Deacon’s outstanding but challenging book concerns two of the most intractable scientific questions: how did life arise from non-living molecules, and how did conscious intelligence and agency arise from mechanistic natural forces? Answers to both questions place seemingly impossible demands on established science. Science must assume that there is a uniform causal structure to nature that operates in an unbroken chain linking the smallest subatomic particles to the largest socio-political constructions built by human beings. Since these constructions require human thought (which Deacon examined in his previous book, The Symbolic Species) and thought is symbolic and intentional, the human world appears to operate on quite different causal principles (teleological rather than mechanical). Natural scientists have most often tried to preserve the causal uniformity of nature at the expense of preserving and explaining the unique texture of the symbolic dimensions of human reality. Since the 17th century, reductionism has ruled natural science. While reductionism has led to spectacular technological achievements, no one has yet successfully provided a reductionist account of consciousness and agency that convincingly explains rather than explains away the properties that distinguish them as consciousness and agency. Deacon titled his book Incomplete Nature as a challenge to scientists to acknowledge that living systems and conscious agents are characterised by powers that non-living systems do not have and to meet that challenge by working out a non-question begging explanation of the mediations through which life emerged from non-life and consciousness emerged from unconscious elements.
The books’ brilliance is rooted in Deacon’s honesty and originality. He accepts the principle of causal uniformity, even thought its operation would seem to to rule out that which he devotes his considerable scientific and philosophical powers to explain: the reality of the teleological powers of self-conscious life. Eliminative materialist reductionism is unsatisfactory because it simply denies the reality of that which a complete natural science must explain: the ability of living beings, and especially self-conscious agents, to initiate action and bring about states of affairs that would not exist without their goal-seeking activities. On the other hand, the best scientific alternative to reductionism, emergentism, tends to bog down in the other direction. If reductionist attempts to save causal uniformity cannot explain the emergence of the unique powers of life and conscious intelligence, the existing emergentist theories cannot square their accounts with the causal uniformity of nature. Existing emergentist theories have not yet adequately explained by the mediations that enable the phase transitions between atomic and molecular structure and functional biological systems, and functional biological systems and intelligent agency. Instead of detailed explanation of these transitions, emergentists tend to invoke exotic and under-explained ideas of “top down causality” and slogans like “the whole is greater than the sum of its parts.” Deacon does not claim to have developed a fully worked out and empirically adequate explanation of these critical transitions, but he does think that he has created a novel approach that solves some methodological problems and opens to door to the empirical work necessary to one day arrive at complete and coherent solutions.
Deacon’s approach is materialist– one might even say dialectical, without meaning anything more than “dynamic” by that loaded term. The unique powers of living beings cannot be understood if they are treated as reified wholes greater than the sum of their parts. Instead one must pay attention neither to the whole nor the parts but the interactive dynamics that distinguish living beings from non-living material systems. The distinguishing powers that life-forms display are high level analogues of lower order self-organizing processes that are explicable by reference to the most basic physical forces. Deacon’s account preserves causal uniformity but avoids the pitfalls of reductionism. There is no one to one correlation between a thought and a material brain state that would allow the scientist to conclude that the thought is nothing but the brain state. The brain state depends upon thermodynamic work and the thought depends on the brain state, but it instantiates a new form work that Deacon calls “teleodynamic.” Teleodynamic systems are defined, paradoxically, by the absent state that they represent to themselves. Thoughts represent absent objects and posit goals about future states that the organism then tries to bring about. These “absential properties” are the key to one day constructing a complete and consistent explanation of how mind emerged from matter.
Deacon’s argument is too complex to reconstruct completely and too difficult for me, a non-scientist, to understand in every detail. His account draws on mathematics, physics, information theory, chemistry, bio-chemistry, evolutionary biology, and neuroscience and was built up over a decade working with a team of specialists from these different areas. Even readers with a science background will be challenged to understand every step of the argument; humanist philosophers like me, drawn to the book because of its non-magical explanation of human origins, will often find themselves at sea. However, since Deacon writes as clearly as one might hope about these issues, if they pay attention and are patient, non-scientists can understand the argument well enough to grasp the limits of competing explanations and the merits of Deacon’s alternative. Whether it proves correct is for future scientists to decide, but anyone interested in these problems will come away from the book better versed in what a true explanation of these existential as much as scientific problems will have to contain.
