Here is a translation I commissioned by José Villavicencio of Joaquin Fuster’s “Prólogo” to F. Hayek El Orden Sensorial. Unión Editorial, S.A., Madrid, pp 11-23, 2004.
Salzburg, May 17, 1976
Dear Professor Fuster,
Thank you very much for your kind letter dated the 3rd of this month and that I have in my possession without having had the time to answer because I needed to make a visit to Vienna. It is always a great pleasure when, for long periods of time, I learn that someone is interested or remembers my Sensory Order. I have not seen any specific reaction to my way of thinking, even though it is a fact that it was recently republished for a second time indicating then that there is someone reading it…
In order to understand the intellectual roots of The Sensory Order, I am inviting the reader to visit Vienna, the Vienna of the last century’s 2nd decade, where and when the author wrote this work’s first draft. There is the beginning of the prestigious positivist school of philosophy, whose epistemology Hayek adopted in order to clarify the philosophical base of the mind. For positivist psychologists of the period, the mind is accessed through the senses, and thus, that’s what he begins to do, using empiricism, as it was the usage in vogue by the great physiologist-psychologist of the XIX century (e.g., Mach, Helmholtz, Wundt, James Müller). Just beyond the entrance to the senses is perception, the cognitive faculty that represents the world that surrounds us in the form of objects, animate and inanimate beings, and structures and physical occurrences, all with their respective dimensions of time and space. Perception, for the empiricists and the young Hayek, is the preferred way of the mind. According to them, if we understood the physiology of how we understand the world around us, we would understand the structure and the functions of the mind in the brain. The theoretical psychologists of the moment, and thus Hayek in the beginning build their theories of perception starting from basic elements of sensation, what Mach (1885) calls “the pure nucleus of sensation”. From here on, in apposition to primary sensations, the primary structures of perception begin to be formed, and these, in apposition too, form the more elaborate structure of the mind. The mental panorama of perception becomes a type of mirror or group of mirrors that reflect the exterior world. Thus, the mental world reflects the exterior world as a mosaic perception of itself. From this comes the so-called psychology of “mosaic”. It is a vision somewhat static of things that do not take into account the huge informative power of perceiving that resides in the almost limitless combination of the aforementioned basic elements of elemental sensation. Hayek quickly abandoned this static and restrictive vision of perception for a more dynamic vision of that function and more in line with the principles of interaction between perception and memory, fundamental with the principle—previously espoused by Helmholtz—that stipulated that perception sprouts from memory, and vice-versa, memory from perception. We not only remember that we perceive, but we perceive because we remember. Even more, for both, memory and perception, the “rule” is a rule of relations. Objects from both define themselves by a relation of spatial and temporal associations between elements of lesser rank to the former elements. It is in the power of the combination, to know, of the relation, where Hayek finds the key of perception, and thus, the sensory order. He does it forcing the psychology “of mosaic” to take a Copernican turn around. In the new psychology of perception he proposes, there are neither elemental sensations nor sensational nucleuses à la Mach. All perception, even the more elemental, are based on the relations or contiguousness or simultaneity between the stimuli or impulses to which the object has been subject in its own past or in the past of the species. It is here where Hayek finds the fulcrum for the Copernican turn: in the evolution of species and the individual, to know, in phylogeny and ontogeny. There is nothing new in the world of the senses. Everything we feel and perceive is of associative character, is the aggregate of relations that have been formed between stimuli that have occurred at the same time and at the same historical places of the species or the individual organism. At the lowest levels, the primary sensations are based on simple relationships that in the course of evolution have established relationships of contiguousness or spatial or temporal continuity. This is how the temporal sensors and the sensory receptors of the optical thalamus and the cerebral cortex are formed. These structures constitute, to put it this way, the memory of the species, the filetic memory or evolutionary, which was formed during the “night of time” in order to better adapt the species to the vicissitudes of the environment. Above those lowest levels of the sensory order, presumably in the so called cortex of association, the systems of relations are being formed between stimuli, let’s say it now, the networks of perceptive individual memory (in a psychological plane, Hayek calls them maps) that store in its structure the memory of the individual, plastic, dynamic and open to the future, subject to constant change until death. Each stimulus, each memory, according to Hayek, evokes its “retinue”, to know, a host of sensory traces that one day accompanied that stimulus or other similar ones (similarity, according to James Mill, is a special circumstance of cooccurrence) and that contribute to the map or network to which the stimulus belongs. When that stimuli and other similar ones reappear in the sensory environment, triggered by associative relationships of the original network, with which triggers the entire stimuli of perception, bringing about in unity the whole perception. With which, furthermore, the network opens to new accompanying stimuli that will amplify or bring “up to date”. Definitely, according to Hayek, to perceive is to classify the world in groups of relations among stimuli