Piero Scaruffi

Ecological Realism: The embodied mind (These are excerpts from, or extensions to, the material published in my book "The Nature of Consciousness") The Information Flow The brain is in the body, and the body is in the world. No living being can live in a vacuum. Life in a vacuum is an oxymoron. Life needs an environment. Life is transformation, and, without an environment, physical laws forbid transformation. Transformation requires energy from an external source. Life is a continuously changing equilibrium between an organism and its environment. Even the most remote organism is connected to the rest of the biosphere via the air, which is the way it is mainly because of the metabolism of living beings (the atmosphere contains far more methane and other gases than chemical reactions alone would create). From a biological perspective, the mind is one of the many organs that help an organism survive in the real world. Ultimately, from a biological perspective, the mind belongs to a body. Passive cognition In the 1960s the work of USA biologist James-Jerome Gibson originated "ecological realism", the view that meaning is located in the interaction between living beings and the environment. Gibson started out with a critique of the traditional model of perception that harked back to Helmholtz, and ended with a new view of what cognition is. The 19th-century German physicist Hermann von Helmholtz thought that perceptions are "unconscious inferences". Mind is isolated from the world and only knows what the senses deliver. The senses deliver signals, and the mind has to figure out how to interpret them. The mind uses whatever knowledge it has accrued. As proven by optical illusions, mind makes assumptions on such signals and "infers" what reality is. Perceptions are "hypotheses" on what reality just might be. But all of this inferring is largely invisible. Most of what goes on in the brain does not surface to the mind. According to Gibson, instead, the process of perceiving is a process of "picking up" information that is available in the environment. The "information" that the organism uses originates from the interaction between the organism and its environment. Gibson believes that the sensory data coming from the environment already contain all the relationships needed to navigate the environment. No "representation" is needed by the brain. The brain’s sole task is to "pick up" the information that the environment provides with each sensory experience. The way this information is acquired is rather passive: the organism is free to move in the world, but it is the environment that feeds it information. The way this information is "processed" is direct: there is no mediation by the mind. Action follows perception, and the two can be viewed as dual aspects of the same process. Cognitive life is passive as in "no active effort to understand information". The brain does not organize the sensory input or process the sense data. The brain is simply a tool to seek and extract information about the environment. What the brain truly does is recognize information. Information, for Gibson, is patterns: any pattern of environmental stimuli that repeats itself over time constitutes "information". Our brain is an organ capable of discovering "invariants" in the environmental stimuli. Physically, that pattern of stimuli is a pattern of energy that impinges on the brain. A pattern of energy that flows through the sensory system, and that depends in a reliable way on the structure of the environment, is information. In other words, any pattern of energy that corresponds to the structure of the world carries information about the world. We use this principle, for example, every time we draw a line to represent the edge of an object. Perception is a continuously ongoing process and consists in detecting the invariants of the environment. The function of the brain is to orient the organs of perception for seeking and extracting information from the continuous energy flow of the environment. Thus perception and action are not separate processes. And perception cannot be separated from the environment in which the perceptive system (the organism) evolved and from the information which is present in that environment. Perception, action and the environment are tightly related. Far from being simply a background for action, the environment is therefore viewed as a source of stimulation. Organisms move in the world using all the information that is available in it. Perceptual organs are not passive: they can orient themselves to pick up information, to "resonate" with the information in the environment. Ultimately, there is much more information in the world and less in the head than was traditionally assumed. And the environment does most of the work that we traditionally ascribe to the mind. David Marr explained "how" we see. Gibson explained "what" we see, and why we see what we see. Directed cognition The USA psychologist Ulric Neisser refined this thesis. He defined cognition as the skill of dealing with knowledge that comes from the environment. The mind developed to cope with that knowledge. Neisser agrees with Gibson that organisms "pick up" information from the