Part 16 (1/2)

INDIVIDUATION.

The central thesis of this chapter is that the core property which links the selves of even the simplest life forms with that seemingly ineffable property that characterizes the human experience of self is a special form of dynamical organization: teleodynamics. What has not been made explicit, however, is that all teleodynamic processes are implicitly individuated, that is, they are closed in a fundamental sense with respect to other dynamical features of the world. This special form of closure is reflected in the phrase ”reflective individuation” used earlier, which I introduce to explicitly avoid using the prefix ”self-” (as in self-maintaining, self-organizing, self-reproducing) in defining the fundamental organizational logic of self. It also provides a more accurate and more explicit unpacking of the form of this relations.h.i.+p by implicitly invoking a mirror a.n.a.logy. Indeed, it might even be a.n.a.logized to mirrors reflecting one another and thereby creating a way of containing a perpetually reproduced image.

Another way to look at this closure is that it is the physical a.n.a.logue of a logical type violation in logic, such as that exemplified by the famous liar's paradox: ”This statement is false.” The concept of logical type is basically the relations.h.i.+p that exists between a whole and a part, or a cla.s.s and a member of that cla.s.s. The sentence above is interpreted as a composite whole by virtue of the interpretation of the parts (words) with respect to one another. But the component phrase ”This statement” refers to the whole of which it is a part and so a.s.signs the value of being false to the whole. The familiar result is that with each reading, one is enjoined to reread and reinterpret the sentence. This self-undermining statement can never be a.s.signed a final interpretation because the whole is constantly changing the reference of the parts and the parts are constantly changing the reference of the whole. The critical feature is of course that the whole is represented and reflected in the part. This is possible in a sentence because of the nature of symbolic representation. Since the reference of this phrase is not physically a.s.signed, but can apply to any object, there is nothing restricting its application to the sentence of which it is a part. In an organism, the relations.h.i.+ps are a.n.a.logous. Each component function contributes to the continued existence of the whole and the whole is required to generate each component function. In this sense, each functional feature embodies a trace of the whole individuated organism, reflecting the coherent influence of the whole and contributing to its future coherence. This is the essence of reflexive individuation: a compositional synergy, functioning to determine its const.i.tuents in a way that both embodies and reinforces their synergistic relations.h.i.+p. The whole/part hierarchy thus becomes inextricably tangled.

If this tangled dynamical logic is fundamental to organism self, then it should apply equally well to forms of self at other levels too, including human minds. However, these parallels need not be simple and direct. This is because the neural teleodynamics of mind is hierarchically nested within the vegetative forms of teleodynamics that const.i.tute simple cells and multicelled animal bodies. Mental self is both a higher-order form of self, and at the same time subordinate to the organism self. To rephrase this using the technical distinctions we developed in our earlier discussion of emergence, neural teleodynamic processes dynamically supervene on what might be called the vegetative teleodynamics of the organism, and organism self dynamically supervenes on cellular self, though in different ways. Even the simplest bacterium is organized as a self, with emergence of ententional properties and possibly a primitive form of agency in the ability to propel itself (e.g., with a flagellum). However, the intentionality and subjectivity which exemplifies species with complex brains involves higher-order properties that emerge from a distinctive higher-order level of reflexive dynamics const.i.tuted by the interactions among the vast numbers of vegetative teleodynamical selves that are neurons.

This vegetative form of self exhibits some very general organizational principles, which are necessary and sufficient to explain the emergence of end-directed and informational relations.h.i.+ps from simpler components lacking these attributes. But why must a system exhibiting teleodynamic organization be an individuated unit? This is not the case, for example, with thermodynamic or morphodynamic processes. They may be physically boundable, but it is only a contingent boundedness. Organisms also typically are materially bounded, but in addition their boundedness is intrinsic to their dynamics. It is implicit in the closed reciprocity of organism functions. As a result, physical boundedness may be ambiguous in many organisms or at certain stages in their development. The necessary interdependence of organism structures and processes implicitly determines an individuated system. This intrinsically generated individuation also determines a self/other distinction, which need not be an artifact of material discontinuity or containment within a membrane. So, while biological self and other are commonly distinguishable on either side of some physical interface-a membrane, cell wall, or skin-these are only convenient means of physically embodying this otherwise purely dynamical distinction.

SELVES MADE OF SELVES.