Deacon begins by reviewing the well-known limits of reductionist explanations of life and mind. As far back as Aristotle’s critique of atomism philosophers have stressed the difference between living and mechanical systems: living entities can initiate action whereas mechanical systems require an impetus from outside. “There is a “discontinuity of causality implicit in human action” that parallels a related discontinuity between living and non-living processes. Ultimately both involve what amounts to a reversal of causal logic: order developing from disorder, the lack of a state of affairs bringing itself into existence, a potential tending to realize itself. But compared to the way things work in the non-living, non-thinking world, it is as though a fundamental phase change has taken place in the dynamical fabric of the world.” (21) This difference is the touchstone of all idealisms (and non-reductive materialisms). Criticising reductionism has proven far easier than providing satisfying non-reductionist explanations. Idealist explanations, from ancient Greece to Descartes, simply beg the question: they assume the existence of a non-physical substance with the power to freely initiate actions but do not explain how its existence is possible in a world of matter and energy. Appealing to the eternity of forms (Aristotle) or divine creation (Descartes) is not scientifically satisfying since it does nothing more than assert whatever conclusion the abstract coherence of the theory requires. But theories must be empirically verifiable as well as internally coherent.
In order to advance beyond the impasses of idealism, reductionism, and standard emergentist theories Deacon makes a bold and counter-intuitive move. The problem with idealism is that it is question-begging, and reductionism and emergentism face the same problem from opposed sides: trying to explain consciousness as some thing, either “nothing more” than brain states or, from the other side, some unique expression of those states whose properties can be described but whose connection to physical reality remains unexplained. Deacon tries a different tack: consciousness is not a thing at all, but must be understood as an “absential” property. Absential properties are states which can produce effects in the physical world because they seek to correct from an absence of some sort. When you are hungry, you initiate a sequence of actions to find food; the conscious desire for food is a desire for that which is not present. The absence of the food is the cause of one’s working out a sequence of actions to attain it. “My counterintuitive hypothesis is that whenever we recognize that a system exhibits ententional properties, it is not because of something added to the physical processes involved, but rather quite literally because it depends on the physical fact of something specifically missing from that object or process.”(43) Ententional properties are “all phenomena that are intrinsically incomplete in the sense of being in relationship to, or constituted by, or organized to achieve something non-intrinsic.”(27) This counter-intuitive move does not explain how the ententional property (the action-causing absence) emerges from physical functions at more basic material levels, but it helps free the search for an explanation from a search either for the basis of consciousness to which its phenomenological forms can be reduced or the sui generis emergent property to which basic physical forces give rise.
Mechanical causality transfers the force of one object with momentum to another object with momentum. The pool player strikes the cue ball with the cue, it hits the 8 ball at a definite angle, and the 8 ball moves along a predictable vector into the pocket. One material substance transfers energy to another material substance causing motion. But the decision of the pool player to strike the cue ball is distinct. They must imagine the shot before they actually make it. There is brain activity involved in the imagination, as we will see, but the idea is of a state which does not yet exist (the 8 ball going into the pocket) and motivated by a desire which can only be understood in relation to a symbolic universe of rules (winning the game). The mechanical sequence of causes is therefore caused by the idea of a future state that does not yest exist. Newtonian mechanics is indifferent to time: we can use Newton’s laws to predict future eclipses and we can use them to work out when eclipses must have occurred even in the past before there were human observers. Actions causes by ententional forces are not similarly indifferent to time: they bring about future states which would not have occurred simply by the operation of mechanical forces.
Although conscious life-activity reverses the causal relationship and basic thermodynamic tendencies at work in non-living, unconscious material reality, any acceptable scientific explanation must be compatible with quantum and mechanical physical forces. Unless the mediations that lead from quarks to atoms, atoms to organic molecules, and organic molecules to self-conscious living organisms can be worked out in detail, we will be thrown back on magical (idealist) explanations or quasi-magical substance-emergentist theories. Substance emergentism looks for the special sort of thing that consciousness is. The problem that it runs into is that it maintains without explanation of how that “emergent transitions involve a fundamental discontinuity of physical laws.”(159) Deacon takes the leading philosophical critic of this form of emergentism, Jaegwon Kim’s question seriously: “Why is there anything except physics?” (165) Deacon’s attempt to provide a non-question-begging, non-magical, non-dualist answer to this question forms the empirical heart of his argument (and also poses the most serious challenge to the limits of the understanding of non-experts).
Deacon argues that all the purportedly irreducible causal powers of life are ententional, but also that each emerges from and is explicable by lower order physical systems operating mechanically. Even at the simplest levels, natural processes display powers of spontaneous structure formation. The most basic natural process is entropy– the running down of energetic systems from highly ordered to disordered states. Deacon’s argument is that the roots of the highly organized structures of living systems whose existence depends upon their ability to constrain entropy (at least over short periods) are built up from the second law of thermodynamics. Amazingly (to my scientifically untrained mind) coherent structures emerge even in the simplest thermodynamic systems provided that there is a constant supply of energy.