environment, but he differs from Gibson in that he argues in favor of directionality of exploration by the organism: the organism is not completely passive in the hands of the environment, but somehow it has a cognitive apparatus that directs its search for information. Neisser wondered how the brain recognizes an object. Comparing a visual experience with all known objects is just too time-consuming. But comparing a visual experience with all known objects "that make sense" in that situation is much more feasible. Using a variant of Edward Tolman’s cognitive maps, Neisser concluded that the brain probably "knows" in advance which objects are more likely to be "seen" in a certain situation. Some "anticipatory schemas" narrow down the set of objects that one "expects" to find in that certain situation. If I enter a restaurant, I will not expect to see a couch, but I will expect to see tables and chairs. This makes it much easier for my brain to recognize a table for a table. Schemas account for how the organism can gather the available information from the environment. Between perception and action there exists a direct relation, one that is expressed by schemas. A schema is a blueprint for what information the organism presumes to encounter and what that information entails in the environment. The organism selects information from the environment based on its anticipatory schemas. "We can see only what we know how to look for". At every instant the organism constructs anticipations of information that make it easy to pick it up when it becomes available. Once picked up, information may in turn result in a change of the original schema, to direct further exploration of the environment. Perception is therefore a perennial cycle, from schemas to action (schemas direct action) to information (action picks up information) to schemas (information modifies schemas). The schema accounts for adaptive behavior while conserving the preeminence of cognitive processes. Neisser’s "cyclical" theory of perception also explains how the mind "filters" the huge amount of information that would exceed its capacity. An orienting schema of the nearby environment, or "cognitive map", guides the organism around the environment. A cognitive map contains schemas of the objects in the environment and spatial relations between the objects. Perception is not about classifying objects in categories, creating concepts or any other sophisticated cognitive process. Perception is about using the information available in the surroundings for the purpose of directing action in it. Perception and cognition transform the perceiver: an organism "is" the cognitive acts in which it engages. Organisms and environment The USA philosopher Fred Dretske also believes that information is in the environment and cognitive agents simply absorb it, thereby creating mental states. As Dretske puts it, information is what we can learn about the environment from a sensory signal. From a biological standpoint, Daniel Dennett's "intentional stance" defines just the relationship between an organism and its environment. The organism continuously reflects its environment, as the organization of its system implicitly contains a representation of the environment. The organism refers to the environment. Intentionality defines an organism as a function of its beliefs and desires, which are products of natural selection. Intentional states are not internal states of the system, but descriptions of the relationship between the system and its environment. The British psychologist Henry Plotkin defines knowledge itself as incorporating the environment. His focus is on the harmony established over the centuries between the organization and structure of a living being and the world it inhabits. Adaptation is the act of incorporating the outside world into the organism's structure and organization. More properly, this is "biological" knowledge. But human knowledge is simply a subset of biological knowledge. This school of thought has been influential in reversing the traditional role between the living organism and the environment: the organism is no longer a protagonist, its free will unleashed and its creativity unlimited. The organism is a far more passive actor in the overall drama of Nature, one that has to rely upon (and whose behavior is conditioned by) the information that the environment supplies. Ecological realism has also been influential in reshaping the profile of a cognitive system: since a cognitive system is simply an apparatus to pick up information and translate it into appropriate action, it turns out that pretty much any living thing can be considered, to some extent, as a cognitive system. Life and cognition have lost some of their exclusive appeal, as we realized how constrained and passive they are. Situation Theory This conceptual revolution was, ultimately, about the meaning of life, and therefore affects Semantics. The USA mathematicians John Barwise and John Perry devised a "situational semantics" which reverses Frege's theory of meaning. According to the tradition founded at the end of the 19th century by the German mathematician and philosopher Gottlob Frege, meaning is located in the world of sense. On the