The primacy of dynamical boundedness over material boundedness becomes more evident as we ascend in level of biological and mental selfhood. And when we reach the level of a human subjective self, even the concept of boundary makes no sense, despite the fact that the reflexive closure of subjectivity is unambiguous.

With the evolution of ever more complex forms of organisms, the recursive complexity of self has also necessarily become more highly differentiated. Multicellularity offers a case in point. Multicelled organisms all develop from single-cell zygotes. This initial single cell self-reproduces vast numbers of genetically identical offspring cells-self copies-that at early stages of embryogenesis still retain some degree of autonomy. By remaining in contact with one another, maintaining a molecular and topological trace of their relative positions, and sending identifying molecular signals to one another, this local society of cellular twins begins to differentiate and cellular-level autonomy decreases. Each gives up progressively more of its autonomy to the growing whole embryo. Cellular-level dynamical reciprocity is thus progressively simplified, and intercellular forms of reciprocity begin to take its place. One level of individuation is sacrificed so that a higher level of compositional individuation can form. Again, what determines this transition in level of self is not the generation of an exterior skin, but rather a change in dynamical reciprocity. In this way, local cl.u.s.ters of similarly differentiated populations of cells, forming organs, begin to play an a.n.a.logous role to the various interdependent cla.s.ses of molecular processes within a cell. Developing a skin or bark or sh.e.l.l serves a different purpose. It protects the now more distributed reciprocity from extrinsic disruption.

Of course, protective encas.e.m.e.nt is a nearly ubiquitous feature of organism design-whether for viruses, bacteria, amoebas, plants, or animals-because reciprocity is always potentially disruptable by the intrusion of extrinsic influences. Dynamical reciprocity, without which there can be no teleodynamics, is therefore forced to persist in the context of mutually exclusive requirements with respect to the external non-self world. Because it is dynamical, it is dependent upon extrinsic energy and material; because it is a form of reciprocal dependency, it is dependent upon being isolated from aspects of the non-self world that might disrupt this delicate reciprocity. For this reason, the evolution of highly specialized bounding surfaces, which are also selectively permeable, is one of the most important loci of evolutionary differentiation. Whether cell membranes with their elaborate constellations of receptor and transporter molecular complexes linking inside and outside, or animal body surfaces with their mult.i.tudes of receptor types and motor organs enabling them to find food and mates or avoid predators, this interface is where the self-other distinction mostly gets negotiated. It is just not what determines self. So, although our attention tends to be drawn to these boundary interfaces when focusing on what const.i.tutes self, this interface is better understood as an adaptation to better preserve the self already there.

The critical but contingent relations.h.i.+p between selves and physical boundaries complicates the identification of biological self. Individual cells in your body are each physically bounded by a membrane within which the reciprocal processes essential to self-maintenance take place. But they are also critically incomplete as well. Unlike free-living cells, somatic cells have become co-dependently parasitic. Their integration into a larger self has enabled them to forgo the adaptations to the variable environments that an autonomous cell must encounter. One of the most fundamental is reproduction. Many of the cell types in your body are terminally differentiated, which means they cannot be modified to be any other kind, and many of these are non-reproductive, that is, they will never again divide. Apparently, the molecular apparatus that must be maintained in order to support this ma.s.sive metabolic transformation would be a significant impediment to the terminally differentiated function of this cell. Thus differentiated neurons and muscle cells, for example, have either redeployed some of this apparatus for other purposes or suppressed its generation altogether. They still retain one feature of organism self but have sacrificed another. The metabolic self (so to speak) of these cells is bounded in the cell membrane, but that feature of biological self which maintains this ultimate hedge against the ravages of entropy-duplication-has been s.h.i.+fted to the whole organism.

Of course, the locus of individuated self is also ambiguous in other biological contexts. Lichens are the result of a co-dependent symbiosis between a fungal and algal species, neither of which can exist without the other. Their reciprocal co-dependence is also guaranteed by the degradation in each species of adaptations for autonomous living. The lichen is therefore an individual defined by this reciprocal co-dependence, and not by genetic h.o.m.ogeneity. This is not really an exceptional case in biology: all eukaryotic organisms share the trait in a very basic form, including us. The mitochondria-the tiny bacterial-shaped loci of oxidative metabolism in every plant and animal cell-are the distant ancestors of a once free-living bacterial organism that evolved to become an endo-symbiont to another larger-celled form. This is not merely reflected in their characteristic beanlike structure, but also in the fact that they contain and reproduce within each cell using an enclosed circular bacterial chromosome, whose DNA sequences place all mitochondria (from plant or animal) well within the bacterial lineage. Thus we too are characterized by dual genomes with separate origins.2 Our current cellular-level individuation is in this way characterized by a synergistic reciprocity that developed between these once separately closed forms of teleodynamic unities.