previously formed in the history of the organism or of its species. And the nervous system, or its part that is dedicated to perception, from sensory organs to the associative cortex, is essentially a classifying apparatus of relations among stimuli. Perception of an object is defined by the relations among the sensory components of the object. By itself, those components have no mental quality, but together they do. With it, theoretically, a problem that has perplexed psychologists since immemorial times is resolved: the problem of constant perception. How is it that the object continues to be the same in spite of its change of color, of its dimensions and of the space it occupies in the retina? How is it that the melody is the same even though the key, the scale or the instrument that emits it changes? The explanation is found, naturally, in the relation and order of the components. During the years that passed between the time this book’s draft was written and its publication in 1952, there appeared in Europe two important intellectual currents that Hayek used extensively to support and extend his psychological theory. The first was the Psychology of Form or Gestalt (Gestalt psychologie, Koffka, 1935); the second, Biology of the Systems (von Bertalanffy, 1942). The Gestalt psychologist reasoned that the object of perception was the figure, form or structure. They based their concepts, above all, in the field of vision, where an object and its perception are not formed simply by the apposition of elemental luminous impressions of the object on the retina, but by the configuration of those impressions, to know, as result of the order and relation among themselves. The concept of Gestalt, consequently, goes beyond the heralded saying, “the whole is more than the sum of its parts”, which is undoubtedly true. Better to say, the whole is defined by order and the relationships among the parts. Hayek goes even farther. In the first place, he rids Gestalt of the nativism attributed by the founders, who postulated that “forms” have innate representation in the central nervous system, and this representation would manifest itself in the form of hypothetical “electrical fields”. Hayek rejects such concepts, that have no empirical foundation, but without refuting principal elements of Gestalt, and above all maintaining and emphasizing, among them, the relational or associative character of perception. At all levels, from the most elemental up to the most abstract, perception consists of a sensory order that has been formed in the nervous system by classifying acts of the surrounding, that is during the course of history of the species or of the individual. Gifted with the attributes, the relational and the evolutional, Gestalt becomes to Hayek the theoretical foundation of his conception of the sensory order and perception. It is important to add that, though the Gestalt psychologies built their theory almost exclusively in the visual environment, Hayek extended it and applied in all sensory environments. It remains to clarify the neurological base of these theoretical connections, of those relations among sensations that form the networks or “maps” of perception—and now that of the memory—that Hayek postulates. The second intellectual movement that decisively influenced Hayek is the socalled Biology of Systems. This current of thought had its origins in the work of the great philosophers and biologists of the end of the XIX and beginning of the XX centuries (e.g.; Bernard, Cannon, Uexküll). Among them, the one that most influenced Hayek was von Bertalanffy (1942). The fundamental concept of his theory is his theory of organization. The structural and functional properties of a biological system derive from the relations among its components and not from the individual properties of its components. In other words, the meaning of the structure and functions of a system reside exclusively in the organization of its parts and are inherent to it. The conceptual affinity between the systems theory and Hayek’s psychological theory is immediately understood. For him, all sensory order, all perception, are based in the relations among elements, more or less complex, and in their organization in the form of cognitive networks. What is important are the elements and, above all, the relations among themselves. To explain the formation of the contacts in his networks of perception and memory, Hayek uses an old concept of Ramon Cajal that was one of the first, if not the first, in proposing: the synaptic modulation by experience. In his Remembrances of My Life (1923, p. 288) he tells us, possibly paraphrasing him, what he told the participants to an international meeting in Rome with respect to the formation of habits and motor memories: “the functional perfection brought on by exercise (physical education, operations of speaking, writing, playing the piano, mastery in fencing, etc.) [...it is due to] the creation of new cellular appendices [...] susceptible of improving the adjustment and reach of the contacts, and even of organizing absolutely new relations between neurons primitively unconnected.“ All this Cajal said before Sherrington would invent the word “synapses” to describe those “contacts” between neurons. The fundamental idea is that the formation and consolidation of memory are due to the connection of synapses. Preceding Hebb (1949)—in the fact that this concept would be already mentioned in original version of The Sensory Order—Hayek proposes the beginning of the temporal coincidence of sensory impulses, and in the formation of memory, in order to facilitate the synapses between the neurons that received simultaneous impulses. This concept is completely backed today by data gathered by neurophysiological experiments on animals (summarized by Fuster, 1999). With relatively recent neurophysiological data, about which we cannot expand here, the basic fundamental physiological of association in memory, and subsequently, of the formation and recall of memories has been substantiated. Curiously, it was another Spaniard, Juan Luis Vives (1538), who already in