contrary, Barwise and Perry anchor their theory of meaning to a biological fact: the world is full of meaning that living organisms can use. Meaning is not an exclusive of language: it is pervasive in nature (e.g., smoke means fire). Meaning involves the informational content of situations and arises from regularities in the world. Reality is made of situations. Meaning arises out of recurring relations between situations. Barwise's unit of reasoning are situations because reality comes in situations. Situations are made of objects and spatio-temporal locations; objects have properties and stand in relations. A living organism (a part of the world capable of perception and action) must be able to cope with the ever new situations during its course of events and to anticipate the future course of events. It must be able to pick up information about one situation from another situation. This can be realized by identifying similarities between situations, and relations between such similarities. Each organism performs this process of breaking down reality in a different way, as each organism "sees" reality in a different way, based on its ecological needs. The type of a situation is determined by the regularities that the situation exhibits. Regularities are acquired by adaptation to the environment and define the behavior of an organism in the environment. The similarities between various situations make it possible for an organism to make sense of the world. At the same time they are understood by all members of the same species, by a whole "linguistic community". Formally, one situation can contain information about another situation only if there is a relation that holds between situations sharing similarities with the former situation and situations sharing similarities with the latter situation. In that case the first situation "means" the second. Meaning is defined as relations that allow one situation to contain information about another situation. Barwise emphasizes the "relational" nature of perception (e.g., perception is a relation between perceiver and perceived) and the "circumstantial" nature of information (information is information about the world). The mind, which processes that information, is strictly controlled by the environment. Goal-driven Evolution In his "teleo-evolutionary" theory, the Romanian philosopher Radu Bogdan summarized things this way: organisms are systems that are genetically programmed to maintain and replicate themselves, therefore they must guide themselves to their goals, therefore they need to obtain relevant information about their environment, therefore they need to be cognitive. It makes evolutionary sense that cognition should appear. But what "guides" the organism, and its cognition, is the environment. It could not be anything else. Cognitive systems are guided by the environment in their goal-driven behavior. Cognitive systems are actually the very product of the evolutionary pressure of that guiding behavior. Central to his thinking is the concept of "goal-directedness": natural selection presupposes goal-directedness. Goal-directedness arises from the genes themselves, which operate "goal-directedly". Organisms manage to survive and multiply in a hostile world by organizing themselves to achieve specific, limited goals in an ecological niche. To pursue their goals, organisms evolve ways to identify and track those goals. Such ways determine which knowledge is necessary. To obtain such knowledge, organisms learn to exploit pervasive and recurrent patterns of information in the world. The information tasks necessary to manipulate such information "select" the appropriate type of cognitive faculties that the organism must be capable of. Imagine an organism that cannot recognize recurring situations: in every single moment of its life, it must improvise how to deal with the current situation. An organism that can recognize recurring situations can develop ways to best react to those types of situations. These "ways" make up its cognition. The organisms that survived are those whose cognition matched the situations that recur in their ecological niche. The mind is not only controlled by the environment: it was created (or at least "selected") by the environment. Cognition as Adaptation The USA psychologist Randy Gallistel believes that the nature of cognition lies in some "organizational" principles. Those are principles on how to organize a system so that the system can adjust rapidly and efficiently. In other words, "something" enables living organisms to make rapid adjustments of patterns of action in response to the environment. That "something" is the way they are internally organized. No movement in nature is random. It always serves the purpose of "adapting" the state of the system to the external conditions. No matter how intelligent the action of a living being appears to be, that action satisfies the same general principle: adaptation. At first sight, human action looks too complex to be reduced to such a simple scenario. Nevertheless, Gallistel believes that human behavior can be decomposed down to more and more elementary units, and those units do satisfy the general principle of action for the sake of