Such self-components (somatic cells) integrated into higher-order self units (organisms) are each internally sustained by highly complex networks of synergistically reciprocal morphodynamic processes. They are individuated selves by virtue of the level at which there is circular closure of this morphodynamic network. This closure not only creates a distinct level of individuation but also a distinct locus of teleodynamics. I have designated each of these partially autonomous, partially dependent levels of individuated teleodynamics a teleogen, as distinct from an autogen, which is fully autonomous and simple. In the complex biological and mental worlds of the present state of life on Earth, teleogenic structures are the norm, as evolution tends to generate highly entangled forms of teleodynamic processes, given sufficient time. This is not because evolution is itself a kind of final causal process, but rather because there is no limit to how teleodynamic processes can become entangled with one another. This also leaves open the possibility that the different teleogenic units const.i.tuting a complex organism can come into conflict.

Tracing the way that higher-order forms of organism evolve was the topic of the last part of the previous chapter. There we noticed that each s.h.i.+ft to a higher-order form of individuation was typically a.s.sociated with loss of lower-level autonomy and the serendipitous self-organization of higher-order synergies. What evolves in these cases are multiple levels of self-built-upon-self, with the higher-order reciprocities and synergies emerging as a result of the degradation of certain self-features of the lower-level component selves. Because of this, the remaining lower-level teleodynamic characteristics are those most consistent with the higher-order teleodynamics. Teleogens composed of teleogens in which lower-level degradation is present are thus common. In the case of mitochondria and their ”host” eukaryotic cell, for example, both the nuclear genome and the mitochondrial genome are partially ”reciprocally” degraded, so that neither can persist without the other, but for most functions they remain relatively modular and individuated in their functions. This tendency for modularity, implicit in the nature of teleodynamics, is what makes complex multi-leveled selves possible. Without it, a complexity catastrophe would be inevitable-too many components, needing to interact in a highly constrained manner in a finite time, despite vast possible degrees of freedom-setting an upper limit on the complexity of self.

Because self is defined by constraints, not by particular material or energetic const.i.tuents, it can in principle exist in highly distributed forms as well. Thus a termite colony may involve millions of individuals and many generations of turnover, but only one reproducing queen. In reproductive and evolutionary terms, only the whole functioning colony is a reproducing organism, and the ”self-” of the colony is quite ambiguously bounded in s.p.a.ce or material and energetic usage, especially when vast numbers of individuals are foraging independently in the surrounding territory. Thus self, too, may become highly diaphanous at higher emergent levels, with more variable degrees of individuation and correlation with physical boundedness emerging at progressively higher-order levels of self.

These many features of teleogenic hierarchies are of course relevant to mental selves. Mental self is not a composite self in the same sense as is a multicelled organism body. Brains are composites of vast numbers of highly interdependent cells-neurons and glia (the ”support cells” of the nervous system). And each neuron is extensively interconnected with other neurons. Brains evolved to enable multicelled animal bodies to move from place to place and intervene in the causality of extrinsic conditions, thereby altering the body's relations.h.i.+p to its local environment. Brains are in this respect part of the boundary that mediates between the teleodynamics intrinsic to the organism and the dynamics of its external world. So, in certain respects, it might be appropriate to compare brains to the specialized molecular pores, signaling molecules, and actuators (like flagellar motors) that span the membranes of cells and mediate inside/outside relations.h.i.+ps. They are part of the boundary interface that continually creates and demarcates self. But unlike these cellular-level interface mechanisms, brains mediate the self/other distinction by using the dynamics of self itself.

NEURONAL SELF.

Despite the current focus on consciousness, mental self is subordinate to and nested within the more general form of self that is characteristic of all living organisms. This is made self-evident by the fact that although the unconsciousness of anesthesia can temporarily interrupt this experience, the continuity of self persists across such gaps, so long as the body remains alive and the brain is largely undamaged. Even where there has been profound memory impairment, as in victims of Alzheimer's disease or hippocampal damage, though ident.i.ty may be compromised, the sense of consciousness and agency still persists. Our worries about death, and our comparative unconcern with the state of unconsciousness, or even amnesia, thus provide evidence that we intuitively judge the self of Descartes' cogito to be subordinate to the self of life in general. Nevertheless, the experience of this self is the result of the way that organism self pervades and organizes neural processes.

