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Biology of Mind

Part 2: Looking deep into the past

by Dee Wilson

(Part two of three)

July 19, 2021


Part 2 of "The Biology of Mind" continues the review of three books on the evolution of mind: Merlin Sheldrake's, Entangled Life, Antonio Damasio's, The Strange Order of Things and  Peter Godfrey-Smith's, Metazoa.   Part 2  begins with a discussion of symbiotic relationships between plants and fungi, and proceeds to an evolutionary account of the appearance of subjectivity and 'sentience' in animals several hundred million years ago, based on Damasio's and Godfrey-Smith's books.  


When I began writing  this article, I intended to divide my discussion into two parts: (1) indicators of "incipient mind" in bacteria, fungi and multi- cellular organisms before the appearance of animals;  and (2)  the development of animal minds, including  discussion of subjectivity and consciousness.  However, I found there was too much complex subject matter regarding the development of subjectivity in animals to finish this article in two parts. I plan to write a third and final discussion of the mental abilities of animals and consciousness when I find the courage, or foolhardiness, to jump into the briar patch of discussions of this subject  


If anyone has found good sources of information, or theory, regarding the evolution of mind, please let me know.         

An order to emergence

Part one of this article discussed the evolution of mind beginning with single cell bacteria about 3.8 billion years ago through the development of multi-cellular fungi, 1-2 billion years ago. Part one also discussed the development of symbiotic relationships between and among bacteria and fungi. Part two begins with a discussion of symbiotic relationships between fungi and green algae, “the ancestors of all land plants” (Sheldrake, p. 123) taken from the chapter, “Before Roots,” in Entangled Life.

In his chapter, “From Single Cells to Nervous Systems and Minds,” (in The Strange Order of Things), Damasio asserts that “There is an order to the emergence of things,” ( p.68). Damasio states that “Historically, the world of bacteria – cells without nuclei – known as prokaryotes – was followed, about 2 billion years later, by the far more complicated world of nucleated cells, or eukaryotes. Multi- cellular organisms, or metazoans, came next, 700 to 600 million years ago.”  (p. 54) This story of evolutionary history leaves out the development of fungi 1-2 billion years ago (or possibly) longer, and the symbiotic relationships between and among fungi and plants that preceded the appearance of nervous systems and/or brains in animals.

Sheldrake provides the following account of the developing relationships between fungi and algae that preceded the appearance of nervous systems in animals:

“Sometime around six hundred million years ago, green algae began to move out of shallow fresh waters and onto land. … The evolution of plants transformed the planet and its atmosphere and was one of the pivotal transitions in the history of life … Before plants, land was scorched and desolate. … Crusts of photosynthetic bacteria, extremophile algae, and fungi were able to make a living in open air. But the harsh conditions meant that life on earth was overwhelmingly an aquatic event.” (pp. 123-24) 

According to Sheldrake, “the algae ancestors of plants had no roots, no way to store or transport water and no experience in extracting nutrients from solid ground. … It was only by striking up new relationships with fungi that algae were able to make it on to land. These early alliances evolved into what we now call “mycorrhizal relationships.” Today, more than ninety percent of plant species depend on mycorrhizal fungi. They are the rule, not the exception … plants and mycorrhizal fungi exact a collective flourishing that underpins our past, present and future.” (p. 124)

Plants and fungi engage “in a more promiscuous type of symbiosis in which a single plant can be coupled to many fungi at once, and a single fungus can be coupled to many plants. … By growing within plant roots, mycorrhizal fungi acquire privileged access to these (sugars and lipids) sources of energy. They get fed. However, photosynthesis isn’t enough to support life. Plants and fungi need more than a source of energy. Water and minerals must be scavenged from the ground. … Fungi can forage in a way that plants can’t. By hosting fungi within their roots, plants gain hugely improved access to these sources of nutrients. They, too, get fed.” (p. 126) 

Sheldrake asserts that “by the time the first roots evolved, the mycorrhizal association ( i.e., between algae and fungi) were already some fifty million years old. Mycorrhizal fungi are the roots of all subsequent life on land. … Mycorrhizal fungi are so prolific that their mycelium makes up between a third and half of the living mass of soils.” (p. 127) 

The relationship of plants and mycorrhizal fungi resembles an economic exchange: “Plant shoots engage with light and air, while the fungi and plant roots engage with the solid ground. Plants pack up light and carbon dioxide into lipids and sugars. Mycorrhizal fungi unpack nutrients bound up in rocks and decomposing material.” (p. 130) Mycorrhizal fungi “mine phosphorous from the soil and transfer it to their plant partners. If plants are fertilized with phosphorous, they grow more.” Mycorrhizal fungi are also able to burrow into solid rock, giving early plant life access to minerals such as calcium and silica.  “Mycorrhizal fungi can provide up to eighty percent of a plant’s nitrogen and as much as a hundred percent of its phosphorous,” as well as “other crucial nutrients such as zinc and copper. In return, plants allocate up to thirty percent of the carbon they harvest to their mycorrhizal partners.” (p. 132)

The relationships between plants and mycorrhizal fungi resemble complex social relationships among animals and humans. Sheldrake states that “Plants actions are informed by what is happening in the sensory world of their fungal partners. Similarly, fungal behaviors are informed by what is happening in the sensory world of their plant partners. Using information from between fifteen and twenty  different senses, a plant’s shoots and leaves explore the air and adjust their behavior based on continuous subtle changes in their surroundings. … a mycorrhizal fungus must sniff-out sources of nutrients, proliferate within them, mingle with crowds of other microbes – absorb the nutrients and divert them around its rambling network of a body. Information must be integrated across an immense number of hyphal tips, which at any one moment can be strung out between several different plants and sprawl over tens of meters.”  (p.135)    