adaptation only. The point is to explain how an action that looks like a whole can be decomposed in many coordinated lower-level actions. In Gallistel’s hypothesis, the elementary units of behavior (reflex, oscillator, servomechanism, i.e. external stimulus to internal signal to muscle contraction) are "catalyzed" by units at the higher levels of the system. Drawing from the model of a central program advanced by the USA philosopher Paul Weiss, Gallistel assumes that units are organized in a hierarchy that allows for competition and antagonism. A central program is a unit of behavior that is activated as a whole. A central program "selectively potentiates" subsets of lower-level units according to their relevance to the current goal. The principles that determine the "selective potentiation" of lower-level units are the same that govern the properties of elementary units. Each unit in the hierarchy appears to act independently, but it is held together in a consistent whole. Situated cognition The USA computer scientist Rodney Brooks, the originator of "situated cognition", shifted the emphasis of Artificial Intelligence to the interaction between an agent and its environment. Brooks’ "situated" agents have no knowledge. Their memory is not a locus of representation but simply the place where behavior is generated. In Brooks' "subsumption" architecture, behavior is determined by the structure of the environment. The cognitive system has no need to represent the world, but only for how to operate in the world. There is no centralized function that coordinates the entire cognitive system, but a number of distributed decisional centers that operate in parallel, each of them performing a different task. The system does not have the explicit representation of what it is doing. It does have parallel processes that represent only their very limited goals. The system decomposes in layers of goal-driven behavior, each layer being a network of finite-state automata, and incrementally composes its behavior through the interaction with the world. Brooks can therefore account for the very fast response times required in the real world. In the real world there is no clear-cut difference between perception, reasoning and action. Brooks turns the mind into one of many agents that live in the environment. The environment is the center of action, not the mind. The environment is action, continuous action, continuously changing. Only a system of separate, autonomous control systems could possibly react and adapt to such a context. The world contains all the information that the organism needs. Therefore there is no need to represent it in the mind. The environment acts like a memory external to the organism, from which the organism can retrieve any kind of information through perception. "Intelligent" behavior can be partitioned into a set of asynchronous tasks (eating, walking, etc.), each endowed with a mechanism of perception and action. An artificial organism can be built incrementally by gradually adding new tasks. Behavior arises from layers of competence. Cognition is rational kinematics. Brooks’ ultimate point is that every intelligent being has a body! Vehicles The Italian neurophysiologist Valentino Breitenberg proposed a thought experiment which consists in mentally building progressively more complex machines, starting with the most elementary ones. At the beginning, there are only "vehicles" that respond to their environment. The first vehicle is simply made of a motor and a sensor: the speed of the motor is controlled by the sensor, motion is meant to be only forward. But in the real world this vehicle is subject to friction (where friction is the "metaphysical" sum of all forces of the environment) and therefore the trajectory will tend to deviate from the straight line. In fact, in a pond the movement would be quite complex. That's the whole point: despite the simple internal workings of these machines, they seem to be alive. We can increase little by little their circuitry, and at each step these vehicles seem to acquire not only new skills, but also a stronger personality. The second vehicle is still fairly simple: two motors and two sensors. The sensor is designed to get excited by whatever kind of matter. It turns out that depending on the way they are wired, these vehicles react differently to the exciting matter: one runs towards it, the other one runs away from it. One is "aggressive", one is "afraid". And so forth. As their circuitry increases, the vehicles seem to exhibit more sophisticated feelings. By adding simple electro-mechanical components, Breitenberg induces the machines to reason logically (via McCulloch-Pitts neurons). As the devices get more complicated, shapes are recognized; regularities are represented; properties of objects are discriminated. Hebbian associations (that get stronger as they are used) allow for concepts to emerge. Soon the machines start exhibiting learning and memory. Causation (as constant succession) and attention (as self-control over associations) finally lead to trains of thoughts. At this point something very similar to the human mind can be said to be born, and all Breitenberg has to do is add circuitry for social and