Deacon gives the example of Benard cells: hexagons that form in a thin layer of liquid constantly heated to a certain uniform temperature. To the chagrin of intelligent design theorists going back to William Paley, Benard cells are geometry without a geometer. They naturally, spontaneously form because it just happens to be the case that hexagons are the most efficient shape through with the heat energy can be dissipated. (252) The law of entropy determines that the heat must be dissipated, so this most basic thermodynamic process is the source of the structure that emerges. Thus, all one needs for the formation of coherent structure is heat, the second law of thermodynamics (which states that the system’s energy must run down, its heat be dissipated) and geometry. So long as there is a heat source, these structures will reproduce themselves.
Of course, it is a long way from hexagons formed to dissipate heat to conscious intentional action, but these purely physical processes are the basis of all high-level structures. What they prove is that structure is a function of the most basic processes in nature. Once we have these purely physical structures, other possibilities– which seem magical, if viewed in isolation– become more probably. The shape of a protein is so complex it seems impossible unless an infinite intelligence designed it. But when we understand that nature is a billions years old dynamic energetic system that spontaneously gives rise to coherent but simple structures, we can start to look for mediating processes and not a magician or divine designer. The mediating processes explain how greater complexity is a function of the addition of elements to the basic processes of spontaneous structuring.
At the root of life and consciousness lies the homeodyanmic forces of thermodynamics. Energy naturally runs down into disordered states, unless constrained by a countervailing natural force. The result of the interaction between certain countervailing natural forces and the homeodynamic force of entropy is “morophogenesis.” Morphogenesis is the simplest type of structure formation. Benard cells are a purely physical example of morphogenesis, but the more relevant for the explanation of the emergence of life occur when we examine the spontaneous behaviour of more complex chemical systems. Crystal formation could be thought of as a link between the spontaneous geometry of Benard cells and organic chemistry: crystals form spontaneously into regular structures, but they lack the capacity for deliberate self-maintenance that characterises life. Life not only replicates itself, it maintains an environment that allows it to replicate itself and for this certain organic structures are necessary. Just as in the case of Benard cells and crystals, it turns out the more complex molecular systems can form themselves into useful structures (like tubules and other self-enclosed shapes that create a spaces in which higher-order organic functions can develop). These enclosures, so to speak, are absolutely essential to the emergence of life, but they can be explained by the way in which the molecules involved naturally shape themselves if a constant supply of chemical input is maintained. Deacons calls the structuring activity that creates functional whole morphodynamics: “the dynamical organization of a somewhat diverse class of phenomena which share in common the tendency to become spontaneously more organized and orderly over time due to constraint perturbation but without the extrinsic imposition of influences that specifically impose the regularity.”(237) In simpler terms, morophodynamics organize elements into regular, useful structures without the intervention of any outside organizer. Morphodynamics arise from homeodynamics and homeodynamics arise from thermodynamics. The causal uniformity of nature is not violated by the increase in self-organizing complexity.
Whew!
Got that, class?
As I noted, the book is challenging and I cannot say that I fully understand the details, but I do think I have grasped the basic lines of development that Deacon presents. If the most basic laws of physics not only allow for but explain very simple, self-organizing processes, then the emergence of life, the most complex self-organizing, self-maintaining, ententional, system, while still supremely difficult to explain, is at least not mysterious. Life is the most complex example of a natural system that Deacon calls an “autogen.” “An autogen is a precisely identifiable source of causal influence because it generates and preserves dynamical constraints — the basis for thermodynamic work.” (311) The simplest are not remotely conscious but they organize molecular structures in a self-perpetuating way- they are the physical mediation between life and not-life.
Life is not only self-organizing and self-maintaining but also (above the very simplest life-forms), self-directing. Whereas purely physical homeodynamic systems maintain a steady state, living things maintain a steady state by performing conscious work. Deacon thinks of work not as creative self-externalization (along Hegelian-Marxist lines) but as the imposition of constraints on systems that would otherwise be run down by entropy. Left to itself, a field would become overgrown with weeds. Agricultural work constrains this spontaneous outcome, but on the basis of ententional powers to observe and understand the pattern of weed spread and work out a practical series of steps to prevent that from happening. These powers are the functions of organs that are the products of 3 billion years of evolution. Natural selection preserves life-supporitng functional wholes, but the more basic structures which underlie functional organic wholes developed out of spontaneous morphogenetic patterns that emerge in material nature.