Researchers have begun to study how plants and mycorrhizal fungi maintain “a balance of power.” (p. 135) According to Sheldrake, Toby Kiers, a researcher at the University of Amsterdam, has found that plants and mycorrhizal fungi “strike compromises, resolve trade- offs, and employ sophisticated trading strategies.” In one experiment, Kiers found that “plant roots were able to supply carbon preferentially to fungal strains that provided them with more phosphorous. In return, fungi that received more carbon from the plant supplied it with more phosphorous. Exchange was in some sense negotiated between the two depending on the availability of resources.” (p. 136)      

The relationship between plant and fungal  partners involves an ongoing mutual adaptation and negotiation that is not strictly determined by genetics, it appears. “Their behavior is flexible, a set of ongoing negotiations that depend on what is taking place around them and in other parts of themselves. … it’s clear that at any one moment plants and fungi face a number of options. And options entail choices, however these choices turn out to be made.” (p. 136) Kiers opines that “There’s a set of options, and somehow information has to be integrated and one of the options has to be chosen.” (p. 136)

Kiers has studied the influence of what might be termed supply and demand on fungal networks.  Sheldrake states: “In parts of a mycelial network where phosphorous was scarce, the plant paid a higher “price,” supplying more carbon the fungus for every unit it received. Where phosphorous was more readily available, the fungus received a less favorable “exchange rate.” In addition, “the fungus coordinated its trading behavior across the network… The fungus actively transported phosphorous – from areas of abundance, where it fetched a low price when exchanged with a plant root, to areas of scarcity where it was in higher demand and fetched a higher price.”  (p. 137)

Sheldrake acknowledges that “there are situations in which plant and fungal exchanges don’t seem to obey what we would recognize as rational trading strategies.” (p. 139) However, it’s a big stretch from this admission to concluding that Kiers and like-minded researchers have engaged in an implausible projection of economic principles onto fungal/ plant relationships, skepticism based on little more than an assumption that plants and mycorrhizal fungi cannot be intelligent and strategic in how they manage their mysterious relationships.  If other researchers have a more plausible way of describing plant/fungal relationships and exchanges, they should offer it absent sarcasm and ridicule. 

Sheldrake states: “Neither plants nor fungi inherit each other. They inherit a tendency to associate, but they conduct what are, by the standards of many ancient symbioses, open relationships. As in the earliest days of life on land, plants form their relationships depending on who’s around. The same goes for fungi;” and “the ability to reform their relationships, or evolve entirely new ones, can allow partners to respond to changing circumstances.”(p. 140) In other words, the partnerships of plants and mycorrhizal fungi are not strictly determined by genetics; they depend on circumstances and opportunities, and vary greatly from species to species. This is  (in my view) mind at work in multi-cellular organisms that lack nervous systems.

Sheldrake references the suggestion of anthropologists Natasha Myers and Carla Hustak that “the concept on involution better captures the entangled pushing and pulling of organisms constantly inventing new ways to live with and alongside one another.” “It was their tendency to involve themselves in the lives of others that enabled plants to borrow a root system for fifty million years while they evolved one of their own. … all plants still depend on mycorrhizal fungi to manage their underground lives. Their involuntary tendencies enabled fungi to borrow a photosynthesizing alga to handle their atmospheric affairs. They still do. … by associating with one another, all participants wander outside and beyond prior limits.”(p. 142) It appears that even in multicellular fungi and plants without nervous systems, homeostasis does more than manage relationships between and among organisms; it also leads to exploration of potential social relationships with different types of living things.

Sheldrake uses the language of agency to describe mycorrhizal fungi /plant relationships:  these organisms “manage their complex affairs,”; “adjust their behavior based on continuous subtle changes in their surroundings;”(p. 135); “strike compromises, resolve tradeoffs and employ sophisticated trading strategies;” (p. 136) “adapt to new conditions.” (p. 142) How far the agency of mycorrhizal fungi extends in Sheldrake’s description is an open question.  Sheldrake discusses models of changes in the atmosphere following the partnerships developed between mycorrhizal fungi and plant: “The amount of carbon dioxide and oxygen, in the atmosphere, and global temperatures – all varied according to the efficiency of mycorrhizal exchange… mycorrhizal fungi would have made a substantial contribution to the dramatic drawdown of carbon dioxide in the Devonian period.” (p. 132) Sheldrake quotes Katie Field, a professor at the University of Leeds: “Our results suggest that mycorrhizal relationships have played a role in the evolution of much of life on earth.” ( p. 132) He comments that “Mycorrhizal relationships are as old as plants and have been shaping Earth’s future for hundreds of millions of years.” (p. 144) It’s unclear to me whether Sheldrake is suggesting that mycorrhizal fungi have engaged in the engineering of atmospheric changes, or is using the language of agency, i.e., “shaping Earth’s future” metaphorically.  It’s one thing to acknowledge the extraordinary intelligence and improvisational capacities of mycorrhizal fungi in seeking out and sustaining partnerships with plants; it’s another thing entirely to suggest that mycorrhizal fungi have exercised God like powers on the earth’s evolution.