moral skills. The leitmotiv of Breitenberg's research is that it is far easier to create machines that exhibit "cognitive" behavior simply by interacting with the environment than it is to analyze their behavior and try to deduce the internal structure that produces such cognitive behavior. Breitenberg's ideas spawned an entire generation of robots, which their constructors appropriately tend to call "creatures". Robots do not evolve The British philosopher Andy Clark, too, wants to bring back the body into the reasoning brain. We can dispose of the body and still find ways that a brain would calculate how to perform actions, but the very reason that we have bodies is that bodies make it a lot easier to perform those actions even without calculating every single movement. The fact that a body's movements are constrained by the body's structure is actually an advantage: once the brain directs a general action, there are only so many ways that the action can be carried out by the body. There is no need to calculate ways that are beyond the capabilities of the body. Clark attacks the kind of Artificial Intelligence that wants to equip machines with logic and "problem solving" techniques (usually based on an abstract representation of the world.) This is a way to build a brain without taking into account the body; a very intelligent brain (possibly more intelligent than its creators) but pathetically out of touch with the reality of its body and its possible interactions with the environment. Clark, instead, envisions a road to artificial intelligence via "autonomous agents", who are controllers of bodily action along the lines of Rodney Brooks' "subsumption architectures". They have simpler "brains", but their behavior is largely driven by their interaction with the environment instead of pure logic. Where logical systems take input from perception and calculate action, these agents use action as perception. Thus the distinction between perception and action fades away, as they are two sides of the same coin. And cognition becomes simply the interaction with the environment, not a system of logic. Learning occurs while we act. This, Clark reminds us, is more similar to the "quick and dirty" strategies employed by Nature. All these theories of "situated agents" that criticize the "problem-solving" approach (the approach in which there is a "brain" planning everything the body does) tend to miss an important point. They look at biological organisms for inspiration, but they forget that biological organisms evolve. Robots do not evolve (yet). That is the very basic reason that Artificial Intelligence scientists came up with the need for a problem solver, for an entity capable of solving every possible problem on purely logical bases. Biological organisms embody their interaction with the environment: their body has been sculpted by evolution to optimize that interaction. It is hard to create a robot that can display the same degree of "fitness". What we do not have (yet) is evolving robots: robots that, given an environment, will build better and better fit robots. It is just very difficult to have a robot build another robot. At best, we have software inside a robot that evolves and fine-tunes itself. But that is not what happens in nature, where it is the hardware itself (not just the software) that evolves. The reason that Artificial Intelligence originally adopted the view of a "disembodied brain" is that a robot "is" disembodied: it is just a container for a mind. Our bodies are not mere containers of minds: our bodies have been shaped by evolution to be the natural object and subject of the mind. When Clark and Brooks build their robots, they commit the same sin of the "problem-solving" crowd: they design the robot, instead of letting evolution design it. The problem-solving crowd builds a system that uses logic to decide behavior. Clark and Brooks use their own logic (the logic of their brains) to design a robot that (according to their logical thinking) will behave correctly in its environment. They have simply moved the problem-solving activity from the brain of the machine to the brain of the humans that design it. But nothing substantial has changed. Autopoiesis From a different perspective, similar conceptual changes were advanced in the 1960s by the Chilean neurobiologist Humberto Maturana when he argued that the relationship with the environment molds the configuration of a cognitive system. "Autopoiesis" is the process by which living systems form and maintain their boundaries in the face of an ever-changing environment. It is the process by which an organism can continuously reorganize its own structure to interact with the world while remaining itself. Adaptation consists in regenerating the organism's structure so that its relationship to the environment remains constant. Autopoiesis is a pattern of organization common to all living systems. Living systems are organized in closed loops. A living system is a network in which the function of each component is to create or transform other components while maintaining the circular organization of the whole. A cell exhibits autopoiesis, as does the Earth as a whole. The product of a living system is a new