Brains are organs which evolved to support whole organism functions that are critical to persistence and reproduction. They are not arbitrary, general-purpose, information-processing devices. Everything about them grows out of, and is organized to work in, service of the organism and the teleodynamic processes that const.i.tute it. Animal physiology is organized around the maintenance of certain core self-preservation functions on which all else depends. Critical variables-such as constant oxygenation, availability of nutrients, elimination of waste products, maintenance of body temperature within a certain range, and so forth-all must be maintained, or no other processes are possible. Sensory specializations, motor capabilities, basic drives, learning biases, emotional response patterns, and even the structure of our memories are ultimately organized with respect to how they support these critical core variables. Additionally, the reproductive capacity, which is a ubiquitous correlate of having evolved, is also part of the larger teleodynamic background that gets re-expressed as neurological self, and similarly insinuates biases into these basic neuronal processes.

So, as a critical mediator of the self/other interface, a brain must be organized around this constellation of processes that const.i.tutes the teleo-dynamics of organism self. The reciprocity and interdependence of the various physiological processes that sustain the organism thus get recapitulated as core organizing principles const.i.tuting neurological function. For the most part, however, the monitoring and regulation of these core bodily functions is automatic, and maintenance of them is relegated to the physiological a.n.a.logues of thermostats and guidance systems, that is, teleonomic mechanisms. Nevertheless, these processes must also be re-represented to a higher-order adaptive process in service of mediating action within and with respect to the environment. So the vegetative self of the organism must be triply embodied: first in the cellular-molecular relations.h.i.+ps that form the most basic organism teleodynamics; second in higher-order automatic neuronal regulatory systems; and third in the way that changes in these regulatory processes or in the values of the underlying physiological variables alter the yet higher-order adaptive activities of the brain that mediate between the vegetative teleodynamics and the world of extrinsic possibilities. It is this third level of re-re-represented organism teleodynamics that is the substrate of the subjective self.

Neural self is further complicated by virtue of its role as inside/outside mediator. Brains evolved in animals to generate alternative virtual worlds and virtual futures. In order to be able to favorably change the contexts within which the organism finds itself, brain mechanisms must be able to model an organism's surrounding conditions and also to model the possible outcomes of acting to modify those conditions. To do this, an animal must be capable of simulating more than just the moment-to-moment changing relations.h.i.+ps between internal dynamics and external conditions. It must also be able to predict the possible consequences of its own interventions. Of course, depending on the predictability of the environment and the complexity of the organism, this modeling capacity may need only a small constellation of relatively fixed alternative responses. But where both the environment and the organism are complex, this may require elaborate, open-ended means for generating conditional scenarios. In such complex cases, it is critical to also include the capacity to simulate the teleodynamic processes that produce these adaptive behaviors and generate these scenarios. In social species, this can reach quite convoluted levels of detail. But because of the intrinsically recursive nature of behaviors that change external conditions, even modestly complicated brains need to include some self-referential features.

Thus it is inevitable that having a brain should also entail the generation of a form of teleodynamic relations.h.i.+p that is partially organized with respect to itself as environment. This higher-order form of teleodynamic causal circularity creates an entirely novel emergent realm of self-dynamics. It helps to explain why being an organism with a complex brain inevitably includes a doubly reflexive organization with respect to itself. This self-referential elaboration of teleodynamic logic is therefore one level more convoluted than any autogenic process. This predictive and projective function creates a more open-ended form of individuation, which must be able to generate a diverse range of possible self-environment scenarios. This premium on the flexible generation of possible futures (and thus purposes) makes the term teleogenic particularly apt for such a level of teleodynamic process.

SELF-DIFFERENTIATION.

The development of self emerges in a process of differentiation. The self that is my entire organism did not just pop into the world fully formed. It began as a minimal undifferentiated zygote: a single cell that multiplied and gave rise to a collection of cells/selves which by interacting progressively differentiated into an embryo, a fetus, an infant, a child, and eventually an adult organism. Similarly, it is difficult to imagine one's subjective self just popping into existence fully differentiated. By the very nature of its thoroughly integrated and hierarchically organized form, it would seem to demand a bottom-up differentiation in order to arise. But if so, then this also suggests that the moment-by-moment subjective sense of self, as well, is only the most differentiated phase in a sort of micro-differentiation process happening continuously and in the s.p.a.ce of seconds.