Nervous systems

In The Strange Order of Things (chapter 4), Damasio asserts that nervous systems in multicellular organisms appeared about 540-600 million years ago in the Precambrian period. Damasio reminds readers that “Life, even multicellular life, managed quite well without nervous systems for about 3 billion years. We should reflect on this time before we decide when perception, intelligence, sociality and emotions made their first appearance on the world stage.” (p. 56)

In Damasio’s account, “Nervous systems emerged as servants to the rest of the organisms – to bodies, more precisely, not the other way around.” ( p. 56) Nervous systems depend on cells, i.e., neurons, that are excitable, “a glorification of bioelectrical signaling first accomplished modestly in simple celled organisms such as bacteria,”  according to Damasio. Neurons give rise to nervous fibers, axons, that “terminate at almost every nook and cranny of the body.” (p.57)  Nervous fibers “often travel long distances away from the centrally located parent cell body,” while in evolved nervous systems, “a reciprocal set of nervous fibers travels in the opposite direction, from myriad body parts to the central components of the nervous system,” the purpose of which is “Surveillance over the state of life … a massive snooping and reporting job whose goal is to let the brain know what is going on elsewhere in the body so that it can intervene when needed and appropriate. … Eventually, the surveillance job yields conscious feelings and enters the subjective mind. ( pp. 57-58)            


According to Damasio, the massive surveillance of the state of  organisms made possible by nervous systems serves the goal of homeostasis in two ways: 1) by providing information on the state of the body and 2) by anticipating and predicting future states. “The brain executes homeostatic compensations on behalf of the whole organism.” (p. 59)

In a passage that reflects a theme in Sheldrake’s, Entangled Life, Damasio comments that “the beginning of nerve systems was not this complicated … It literally consisted of nerve nets, a reticulum, or network of wires … In those simple nervous systems, there is not a sharp distinction between “central” and “peripheral” components. They consist of a wiring of neurons that crisscross the body.” (p. 59) And “nerve nets accomplish very basic perception. The nets also do visceral regulation …” ( p. 60) However, ... they have limited memory and “They lack mapping ability,” the capacity which Damasio believes underlies the capacity for consciousness and feeling. He writes, “in my perspective, … consciousness and feeling depend on the existence of minds, … so that brains would be capable of fine multisensory perceptions based on the mapping of numerous component features.” (p. 61)

For Damasio, mind depends on the capacity to generate “internal representations” of both external and internal events which allows an organism to figure out the shape of objects, guide the movement of limbs or the entire body with precision and become aware of feelings that reflect the state of the organism at a point in time.  Image-guided movements “were advantageous even if an organism were not conscious of  the images formed within it. The organism would not yet be capable of subjectivity and would be unable to inspect the images in its own mind, but still the images could automatically guide the execution of a movement.” ( p. 62)

Damasio provides what he describes as “a suitable historical perspective:” (p. 64)

  1. The emergence of nervous systems several hundred million years ago “has been a servant of whole organism homeostasis,” i.e., in which the well-being of the whole organism takes precedence over the well-being of any of its constituent parts.

  2. Nervous systems interact with the bodies of which they are a part in an entirely different way from the interactions nervous systems have with the surrounding environment.

  3. Nervous systems opened the way for social interactions “that transcended homeostatic needs and gained considerable autonomy.” (p. 65)

  4. “Complex functions of the higher nervous system have their functional roots in simpler operations of the lower devices of the system itself …”  (p. 65) The capacity for feeling and consciousness is not grounded in the capacities of the cerebral cortex but in “the operation of the brain stem nuclei and of the peripheral nervous systems. “ (p. 65) 

To paraphrase Damasio’s account of the emergence of mind more concretely: nervous systems emerged to regulate the life processes  (both internal and external) of complex multicellular organisms and, in doing so, applied the homeostatic imperative present in each cell’s functioning to the entire multi-cellular organism. The capacity for feelings is a way of expressing and regulating the well-being of the whole organism; and was created long before the higher-level mental operations of the cerebral cortex. Consciousness arose out of feelings that could be represented internally “based on its ongoing sensory descriptions of both internal and external events.” Feelings were created by nervous systems in multicellular organisms that moved from cooperative relationships among cells and colonies of cells to “whole body” identity.  (pp. 64-65) “There is an overall life of the organism, a global life … resulting from the high-dimension integration of the contributing lives within it,” ( p. 67) Damasio asserts. Nervous systems create the capacity for complex multi- cellular organisms to act as a unified system rather than a federation of cooperative cells.   

Damasio returns repeatedly to the theme of nervous systems “as assistants to the body,” and “coordinators of the life process in bodies complex and diversified enough that the functional articulation of tissues, organs and systems  as well as their relationship to the environment required a dedicated system to achieve the coordination.” (p. 66) He maintains that “Minds depend on the presence of nervous systems charged with helping run life efficiently, in their respective bodies, and on a host of interactions of nervous systems and bodies. “No body, never mind.” (p. 66) 


Internal representations of minds

In Damasio’s view, the evolution of minds capable of feeling and consciousness requires more than sensing and responding, the capacity to learn and adapt, strategize, cooperate with other organisms and choose among options. Single celled organisms have these capacities which I have termed “incipient mind.” Damasio reserves the term ‘mind’ to refer to the capacity for internal representations of both the external and internal worlds as reflected in mapping and images, a capacity which Damasio wrongly believes originated in animals with nervous systems. Fungi able to find their way out of a maze must, it seems, be able to represent the world around them in some way, i.e., engage in mapping spatial relationships.