organization of itself. It continually produces itself. The being and the doing are the same. Autopoiesis is self-maintenance. Organisms use energy (mainly from light) and matter (water, carbon, nitrogen, etc) to continuously remake themselves. Living systems are units of interaction. They only exist in an environment. They cannot be understood independently of their environment. They exhibit "exergonic" metabolism, which provides energy for the "endergonic" synthesis of polymers, i.e. for growth and replication. In fact, the organism reorganizes based on environmental stimuli. The stimulus, therefore, can be viewed as that part of the environment that is absorbed by the structure. The circular organization of living organisms constitutes a homeostatic system whose function is to maintain this very same circular organization. It is such circular organization that makes a living system a unit of interaction. At the same time, it is this circular organization that helps maintain the organism's identity through its interactions with the environment. Due to this circular organization, a living system is a self-referential system. At the same time, a living system operates as an inductive system and in a predictive manner: its organization reflects regularities in the environment. Living systems are organized according to the principle: "what happened once will happen again". Cognition is biological in the sense that the cognitive domain of an organism is defined by its interactions with the environment. Cognition is the way in which an autopoietic system interacts with the environment (ie, reorganizes itself). It is the result of the structural coupling with the environment which causes the continuous reorganization. All living systems are cognitive systems. Cognition is simply the process of maintaining oneself by acting in the environment. Action and cognition cannot be separated: "all doing is knowing and all knowing is doing". Living is a process of cognition. In summary, an autopoietic system is a network of transformation and destruction processes whose components interact to continuously regenerate the network. An autopoietic system holds constant its organization (its identity). Autopoiesis generates a structural coupling with the environment: the structure of the nervous system of an organism generates patterns of activity that are triggered by perturbations from the environment and that contribute to the continuing autopoiesis of the organism. Autopoiesis is necessary and sufficient to characterize a living system. A living organism is defined by the fact that its organization makes it continually self-producing (autopoietic), i.e. not only autonomous but also self-referential ("the being and doing of an autopoietic system are inseparable"). Autopoiesis progressively generates more and more complex organisms and then intelligent organisms. Multi-cellular organisms are born when two or more autopoietic units engage in an interaction that takes place more often than any of the interactions of each unit with the rest of the environment (a "structural coupling"). Inert elements then become macromolecules, and macromolecules become organic cells, and so on towards cellular organisms and intelligent beings. A nervous system enables the living organism to expand the set of possible internal states and to expand the possible ways of structural coupling. But the nervous system is self-referential: perception is not representation of external world. Perception does not represent, it specifies the external world. No living system exists independent of cognition. Each cognitive act is not about knowing the environment, but about reorganizing oneself in accordance with the environment. The autopoietic system knows only itself. There is no representation of the external world. There is just reorganization of the system based on the external world. Intelligent behavior originates in extremely simple processes: the living cell is nothing special, but many living cells one next to the other become a complex system thanks to autopoiesis. Even life's origin can be easily explained: at some point in its history the Earth presented conditions that made the formation of autopoietic systems almost inevitable. The whole process of life depends not on the components of a living organism, but on its organization. Autopoiesis is about organization, not about the nature of the components. Evolution is a natural drift, a consequence of the conservation of autopoiesis and adaptation. There is no need for an external guiding force to direct evolution. All is needed is conservation of identity and capacity for reproduction. For Maturana, information is a pointless concept. Communication is not transmission of information but rather coordination of behavior among living systems. Maturana extends the term "linguistic" to any mutually generated domain of interactions (any "consensual domain"). When two or more living organisms interact recurrently, they generate a social coupling. Language emerges from such social coupling. In this view, language is "connotative" and not "denotative". Its function is to orient the organism within its cognitive domain. The point Maturana reiterates is that