Natural selection explains how the simplest self-maintaining life-forms have developed into socially self-conscious human agents. The real question concerns how that logic of self-complexification got going in the first place. “Although natural selection offers a powerful logic that can account for the way organisms have evolved to fit their surroundings, it leaves out almost all the mechanistic detail of the process involved in generating organisms, their parts, and their off spring.”(422) Deacon does not claim to supply all of the necessary mechanistic detail, but he helps the process along by reinterpreting evolutionary processes according to his “work as constraint” metaphor. “Evolution is not imposed design, but progressive constraint.”(427) As he explained in discussion of autogens, spontaneous morophological processes can generate order and structure by purely physical means. Natural selection in essence ‘captures’ certain morphological structures– organic molecules and the more complex systems they spontaneously formed– and preserves them. Prior to the evolution of DNA, these spontaneous morphologies formed the molecular basis of life: “Evolution in this sense can be thought of as a process of capturing, taming, and integrating diverse morphodynamic processes for the sake of their collective self-preservation.” (427) If Deacon’s picture is correct, then the precise steps by which life and consciousness emerged are no longer mysterious or require exotic causal powers to explain. “So the first organism wasn’t a product of natural evolution. The constellation of processes that we identify with biological evolution ultimately emerged from a kind of proto-evolution, supported by a kind of protolife, that ultimately must trace back to the spontaneous emergence of the first molecular systems capable of some sort of evolutionary dynamic. Earlier it was shown that even a molecular system as simple as an autogen can give rise to a form of natural selection. the emergence of this constellation of properties enabling evolution … marks a fundamental shift in the dynamical organization of the natural world, a shift from thermodynamic and morphodynamic processes to teleodynamic processes.’ (430) The key to understanding the entire line of development from the Big Bang to your capacity to interpret this review lies in understanding the key transitional moments where qualitatively new energetic powers emerge.
Deacon applies the same methodological approach to explaining consciousness and agency as he does to explaining morphogenesis. He searches for the mediating term between unconscious morphodynamic systems and conscious life-forms. He zeroes in on sentience. Human beings design all sorts of sensing technologies (like thermostats), but sentience or feeling it is not only functional, it is intentional. The thermostat regulates the temperature in the room, but is not in the least intentional: it functions, but does not act for the sake of maintaining an environment that it requires to continue functioning. But sentience is the product of organic systems that evolved and as such have survival value. The higher level capacities of living things are the products of natural selection shaping, sculpting, and honing organic matter over billions of years. The crucial transitions are from self-replicating molecules to self-maintaining simple single cell organisms, from self-maintaining single cell-organisms to sentient life forms aware of their environment and able to work to maintain a life-supporting system state, and then from sentient life-forms to social self-conscious agents capable of building a human, social, symbolic world out of the givenness of natural materials.
With the emergence of sentience the universe crosses the threshold between being a meaningless thermodynamic system running itself down over time to a world of value and meaning. Value for Deacon is, at root, life-supporting material conditions. Sentient life forms feel their environment and therefore suffer (sense life-threatening changes) as well as, on the other side, experience joy– increase in their vital powers, as Spinoza would say. The important point is that Deacon shows how values are fully compatible with a complex materialist ontology (as I also tried to show, but in a much less scientifically rigorous way, in Materialist Ethics and Life-Value). The symbolic, meaningful human world has been created not simply through the manifestation of survival instincts in social life survival but the conscious shaping of the social world to serve and satisfy certain norms.
Human beings do not simply act for the sake of given ends, we are agents, capable of deliberately constructing the ends that we serve. The material of human norms is symbolic, not physical, but the emergence of the capacity for symbolic thought and the creative activity that it directs can be explained, if Deacon is correct, in a way that preserves the causal uniformity of nature. Human freedom is thus not, as Descartes argued, a function of the operation of non-physical, non-mechanical causality, but a function of the power of human beings to understand and intervene causally in the world. The secret to human freedom is that it is ententional, not spiritual or divine: it results from action in relation to an imagined end state not yet physically present. “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 world with respect to some conserved core dynamical constraints. This is not a breakdown of causal efficacy; in fact, just the opposite. Being an agent mans being a locus of causal efficacy.”(480)
With human agency the argument comes full circle. Deacon began from a picture of the universe as an energetic system governed by the second law of thermodynamics. Without introducing exotic causalities or question-begging ideal substances or divine intelligences, he has provided a coherent explanation of how life can emerge from non-life and consciousness from unconscious elements. I am sure that the experts in the various fields that Deacon’s rich and complex account draws upon would be able to raise problems that I am incapable of even seeing, but sometimes science must advance not by parts but by wholesale re-framings. As philosophy is always involved in wholesale re-framings (mechanism, after all, was as much a global philosophical world-view as it was empirical science), philosophers have to be a part of these conversations, even if they might not understand all the scientific details. Deacon is aware of the philosophical dimensions of his account and draws on philosophy where he finds conceptual problems with older frames and as he tries to explain and justify his novel approach. This is not a book for a lazy Sunday afternoon in summer read; it requires full attention and even then, non-scientists will be hard pressed to follow in some spots. But these arguments concern our being here, with the distinctive powers that we have. Who can fail to be fascinated by the answer that Deacon sketches?