However, putting aside the question of when the capacity for internal, i.e., mental, representations appeared in evolutionary history, Damasio’s argument is that the earliest organisms could sense and immediately respond to stimuli, but could not configure a world with complex spatial relationships and distinct features that he refers to as “images.” Animals with “nervous systems had become capable of sensing different parts of the environment – physical objects, other living creatures, and responding with appropriate movements …( p. 74) And then, “long after nervous systems were able to respond to many features of the objects and movements that they sensed, both outside and inside their own organism, there began the ability to map the objects and events being sensed … nervous systems literally began drawing maps of the configurations of objects and events in space …”  (p. 74) In other words, sensory input became more finely delineated and was transformed into a world with complex relationships among constituent parts represented by “images.” Damasio’s insistence on referring to representations created by touch, smell, sound and even feelings as images, a visual term, leads to confusion. He writes: “Now stretch your imagination and think of maps built from touch or smell or taste … and think of maps built from the “objects” and “events” that occur within the organism  … the maps … are none other than the contents of what we experience as images in our minds. The maps of each sensory modality are the basis for the integration that make images possible and those images …  are the constituents of minds. They are a transformative step in the existence of complex living organisms … (p. 75) The clarity of this paragraph leaves much to be desired (to put it mildly), but the broad outlines of Damasio’s argument are clearly drawn: mind appears in evolutionary history when nervous systems become able to utilize sensory input to create internal representations, i.e., images of what is perceived or felt through mapping the relationship between their constituent parts. Minds create sensory and affective worlds through these internal representations. If Damasio had the dramatic flair of a great filmmaker, at this point he might invoke the memorable chords of “Thus Spoke Zarathustra,” as in 2001: A Space Odyssey.


However, Damasio’s account of the evolution from sensation to internal representations, i.e., images, is deficient in important respects. In Damasio’s view, “images of the outside world originate in sensory probes,” (p. 79). And “Each sensory probe is devoted to sampling and describing specific aspects of the outside world … None of the five senses alone produces a comprehensive description of the outside world, although our brains eventually integrate the partial contributions of each sense into an overall description … The result of this integration approximates a “whole” object description …” (p. 79) This discussion does not do justice to the extent that the mental representations of animals are the result of highly differentiated sensory probes and the strength and balance of their various senses.  Animals that depend primarily on sound, touch or smell to represent the world, and which may lack one or more of these senses, cannot experience the same sensory world as humans. Bats, bees, other insects and dogs have different sensory worlds. Possibly, Damasio conflates mental representations with “images” because humans are visually oriented to an extreme degree compared to many other species. Strictly speaking, nervous systems do not represent a sensory world, but rather create quite different sensory worlds constructed by the availability, strength and combination of various sensory probes. 

Damasio maintains that “the images of the internal world are the ones that we describe with such terms as “well-being,” “fatigue” or “malaise,”… they are of a special kind because we do not “picture” the old interior world in quite the same way we picture objects out in the world. There is less detail  … These images of the old internal world are none other than the core components of feelings.” Furthermore, the old internal world is a world of fluctuating life regulation ... and “must reflect the goodness or badness of the state of that interior universe. Everything in this old internal world is qualified, good, bad or in between. This is a world of valence.” (pp. 82-83) In Damasio’s account, feelings reflect the state of the organism at a point in time while “images” created by sensory data represent the external world. But what if feelings that reflect internal states effect in myriad ways the mental representations created by the senses? The boundary between feelings, sensations and mental representations of the sensory world are porous, i.e., interactive, in ways Damasio does not discuss in this chapter. Daniel Kahneman’s book, Thinking Fast and Slow (2011) discusses this subject at length.     

Damasio asserts that the capacity of various sensory probes to locate images, and to make the rudimentary distinction between external and internal “is necessary for the construction of an overall organism image … which is a critical step in the generation of subjectivity.” (p. 83)

The Minds of Animals

In Metazoa: Animal Life and The Birth of The Mind, Godfrey-Smith states that “Animals are made up of many cells living as a unit; beyond that, they live in a huge variety of ways. They include corals as well as giraffes, wasps that are smaller than some single cells as well as whales at fifty tons. … In biology, now, the word “animal” refers to any organism found on a particular branch of the genealogical tree, regardless of how it lives or what it looks like. A coral is a much an animal as a wolf is.” (p. 36) Godfrey-Smith describes an evolutional history of animals that begins with organisms that lack nervous systems such as sponges and placozoans, which are either motionless in their adult form (sponges) or which crawl “nervously and microscopically,”  (placozoans) or comb jellies which have nervous systems and swim using cilia, tiny hairs that beat in rhythm. (p. 41) These animals appeared early in the evolution of animals;  According to Godfrey- Smith, “they are simple animals in various ways. They have few parts and not many kinds of cells. … they are genetically very far from us.” (p. 41) Godfrey-Smith follows the evolution of what he terms “sentience” in animals which appears to mean something similar to what Damasio calls feelings. He comments: “We need to continually avoid falling into the habit of thinking that all forms of experience must be human-like in various ways. When the word “consciousness” is used for the very broad idea of felt experience, it is easy to go astray. … in some ways, “sentience” is a good term for the broader concept.” (p. 18)

Godfrey-Smith asserts that “sentience” is often used for particular kinds of experience – for pleasure and pain and related experiences that include a valuation, good or bad. … But these may not be only kinds of basic or simple experiences.” (p. 18) He suggests that “sentience” may also include sensory experiences that “may be distinct from evaluating what is good or bad,” (p. 19) an idea with which Damasio concurs, even though in Damasio’s account of the evolution of mind these two types of “sentience” appear in tandem.