cognition is a purely biological phenomenon. Organisms do not use any representational structures: their intelligent behavior is due only to the continuous change in their nervous system as induced by perception. Intelligence is action. Memory is not an abstract entity but simply the ability to recreate the behavior that best couples with a recurring situation within the environment. Gaia and the noosphere The biosphere as a whole is autopoietic as it maintains itself through a careful balance of elements. Life (the sum of all living beings) can counter cosmological forces and make sure that the Earth continues to be a feasible habitat for life. Living beings use the chemicals available in the air and on the surface of the Earth and produce other chemicals that are released in the air and on the surface of the Earth. They do so at the rate that keeps the air and the surface of the Earth in balance with whatever cosmological forces operate on the Earth. To paraphrase the USA biologist Lynn Margulis, life "is" the surface of the Earth. It is not surprising that the Russian geologist Vladimir Vernadsky in 1926 ranked living matter as the most powerful of geological forces (he even described how life opposes gravity's vertical pull by growing, running, swimming and even flying). It is not surprising that the British biologist James Lovelock views the entire surface of the Earth, including "inanimate" matter, as a living being (which he named "Gaia"). Vernadsky even thought that the Earth is developing its own mind, the "noosphere", the aggregation of the cognitive activity of all its living matter. Enaction Following Maurice Merleau-Ponty's philosophical thought and drawing inspiration from Buddhist meditative practice, the Chilean philosopher Francisco Varela, a close associate of Maturana, argued in favor of an "enactive" approach to cognition: cognition as embodied action (or "enaction"), evolution not as optimal adaptation but as "natural drift". His stance views the human body both as matter and as experience, both as a biological entity and a phenomenological entity. Varela believes in the emergent formation of direct experience without the need to posit the existence of a self. The mind is selfless. "Self" refers to a set of mental and bodily formations that are linked by causal coherence over time. At the same time the world is not a given, but reflects the actions in which we engage, i.e. it is "enacted" from our actions (or structural coupling). Everything that exists is the projection of a brain. Organisms do not adapt to a pre-given world. Organisms and environment mutually specify each other. Organisms drift naturally in the environment. Environmental regularities arise from the interaction between a living organism and its environment. The world of an organism is "enacted" by the history of its structural coupling with the environment. Perception is perceptually guided action (or sensorimotor enactment). Cognitive structures emerge from the recurrent sensorimotor activity that enables such a process. And perceptually guided action is constrained by the need to preserve the integrity of the organism (ontogeny) and its lineage (phylogeny). Varela assigns an almost metaphysical meaning to Maturana’s biological findings. Life is an elegant dance between the organism and the environment. The mind is the tune of that dance. The mind is the body The USA philosopher Mark Johnson rejects the theory (that he calls "objectivism") that meaning is an abstract relation between symbolic representation and objective reality, and that reason transcends the body. Johnson, instead, believes that "imagination" is essential for human cognition, and imagination, in turn, arises from the human body. Imagination is taken to be both the creative quality (in the "Platonic" tradition) and the faculty that connects perception with reason (in the "Aristotelian" tradition). The human body is not just a machine that passively receives perceptions. It is an entity involved in a complex interaction with the world and with other bodies. Human rationality is "embodied" because our reality is shaped by bodily movements Johnson points out that, like all animals, we are bodies connected to the world. Whatever else we are, it comes from this basic fact, therefore from our bodily essence, from our "embodiment". Our mental life is a creation of this embodiment. It is only in the embodiment that one can find the meaning of our mental life. His building blocks are Immanuel Kant's "schemas" (non-propositional structures of imagination), which are then amplified into concepts by metaphorical projection, and these concepts then structure and constrain our understanding and reasoning. Johnson claims that, ultimately, the body "is" the mind. The Extended Phenotype A powerful metaphor to express the dependence of an organism on its environment, and the fact that the organism does not make sense without its environment, has been introduced by the British biologist Richard Dawkins: the "extended phenotype" includes the world an organism interacts with. The organism alone (the "phenotype") does not have biological relevance. What makes sense is an open system made of the organism and its neighbors. For