation for why postulating an independent background structure is redundant.

From a thermodynamic perspective, time’s arrow is a product of systems dynamics. Specifically, time is a product of the tendency of systems towards higher entropy, as was outlined at the beginning of this section. Specifically, the statistical dispersion of orderliness is the cause of the directionality of time. For a thermodynamic system, the statistical tendency towards higher entropy thus effectively constitutes the irreversible progression associated with time as a dimension. Time is in this sense not driven by an extra-systemic dimension but is itself the product of the thermodynamic tendency towards higher entropy—an offshoot of systems dynamics and not a background structure. This has wide-ranging implications; ¹⁸ but for present purposes, the crucial point is its implication for the relation between affective and temporal structure of living systems.

Understanding time as a product of the increase of entropy demonstrates an intrinsic interconnection between the respective entropic profile of any part of a thermodynamic system and its temporal structure. Insofar as temporality is defined by thermodynamics as a vector of intra-systemic dynamics, the temporal structure of the system cannot be represented as a relation to some independent background structure like a dimension of time. Instead, it may be represented by how its different subsets are maintained or not, along with the broader system, across entropic dispersion. In its minimal sense, then, temporal structure may be seen simply as extent in time, or existence across time: in a word, degree of diachronicity. Designation for lower entropy here corresponds to higher diachronicity, and vice versa. For example, parts of the system whose functional role is designated by lower entropy, will simultaneously have their temporal structure specified as high diachronicity.

One example is the distinguishing functional role of the organism as a repository for higher structural integrity, as seen above. The organism serves its vital functional role for the living system by its being designated for lower entropy, corresponding to its particular affective constitution. But this functional entropic profile of the organism simultaneously provides its essential temporal structure: namely as designated for high diachronicity. Conversely, the way in which the environment serves as a means for the living system is specified by its designation as a repository for higher entropy. And higher entropy, as seen above, corresponds to the increase of disorder, which is also the cause of the direction of time from the perspective of the system. In short, environments being designated for higher entropy corresponds to lower diachronicity. Accordingly, since temporality is a product of entropic dispersion, the temporal structure of any part of the system is continuous with its designation for lower or higher entropy, same as for affective structure.

In sum, both organism and environment are specified by their complementary entropic profiles. Affective structure is one way of characterizing these complements in terms of the cares and aversions of the system. But insofar as the affective structure of some part of the organism or of the environment is specified by an entropic profile, this is simply another way of characterizing its respective temporal structure. Because entropic increase is what constitutes temporality for the system, the designation of organism and environment by their complementary entropic role is also a specification of their respective temporal structure. Accordingly, understanding the organism and environment in terms of their respective affective structure (their significance as means for the living system) simultaneously specifies their respective temporal structure.

3.4 Implications of an entropy-based perspective

Approaching affective and temporal structure by way of a thermodynamically informed perspective shows both aspects emerging from the systemic dynamics for maintaining non-equilibrium. Before closing, this subsection will briefly outline a few caveats and as well as compare what has here bene outlined to the Jonasian account of structural temporality and affectivity from section 1.

First, it should be noted that, though entropy defines the minimal form of temporal and affective structure, this is not the whole story—especially when it comes to complex living system. The point here is not that everything reduces to their respective basic entropy-relative function, but that functions of more complex character emerge from out of a continuity with this basic structure. The temporal and affective structures of living systems arise in continuity with the same entropic designation. Whereas temporal structure is given in continuity with designations for lower or higher entropy conceptualized in terms of degrees diachronicity, affective structure is given in continuity with designations for lower or higher entropy conceptualized in terms of functional significances. The contribution of a thermodynamic perspective is that the emergence of the living system’s fundamental temporal structure, in terms of differential degrees of diachronicity, corresponds to the affective differentiation in terms of significance. Understanding living systems as relational non-equilibrium systems thus provides an explanation for the origin of structural affectivity and temporality and their fundamental interrelatedness. The entropic perspective taken up here supports a strong continuity thesis about minds and the fundamental organizational principles of living system in line with the proposals of enactive approaches.