Godfrey- Smith introduces the concept of subjectivity which is a bridge between sentience and consciousness. He states: “in some ways, this book is about the evolution of subjectivity – what subjectivity is and how it came to be. Subjects are the home of experience, where experience lives. (p. 19) In a later chapter, Godfrey-Smith refers to subjectivity as “a matter of seeming, of for- me-ness” whereas “Agency is a matter of doing, trying, initiating. Agency is by-me-ness; it is being a source of action  and its effects.” (p. 59) He asserts that “As everyday concepts, subjectivity and agency gesture toward different aspects of a person or animal, a more sensory side and a more active side. From an evolutionary point of view, they are tied closely together. Sensing has its … (purpose) in the control of action. Nothing is gained biologically from taking in information that is not put to use. The evolution of mind includes the coupled evolution of agency and subjectivity.” (p. 59) 

Action and movement

Godfrey-Smith has been greatly influenced by the thinking of Fred Keijzer, a Dutch psychologist and philosopher. Keijzer emphasizes “the shaping of action” as a central concern in the early evolution of nervous systems.” (p. 59) Keijzer suggests that the shaping of complex actions results in new kinds of animal sensing, especially touch, may register that “something external has happened,” i.e., bodily movement began to create a clearer distinction between the inner and outer world, a feature of subjectivity. Godfrey-Smith asserts that “the evolution of animals produced multicellular action achieved through sheets of cells that contract, twist, and grasp. Nerves and muscle make this possible; a sponge can do nothing like it. Action of this kind was a transformative invention in evolution; it changed everything.” (pp. 60-61)

An evolutionary path

Godfrey-Smith traces an evolutionary path from early animals such as “Dickinsonia,” a flat organism without limbs or complex senses such as eyes which lived on the seafloor more than 600 million years ago during the Ediacaran era in a low oxygen world. In the later Edicaran world, the Avalon assemblage appeared which probably included sponges. According to Godrey-Smith, “The Avalon organisms seem to have lived in quite deep seas, too dark for photosynthesis, hundreds and perhaps thousands of meters down.” (p. 65)  “These creatures might have lived on tiny-dissolved particles of organic carbon – their branching - upon- branching design has a “fractal” organization that maximizes surface area, allowing a steady uptake of this fine organic mist, along with oxygen to burn it.” (p. 66)

Next came the White Sea assembly around 560 million years ago that contained fossils with more diverse body parts which suggests the likelihood of movement. They lived on shallow seafloors in “microbial  mats” that were in some sense alive.” (p. 66) These surfaces included bacteria, algae like organisms and small animals, some of which could move. This evolutionary era included a fossil called Helminthoid-ichnites which appears to have engaged in scavenging, i.e., “of an animal consuming the dead. It is also the first physical trace of targeted motion, movement aimed at a goal which is sensed.” (p. 67) 

According to Godfrey- Smith, “The evidence is good that nervous systems evolved in a body with something like a radial design,  … called the bilaterian, or bilaterally symmetrical body … bodies with a left-right axis, as well as a top and bottom. Our bodies are bilaterian bodies, along with those of ants, snail and seahorses.”   (pp. 70-71) This is important because “the bilaterian body with its left- right symmetry was an innovation especially in the realm of action. The bilaterian body is set up to go somewhere. There are no non- bilaterian bodies on dry land.”  (p. 72) In Godfrey-Smith’s account,  the nervous systems of early bilaterian animals such as flatworms evolved to facilitate increased capacity for physical action. Improved sensory capacities increased the capacities of animal bodies to move effectively with purpose.

Initially, improved sensory capacities in animals led to a more clearly delineated sensory world. Banded shrimp were the first animals mentioned by Godfrey-Smith “that can see an object like you, the first ones with eyes that can distinguish objects … This is also the first animal that can move fast ... This is an animal with a different relationship to its surroundings, a different mode of being …”  (p.79) Animals of this kind evolved during the Cambrian era about 540 million years ago. Godfrey Smith asserts that “Among its fossils are animals with hard parts, legs and shells, and conspicuous eyes.” (p. 79) He states: “An evolutionary pathway becomes visible, one that begins with moving slowly toward food, and then not so slowly … From there scavenging morphs into predation. … Once animals are trying to eat you, tracking your scent and following, it pays to improve one’s own senses and means of motion. The evolution of eyes may have had a special role in this process …” (p. 80)

In this evolutionary story, the appearance of scavenging and then predation led to “an arms race.”  (p. 80) In the Cambrian Godfrey-Smith asserts, “Arthropods appear to have led the way. This group today includes vast numbers of insects,” (p. 80) though insects were late arrivals among this group of animals. Godfrey-Smith maintains that “Arthropods at this time seem to have invented a new way of being an animal, with a skeleton that scaffolds and organizes complex actions. They also invented claws and to go with them, image forming eyes.” (p. 80)   

Regarding this critical period in the evolution of mind, Damasio’s and Godfrey-Smith’s accounts have similarities and differences.  Damasio comments:

“The existence of images was not possible before nervous systems grew in complexity. The world of sponges and cnidarians such as hydras was enriched by the gift of a simple nervous system, but image making was unlikely to have been among its capabilities. We can only guess but minds that resemble ours in some elementary way  belong to far more elaborate creatures whose nervous systems and behaviors had developed great complexity. In all likelihood, they are present in insects  … and probably in most or all vertebrates. Birds clearly have minds …” (p. 79) For Damasio, the capacity for sensory images which he refers to as “mapmaking” was accompanied by the development of feelings in “the old internal world… of fluctuating life regulation”(p. 83)  and in the “newer internal world … dominated by our bony skeleton and by the muscles attached to it.”  (p. 81) Images of the  sensory world were from their origin enmeshed in affect that tracks internal homeostasis.  In Damasio’s view, both the old and new internal world of animals has valence, i.e., is experienced as “good, bad, or in between.” (p. 83)

Godfrey-Smith agrees that animals fundamentally changed “when they evolved multi-cellular sensing, encouraging parts of their bodies to become maps or reflections of fragments of their surroundings.”  (p. 86) However, Godfrey-Smith is not convinced that sensory improvements and capacity for “sentience” developed in tandem. Rather, he is impressed by the way in which animals were enabled by images and mapmaking to track “the divide between self and other, between the animal itself and everything else.” He states that “This kind of sensing that marks the relation between self and other is an important feature of animal life. It gives rise to a new way of being in the world. It involves the establishment of a point of view, a perspective, in a new sense.” (p. 87)

It is possible that both Damasio and Godfrey-Smith have pointed out different dimensions of mind in animals created by complex nervous systems and the capacity for images and mapmaking: (1) an internal world of feelings that registered both parts of the world and experiences as good, bad or indifferent for (2) creatures who were able to distinguish between self and others. In both Damasio’s and Godfrey-Smith’s accounts of evolutionary history, these mental capacities appeared several hundred million years ago, rather than recently through the development of the cerebral cortex. 

Subjectivity in Animals

Godfrey-Smith reminds reader that by the Cambrian era, “evolution has brought forth … not just some new organisms, larger and more complicated than earlier ones, but a new kind of being, a new kind of self … Central to animal evolution was the invention of new kinds of action, the coordinated motion of millions of cells made possible by muscle and nervous systems. … we encounter beings that respond to the environment as a realm beyond, sensing and acting on the basis of a tacit sense of self …(p. 104) Some of these animals are capable of subjectivity and agency. He asserts that “Subjectivity involves feelings and seemings;  agency is doing and initiating. All living things (or all living things composed of cells) exhibit something like subjectivity and agency, but these features take a different form in the animal case. … “Animal agency brings with it the origin of subjects.” (pp. 104- 105)

At this point, Godrey- Smith’s account of the evolution of mind moves into the murky conceptual depths occupied by philosophers, neuroscientists and a few marine biologists. The most valuable parts of this discussion are the concrete elements:

  • Some marine biologists have “collected considerable evidence that these animals (i.e., hermit crabs, a type of crustacean) can feel something like pain.” (p. 89)

  • Nociception, i.e.,  the detection of damage, “is very common in animals, but it often lends itself to interpretation as something like a reflex. … biologists tend to regard nociception as not sufficient for pain, and they look for markers of something more, something that seems tied to  feeling of pain. All these markers … are controversial to some extent. They include tending and protecting wounds, seeking out pain killing chemicals (the same drugs that work in us ...) … and some kinds of learning from the good and bad consequences of actions. Some biologists have shown a kind of wound tending in shrimp, for example.” (p. 90) 

  • Some animals (such as hermit crabs) make trade-offs between painful experiences “and the various other benefits and costs that apply to that situation,” which suggests “that for a crab, there is a range of events and possibilities that are seen as good or bad, and the pain of a small shock, though bad, is factored into decision along with other considerations.” (p. 90) This is a big departure from the idea that most animals are robots operating solely on the basis of stimulus and response. What hermit crabs do, according to some biologists, is more like a rational decision-making process than an automatic reaction determined by genes.

Godrey-Smith comments that “This work on crustaceans was, as far as I know, the first on any invertebrate animal that produced reasonably good evidence for pain.” (p. 91) He goes on to say: “In crabs and shrimp we have animals recognizable, even conspicuous in their marks of experience. They act at our pace and scale; and have our sort of agenda.” He notices that “Crustaceans are in the same large group of arthropods as insects … I have tended to think of insects as unfeeling robots, as most do. But there is a gestalt shift you can undergo by way of their relatives, the amiable crustaceans. The crustaceans put insects into a new light. Do insects experience their lives also? (p. 91)  

Godfrey- Smith proceeds carefully in his evolutionary account of mind in animals. He has the scholarly virtue of clarity regarding sources; and gives credit (by name) to the researchers and philosophers who have influenced his thinking. However, his account of the indicators of mind in early animals does not explain why the capacity for feelings was associated with the development of nervous systems. Godfrey-Smith is still uncertain on this point as he attempts to remain credible with biologists and neuroscientists who remain skeptical regarding indicators of feelings in non-vertebrates. He also makes a cardinal error in separating the capacity of some early animals to perceive a more finely delineated sensory world from the capacity for affect. Damasio does not make this mistake because he has a theoretical framework that links what he terms “images” in the sensory world to “images” in the experience of affect. Damasio also understands that animal minds that have strong similarities to the human mind are grounded in affect. Animal cognition and human cognition are immersed in a sea of feelings. Damasio understands this because of his insight that the capacity for feelings grows out of homeostasis, i.e., “life favorable or life unfavorable” states of the body of early life forms, including single celled bacteria.