example, a cobweb is still part of the spider. The control of an organism is never complete inside and null outside: there is rather a continuum of degrees of control, which allows partiality of control inside (e.g., parasites operate on the nervous system of their hosts) and an extension of control outside (as in the cobweb). To some extent the very genome of a cell can be viewed as a representation of the environment inside the cell. The USA philosopher Ruth Millikan went further claiming that, when determining the function of a biological "system", the "system" must include more than just the organism, something that extends beyond its skin. Furthermore, the system often needs the cooperation of other systems: the immune system can only operate if it is attacked by viruses. An organism is only a part of a larger biological system. Tools (whether cobwebs or buckets or cars) are an extension of the organism which serve a specific purpose. Buckets store water. Cars help us move faster. Computers are an extension of the organism that serve the purpose of simulating a person or even an entire world. No matter how simple or how complex, those tools are an extension of our organism. The model of the extended phenotype is consistent with a theory advanced by the USA biologist Richard Lewontin. Each organism is the subject of continuous development throughout its life. And such development is driven by mutually interacting genes and environment. Genes per se cannot determine the phenotype, abilities or tendencies. The organism is both the subject and the object of evolution. Organisms construct environments that are the conditions for their own further evolution and for the evolutions of nature itself towards new environments. Organism and environment mutually specify each other. The Universe is a Message To Life The picture painted by these biologists is completely opposite to the one painted by the logicians who worked on formalizing Logic: where the logician’s program is based on the assumption that reason is an abstract manipulation of symbols, the biologist’s program is based on the assumption that reason is bodily experience grounded in the environment. The two views could not be farther apart. Implicit in the logician’s project were the assumptions that meaning is based on truth and reference, that the mind is independent of the body, that reasoning is independent of the mind (logic exists in a world of its own, regardless of whether somebody uses it or not), and all minds use the same reasoning system. The biological approach puts the mind back firmly in the body, the body in the environment and meaning in the relationship between them. The reasoning system we use depends on our collective experience as a species and on our individual experience as bodies. We are left to face the vast influence that the environment has on the development and evolution of the mental faculties of an organism, no less so than of its body. The development of an organism, an ecosystem, or any other living entity, is due to interaction with the environment. In a different world, the same genomes would generate different beings. The universe is a message to life and to mind. Further Reading Barwise John & Perry John: SITUATIONS AND ATTITUDES (MIT Press, 1983) Bogdan Radu: GROUNDS FOR COGNITION (Lawrence Erlbaum, 1994) Breitenberg Valentino: VEHICLES (MIT Press, 1984) Brooks Rodney & Luc Steels: THE ARTIFICIAL LIFE ROUTE TO ARTIFICIAL INTELLIGENCE (Lawrence Erlbaum, 1995) Clancey William: SITUATED COGNITION (Cambridge Univ Press, 1997) Clark Andy: BEING THERE (MIT Press, 1997) Dawkins Richard: THE EXTENDED PHENOTYPE (OUP, 1982) Dennett Daniel: THE INTENTIONAL STANCE (MIT Press, 1987) Dretske Fred: KNOWLEDGE AND THE FLOW OF INFORMATION (MIT Press, 1981) Dretske Fred: EXPLAINING BEHAVIOR (MIT Press, 1988) Gallistel C.R.: THE ORGANIZATION OF ACTION (Erlbaum, 1980) Gibson James Jerome: THE SENSES CONSIDERED AS PERCEPTUAL SYSTEMS (Houghton Mifflin, 1966) Gibson James Jerome: THE ECOLOGICAL APPROACH TO VISUAL PERCEPTION (Houghton Mifflin, 1979) Helmholtz Hermann: TREATISE ON PHYSIOLOGICAL OPTICS (1866) Johnson Mark: THE BODY IN THE MIND (Univ of Chicago Press, 1987) Kitchener Robert: PIAGET'S THEORY OF KNOWLEDGE (Yale University Press, 1986) Lewontin Richard: HUMAN DIVERSITY (W.H.Freeman, 1981) Lovelock James: GAIA (Oxford University Press, 1979) Maturana Humberto: AUTOPOIESIS AND COGNITION (Reidel, 1980) Maturana Humberto & Varela Francisco: THE TREE OF KNOWLEDGE (Shambhala, 1992) Millikan Ruth: LANGUAGE, THOUGHT AND OTHER BIOLOGICAL CATEGORIES (MIT Press, 1987) Millikan Ruth: WHAT IS BEHAVIOR? (MIT Press, 1991) Neisser Ulric: COGNITION AND REALITY (Freeman, 1975) Neisser Ulric: THE REMEMBERING SELF (Cambridge University Press, 1994) Neisser Ulric: THE PERCEIVED SELF (Cambridge Univ Press, 1994) Plotkin Henry: DARWIN MACHINES AND THE NATURE OF KNOWLEDGE (Harvard University Press, 1994) Varela Francisco, Thompson Evan & Rosch Eleanor: THE EMBODIED MIND (MIT Press, 1991) Varela Francisco: PRINCIPLES OF BIOLOGICAL AUTONOMY (North Holland, 1979) Vernadsky Vladimir: THE BIOSPHERE (?, 1926)(Synergetics, 1986) Winograd Terry & Flores Fernando: UNDERSTANDING COMPUTERS AND COGNITION (Ablex, 1986)