This is consistent with introspective experience. There are times when we are only dimly aware of our memories, our intentions, or the surrounding stimuli. For example, on waking from a sound sleep, we experience a sort of ascent into differentiated awareness, and a graded ”booting-up” of our more critical and goal-directed faculties. The early phases of this process involve only the incorporation of basic physiological and somatic factors into awareness, and are in this sense largely undifferentiated forms of self. Only after we are fully awake, beginning to a.s.sess our immediate surroundings, and remembering the habitual activities, demands, and plans that attend this time of day and social condition, does our mode of self become fully differentiated. But even as one experience gives way to another and one activity gives way to another in the course of awake experience, each new focus of attention and intention must differentiate anew to replace a former, more or less differentiated phase of awareness. In this sense, each change of focus is a mini-recapitulation of waking anew. There is no deep discontinuity because the least differentiated level of self changes little from moment to moment; but even so, one characteristic of severe anterograde amnesia (in which the victim cannot consolidate new memories) is a constantly recurring sense of ”just now being awake for the first time.”3 In summary, then, it is my hypothesis that the subjective self is to be identified with this locus of neurological teleodynamics, which is variably differentiated at various stages of life and alertness, and which in its most differentiated form can include itself as recursively represented and projected into a simulated virtual world. Because teleodynamic processes depend on lower-order morpho- and homeodynamic processes, these too must be taken into account in a full theory of neurologically generated subjective experience (a topic addressed in the next chapter). And because these are emergent dynamical processes, all rely on constant exuberant metabolic activity, and are always in some stage of differentiation or dedifferentiation that takes time to unfold.

Additionally, as is also the case with simple autogenic systems, because a teleodynamic system is self-generating, self-reinforcing, and self-similarity maintaining, it can serve as a reference dynamic against which all other dynamical tendencies and influences that affect it are contrasted. Their distinction as non-self is implicit in their tendency to initiate the generation of contragrade dynamical teleodynamic processes. This orthograde/contragrade teleodynamic distinction thus defines the dynamical boundary of self. The minimal form of this teleodynamic organization is also at the core of all neurological functions, where it can be as undifferentiated as a simple autogenic process, and likewise provides the most basic self/non-self distinction by virtue of the contragrade dynamics of adaptive physiological processes. However, this teleodynamic organization is progressively re-represented and differentiated within brain systems that are progressively more entangled with external receptors and effectors. Because of the intrinsically conservative self-similarity-maintaining nature of teleodynamic processes, each level of teleodynamic activity is an effective locus of self, and is that with respect to which otherness is implicitly marked. Each locus of teleodynamic neural activity is also the dynamical ”substrate” which differentiates and ”evolves” moment by moment with respect to a complex environment of sensory ”perturbations,” present and remembered.

In this sense, the unity of consciousness may be more mercurial than commonly imagined. Different loci of teleodynamic activity at the same level may develop in parallel and come into compet.i.tion as they differentiate and propagate to recruit additional neurological resources. Thus the differentiation of self may also involve a Darwinian component (also discussed in the next chapter). The often quite sophisticated alter egos that we find ourselves interacting with in dreams, and who can often act in unexpected ways, suggests that in this state of consciousness, there may be no winner-take-all exigency. In dreams, all action is virtual and thus need never be finally differentiated; but when awake and enjoined to behave by real-world circ.u.mstances, action depends on a winner-take-all logic to produce a single integrated action. So the unity of waking conscious experience may in this respect be a special case of a more pluralistic self-differentiation process.

THE LOCUS OF AGENCY.

Perhaps the most enigmatic feature of self is its role as agent: as the locus and initiator of non-spontaneous physical changes in the world around it. This is often confused with the age-old problem of explaining the possibility of free will in a deterministic world. However, it is different in a number of important respects. Self as agent is indeed what philosophers struggling with the so-called free will paradox should be focused on, rather than freedom from determinate constraint. Determinate causality is in fact a necessary condition for the self to become the locus of physical work. An agent is a locus of work that is able to change things in ways more concordant with internally generated ends and contrary to extrinsic tendencies.