Why is affect the foundation of animal minds?  

Damasio’s account of the evolution of mind suggests (but does not explicitly state) the following: the capacity for affect is the basis, the sine qua non, for the unitary awareness of animals with nervous systems. There were animals that lacked nervous systems or had simple versions of nervous systems in the pre-Cambrian and early Cambrian era more than 500 million years ago. “These animals depended on networks of cells for information about the external world and to achieve internal homeostasis.“  Damasio asserts that “the processes that supported feelings after minds emerged had been in place long before and included the mechanisms necessary to generate  the hallmark component of feelings-valence ( i.e., feelings are good or bad).” ( p. 124) The animals who appeared early in evolutionary history were large collections of cells which gradually took on specialized functions. These animals might be described as colonies of cells, or federations of cells with symbiotic relationships, a quasi-unity perhaps.


 According to Damasio, “the nervous system gradually assumes the role of master coordinator for all the other global systems while it also manages the relationships between the organism and its surrounding environment.” (p. 122) Nervous systems accomplish what homeostatic mechanisms that had existed for billions of years were unable to do in complex animals with hundreds of thousands or millions of cells with specialized functions: act on behalf of the whole organism rather than its independent parts. This is necessary for the organism “which is the integrated whole of all those living cells, tissues, organs and systems” and “can only survive if the homeostatic limits are closely observed.” (p. 50)

Damasio states: “There is an overall life of the organism, a global life, as it were resulting from the high-dimension integration of the contributing lives within it. Organism life transcends the lives of its cells …” (p. 67) Feelings in animals embody (literally) the experience of the whole organism.  We refer to “gut feelings”, or “heartache” or to experiences that are “hard to swallow,” or “bitter” and which “leave a bad taste in the mouth.”  Damasio explains, “First, using images made from the oldest components of the organism’s interior – nature gradually fashioned feelings.” (p. 77) This old interior world “must reflect the goodness or badness of the state of that interior universe,” (pp. 82-83) in my view to reflect the experience of a unitary organism. 

 There is also a newer internal world “dominated by our bony skeleton and by the muscles attached to it the skeletal muscles.” (p. 80)  The new internal world locates the organism in relation to the external world, which according to Damasio, “is necessary for the construction of an overall organism image, … a critical step in the generation of subjectivity.” (p. 83) To rephrase Damasio’s account: the old interior world of affect embodies the experience of a unitary organism struggling to regulate its life processes, while the new internal world of feeling locates the body of the organism in reference to the world surrounding it. 

As a rule, humans take the unity of themselves and animals for granted, though there is some cultural variation in this regard. In his history of the Vikings, Children of Ash and Elm, Neil Price comments that “At the most fundamental level of all, inside every Viking-Age person was not just some abstract ’soul’ … but several separate and independent beings.” The Vikings viewed the individual person as a multiplicity of beings, which sounds bizarre in our civilization. We are amused by a dog which bites its tail, view multiple personalities as a type of pathology and are distressed by trauma victims who engage in self-mutilation.  It is the fragmentation of experience that surprises us, not unitary awareness which does not seem to require a scientific explanation. However, one of the most surprising characteristics of animals with complex nervous systems is the capacity to experience themselves as a unity, a capacity required for effective action and for agency, i.e., the ability to initiate goal directed activity absent a stimulus in the immediate environment. Godfrey-Smith is fascinated with octopus’ which have several brains and sensory arms; yet are still able to act as a unitary organism. How is this possible?  Damasio’s answer might be: “because they have feelings.”


 A better understanding of the biology of mind requires that we think carefully about aspects of our experience usually taken for granted. An early achievement of evolution was to produce a unitary awareness in animals consisting of hundreds of thousands or millions of cells, which was achieved through the integration of affect (with valence) and sensory information, i.e., and then to create multiple ways of integrating sensory information with bodily experiences. Damasio asserts: “The ground zero of being corresponds to a deceptively continuous and endless feeling state,” which “always refers to the body of the organism in which they emerge. Feelings portray the organism’s interior – the state of internal organs and of internal operations.” (p. 102) And “the reference to the organism is dominated by one sector of the body: the old interior world of the viscera that are located in the abdomen, thorax and thick of the skin …” (p. 103) which together provide “a moment- to-moment report on the state of life in the interior of the organism.” (p. 104)  “Feelings are not mere “information” in the strict computational sense,” (Damasio asserts) because they always have valence “which “judges” the current efficiency of bodily states.” (p. 106)

According to this perspective, the idea that the complex mental abilities of animals and humans can be understood by reference to computer operations is completely mistaken. The minds of animals are grounded in feelings which Damasio asserts “are, through and through … phenomena of both bodies and nervous systems.” In Damasio’s view, “feeling is not a perception of the body state in the conventional sense of the term. Here the duality of subject- object, of perceiver-perceived breaks down. … there is unity instead. Feeling is the mental aspect of that unity.” (p. 126)  A plausible hypothesis is that central nervous systems can exercise control of organisms because all cells, organs and other elements of mind and body participate in the positive affect resulting from the regulation of internal processes and capacity for effective action, affect much more powerful than the well-regulated state of individual cells and systems of cells. It is likely that the unitary awareness of animals has an affective payoff both connected to and independent of food sources and self-protection.  