Despite indebtedness to a broader Jonasian turn in enactive approaches to cognition, this thermodynamical interpretation does not attribute primacy to affectivity over temporality. As seen in the previous section, the Jonasian account’s conceptualization of the relation between affectivity and temporality in terms of two distinct steps (respectively, impulsion and execution) results in two key issues. First, it risks losing sight of temporal structure and, moreover, it implies a bifurcation between behavioral and intentional aspects of living systems that conflicts with key insights from contemporary cognitive neuroscience and enactive research. Here, it should be added that temporality and affectivity, co-emerge as ways of designating and differentiating parts of the living system in terms of salience or diachronicity.

Fundamentally, temporal and affective structures are constituted as ways of designating a differentiation between organism and environment as means for maintaining non-equilibrium. In this fundamental form, the affective differentiation of organism from environment in terms of significance corresponds to their temporal differentiation in terms of diachronicity. The significance of a given part of the system corresponds to a designation in terms of diachronic integrity. For example, what we normally designate by organism is simply an expression of a temporal horizon of privileged diachronicity corresponding to a mutually implied affective significance. This fundamental mutuality between basic affective and temporal structure provides a link between phenomenal iterations as purposive striving and temporal becoming. Those parts of the system identified for perpetuation will definitionally become inner states in both a temporal and affective sense. The intrinsic aspects of temporality and of striving “at the roots of life,” as put by Kiverstein (2017), and the reassessment of the affectivity (Berkovich-Ohana, 2017; Froese, 2020) are mutually expressed in this double temporal-affective structure. From the perspective of the living system itself, the principal recipient parts of systemic self-perpetuation, or striving, and its temporal becoming are two sides of the same coin.

As such, conceptualizing one as preceding the other would be a mistake. From a thermodynamic perspective, this would be akin to saying that one aspect of the entropic profile of the organism being designation for lower entropy somehow precedes the other aspect of this entropic profile being a designation for higher structural integrity across time. Lower entropy just is higher degrees of orderliness, which corresponds to a maintained structural integrity across time. The two statements: the organism holds a privileged position in terms of the care of the system (affective characterization) and the system strives to maintain the structural integrity of the organism (temporal characterization) have the same essential meaning. Regardless of what level such a differentiation may occur at, insofar as both are, in their most basic form, fundamentally the same (designation for lower or higher entropy), neither one can meaningfully precede or give rise to the other.

4. Conclusion

Research from both neuroscience and recent enactive approaches to cognitive science have suggested that the interconnection of affectivity and temporality may run deeper than hitherto anticipated. This paper has sought to clarify the relation between the temporality and affectivity as structural features of living systems through a thermodynamic perspective. In pursuit of such a clarification, the paper first outlined existing accounts of how temporality and affectivity should be regarded not in terms of special faculties, but of the inherent structural organization of minds and of living systems. This reconceptualization of temporality and affectivity raises the question of their mutual interrelation. The Jonasian account conceptualizes temporality and affectivity as distinct through interrelated moments, where affectivity holds primacy over temporality. Against this view, it was argued that taking affectivity as primary to temporality would be effectively to fall back on an inadequate view of temporality as well as of the relation between cognition and action. In place of this account, this paper has sought to provide the grounds for a way of viewing the relation between structural temporality and affectivity based on their role in maintaining thermodynamic non-equilibrium. In preparation for this way of understanding temporal and affective structure, each had to be related to the organism and environment of living systems conceptualized as complementary functional poles for maintaining thermodynamic non-equilibrium. Here, it was argued that each structure ought to be viewed in continuity with their fundamental meaning as designations for lower or higher entropy relative to a functionally determined organism or environment. As such, temporal and affective structures are, in their most basic form, different ways of referring to the same distinguishing entropic profile of, respectively, an organism or an environment.