Approaching the self-dynamics of mental agency using this same framework, we need to look to the closure of the teleodynamic constraint generation process for the locus of the capacity to do self-initiated work. For the simplest autogenic process, this closure is const.i.tuted by a complex synergy between morphodynamic processes that makes possible both the generation of constraints and also their maintenance and replication. The teleodynamics that distinguishes the agency of organisms from mere physical work is a product of this closed reciprocity of form- (i.e., constraint-) generating processes. Specific forms of work are made possible by the imposition of specific forms of constraint, and the way this channels spontaneous change, via the expenditure of energy. So this defining dynamic of organisms amounts to the incessant generation of the capacity to perform specific forms of work to alter the surrounding milieu in ways that are determined by this locus of teleodynamics, irrespective of extrinsic causal tendencies. This persistent capacity to generate and maintain self-perpetuating constraints is therefore at the same time the creation of a locus of the capacity to do self-promoting work.

Evolution can be seen as a process that has vastly complicated both the nature of these constraints and the capacity to utilize them as means of initiating specific forms of work-work that aids the persistence and further evolution of these capacities. As new forms of teleodynamics evolve, they bring new capacities to perform work into being-new options, correlated with ever more diverse extrinsic influences. In this way, as evolution has given rise to organisms that embody vast webs of constraints in their internal dynamics, and specifically with ever more diverse means of interacting with their surroundings, they have increased the ways in which they are able to impose these or complementary constraints on the dynamics of external events and relations.h.i.+ps. So, to again describe this in the negative, the evolution of increasingly complex forms of constraints-absences-has given rise to increasingly varied ways to impose constraints on the world with respect to these internal constraints. In this sense, the source of agency can be somewhat enigmatically described as the generation of interactive constraints which do work to perpetuate the reciprocal maintenance of the constraints that maintain organism self.

This view of self-agency, defined in terms of constraints, may seem counterintuitive because of our conviction that the emergence of life and mind has increased, not decreased, our degrees of freedom (i.e., free will). Increasing levels and forms of constraint do not immediately sound like contributors to freedom. In fact, however, they are essential. What we are concerned with here is not freedom-from, but freedom-to. What matters is not some disconnection from determinate physics, but rather the flexibility to organize physical work with respect to some conserved core dynamical constraints. This is not a breakdown of causal efficacy; in fact, just the opposite. Being an agent means being a locus of causal efficacy. Agency implies the capacity to change things in ways that in some respects run counter to how things would have spontaneously proceeded without such intervention. It also implies that these influences are organized so that they support the persistence of this capacity, and specifically the persistent self-generating system that is its locus.

What we are concerned with here is not some abstract conception of causality but rather the capacity to do work, to resist or counter the spontaneous tendencies of things extrinsic to the teleodynamics that creates self. The evolution of our higher-order capacities to create and propagate ever more complex and indirect forms of constraint-from the self-organizing processes that build our bodies to the production of scientific theories that guide our technologies-has in this way progressively expanded the capacity to restrict sequences of causal processes to certain very precise options. The ability to produce highly diverse and yet precise constraints-absences-thus makes possible a nearly unlimited capacity for selves to intervene in the goings-on of the natural world.

EVOLUTION'S ANSWER TO NOMINALISM.

But where does the ”freedom” come from? Clearly, it is not freedom from deterministic involvement in the world, because this would preclude the capacity to do work. The answer to this question is ultimately related to the cla.s.sic realism/nominalism problem. To see this, it is first necessary to recapitulate bits of the critique of the Realism/Nominalism debate in philosophy that we initially dealt with in chapter 6.

The cla.s.sic nominalistic view is that being a member of a general type or a categorized phenomenon, such as a whirlpool or a member of a species, does not in itself have any causal significance over and above the unique and distinct individual physical attributes of that particular instance. Exhibiting a general form does not, according to this view, have any independent causal status. These generalities and similarity cla.s.ses are merely mental constructions, due to a necessary simplification that is implicit in the nature of mental representation.

By recognizing, however, that in the physical world the a.n.a.logues to general types can be determined negatively, that is, in terms of constraints, it becomes possible to understand physical causality negatively as well. This is because constraints can propagate through physical interaction. Or to state this negatively, degrees of freedom not actualized do not tend to propagate during physical interactions. Moreover, as the discussion of work has further clarified, all non-spontaneous change (efficient cause) is a function of the coupling of constraint and constraint dissipation (i.e., the release of energy). So general tendencies, understood in this negative sense, can indeed be the loci of physical causality, because work both depends on and propagates constraints. General properties understood in this negative sense are, then, the causal determinants of other general properties.