Damasio notices the importance of the gastrointestinal tract and the enteric nervous system in the regulation of feeling and mood in humans. The enteric nervous system consists of 100 – 600 million neurons; it is often referred to as “the second brain.” Remarkably, “the function of the enteric nervous system is largely under its own control. The central nervous system does not tell the enteric nervous system what to do or how to do it … but there is a continuous cross talk between the enteric nervous system and the central nervous system.” (p. 134) Damasio comments that “digestive disorders tend to correlate with pathologies of mood, and curiously the enteric nervous system produces 95% of the body’s serotonin, a transmitter notable for its key role in in disorders of affect and their correction.” (p. 134) The gastrointestinal tract is home to billions of bacteria, “more individual organisms than there are there are individual human cells in one entire organism. How they influence the world of feeling … is an intriguing topic for twenty-first century science,” Damasio states. (p. 136) In Damasio’s account, feelings depend on the integration of two nervous systems, one associated with the old interior world of the gastrointestinal tract and the centralized nervous system developed for command and control of a unitary organism.


Implications for human experience

If Damasio’s view that ‘mind’ in animals is grounded in affect is correct (and I believe it is), it is remarkable that many philosophers, neuroscientists and biologists continue to debate whether animals have feelings, or which animals have feelings. Damasio is a theorist, and like all theorists, he is as interested in the coherence of his theory and its inter-relationships as in evidence for each specific element of his theory. Nevertheless, Damasio is thoroughly familiar with the relevant science which he interprets differently than most other experts on the biology of mind.

The strength of useful theories is that they illuminate the causes of a wide range of phenomena previously assumed to be unrelated. The idea that the cognition of animals, including the human animal, is grounded in affect with valence, and is a necessary condition for their unitary awareness, sheds light on the following features of human experience:  

  • Feelings have a powerful influence on cognition and on decision making, especially quick intuitive judgments based on a thin amount of information as discussed in Daniel Kahneman’s great book on cognitive psychology, Thinking Fast and Slow (2011). It is possible to control the influence of emotional reactions on decision making, but only by slowing down and engaging in careful deliberation before making decisions. Impulsive reactions to events are likely to have a strong emotional component.  

  • Humans perceive the physical world and social interactions through the prism of affect, a habit of mind which makes objectivity hard to achieve. Sensory input and feelings about that input are not on separate tracks, so to speak. Rather emotions and feelings influence the selection of sensory information and bodily sensations to attend to; and contribute to how even small amounts of information are interpreted through stories that often have imaginative elements.  (Kahneman, 2011)

  • The most common defense mechanisms, i.e.,  denial and projection, have deep affective roots. Humans protect their beliefs by denying the validity of evidence  (including sensory input) that challenges them. They also frequently project their own motives onto others with whom they are in conflict without being aware that they are doing so.    

  • The human brain and body do not process information “bits;” rather body and brain working together give sensory information and social experience an emotional and affective context. Affect, sensory input and imagination combine to give meaning to experience.            

  • Under extreme stress, or when subjected to the combination of terror and powerlessness in traumatic experiences, the integrated system that guides fight/flight reactions is shattered and mind (often including memory) and body are fragmented as the capacity to integrate experience and engage in resistance is compromised.  Judith Herman’s inspired book, Trauma and Recovery (1992), provides a detailed analysis of the shattering effect of trauma on the mind and body of victims. Traumatic experiences can fragment consciousness and memory in strange ways, while the boundaries of self-awareness can be dissolved or relinquished in ecstasy or mystical experiences. As a rule, the capacity for affect supports  a person’s unitary awareness, but it can do otherwise in extreme situations.     

  • Meditation and mindfulness are effective ways of calming down and regulating emotional states because they tap into homeostatic processes created by “a deceptively continuous and endless feeling state,” (p. 100) an underlying sense of well-being created at the cellular level by both body and brain working together. Arguably, the capacity for affect is created by genes through the combination of homeostatic messages from every cell and every system of cells.    

  •  Body awareness is a means of accessing this deep source of well-being potentially present in every human being, and (by hypothesis) in animals as well. It is unnecessary to accept this assertion on faith; or engage in pointless debates regarding psychology or religion. Every person can discover this inner source of well-being regardless of religious beliefs or their absence; or fail to discover it after a good faith effort. Possibly,  the deep world of affect that sustains homeostasis is the primary source of experiences of the sacred.

  • All human experience has valence, i.e., is felt to be good, bad or somewhere in between. Experience is never just information; all sensory experiences have a feeling component.  For this reason, it is rare to hear anyone describe their experiences, however prosaic, in purely neutral terms. Human experience is value laden through and through.       


Part 3 of this article will continue the discussion of subjectivity in animals and jump into the quagmire of the discussion of  consciousness.

One major theme has emerged from the discussion of early life forms such as fungi and animals with nervous systems: the mental ability of organisms - both simple and complex - depends on their capacity to combine and integrate large numbers of cells with increasingly specialized functions, and to create a unity of purpose in multi-celled organisms through unitary awareness. Animals that can feel the state of their whole organism can utilize these abilities to motivate and guide effective action, in part through the integration of multiple sensory modalities, and because their motivation is not conflicted.  These animals are aware of the difference between themselves and other organisms like them, and the difference between the internal and external world.

The requirements of integrating mind and body, including the integration of several internal systems and sensory modalities, and of resolving both intrapsychic and interpersonal conflicts, will be a major theme of the discussion of subjectivity and consciousness in the third and final part of this article.      


Read Part One

Read Part Three

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