the XVI century had enunciated the principle of simultaneity in the association of the perceptive mind, when he said: “Quae simul sunt a phantasia comprehensa si alterutrum occurrat, solet secum alterum representare” (Of two things simultaneously learned, if one happens it usually evokes the other.) Modern neuroscience gives that saying as its cerebral support. Just as it is done to support Hebb’s and Hayek’s principles of synaptic plasticity. Hayek, in his book, postulates that somewhere in the nervous system, probably in the cerebral cortex according to him, exists a structure and functional isomorphic organization with the organization of its sensory maps and networks. The isomorphism that he proposes is a topological isomorphism. With it he means to say that two hypothetical networks, one mental or perceptive and the other that represents in the cortex, coincide topologically, in such a way that order and relations between elements (nodes) in one are identical to order and relations between the other; I say order and relations, not physical distances between elements—which in a network are sensations and in the other are assemblies of neurons. Hayek makes us imagine two networks of knotted elastic networks, where the knots and the connecting pieces between the knots in one correspond to the knots and connecting pieces of the other. The two networks are topologically isomorphic, thus stretching and twisting any which way one of them, this one retains its topology and its isomorphism with the other. In the same manner, the sensory order would correspond to isomorphic order in the organization of the cortex. The organization of the cortex that Hayek insinuates in this book, like the role played by synaptic plasticity in learning and memory, would later find its neurobiological base in the cortical connectivity that was discovered much later after the book’s publication. It is truly astonishing that its author, in the middle of the ignorance that existed in the first half of the XX century about the anatomical and physiological organization of the cortex, would instinctively coincide with the evidence of the second half of the century. In cognitive neuroscience, as in other fields of human knowledge, the genius of Hayek is in having anticipated with perspicacity what would be verified many years later after it was stated at the theoretical level. During the three decades that passed during 1960 and 1990, new methods were designed to trace nerve connections in the primate’s cerebrum, which is in many ways homolog to the human. In several laboratories around the world, it was discovered with these methods a wealth of connections, unsuspected previously, among the different cortical areas. Each assembly of neurons, in any part of the cortex, seemed to be connected directly or indirectly with whichever other. Furthermore, the connectivity was reciprocal; an area that sent connections to the others, receive them in return, the major part of the connections were short, lacing connections or contiguous areas. Many of the connections, never the less, were long, lacing different areas among themselves, such as the frontal lobe areas, with the occipital, or the temporal ones. Little by little, never the less, in that huge mass of nerve fibers, a certain order was discovered. In first place was seen, that certain areas, to know, the sensory and primary motor areas, those we previously called the seat of the “filetic memory”, are the origins of nerve fibers that cross from area to area toward the more elevated zones of association or integration of the temporal, parietal and frontal lobes. It was also seen than each succession of areas in such discontinuous trajectories form a connective road and an information processing way that goes from an area primary sensorial or of determined motor modality (vision, tact, etc.) towards the cortex of association, supposedly processing and moving higher toward the superior information or motor areas of each modality. It was seen that at each step in the trajectory, the neurons from one area did not only transmit to fibers backwards to preceding area; but, more over, it transmitted collaterally to other sensory roads, as well as, other neurons at superior areas. Definitely, it appears to be that from each primary cortical zone, whether it be sensory or motor, departs an inverted conical weave of connective and neural processing that widens and distributes as it progresses, interconnecting itself with areas of association each time higher and more poli-modal. There is more, that progression toward the high cortical areas continues not only with gradient connections, but gradient in evolution and development, that is to say, filogenetic and ontogenetic. The lowest areas (“filetic memory”) are the ones that develop before, not only during the course of evolution; but, as well as, during the course of perinatal development. The higher areas, those of the superior associative cortex, are the ones that develop more and much later, in the evolution, as well as, during the development of the individual. The frontal cortex, for example, does not reach its maximum development up until the human cerebrum, and itself, until the third decade of life. It is along the length of these three gradients—connective, filogenetic and ontogenetic—how, from the beginning of the primary sensory and motor cortex, the networks of perception and memory are formed from the bottom up. Experiences that happen at the same time strengthen the synaptic contacts between the assemblies of neurons that receive what those impulses generate. New experiences, by association, reactivate old networks, expanding and reconfiguring the latter. The memory network each in its turn more complex and more abstract grow superimposing one above the other toward levels each time of higher cortical representations in the areas of superior associativity. All this constitutes a dynamic network formation process that retains memory in its connective tangle and at the same time serve to perceive, that is to say, to interpret and classify, the new experiences in the context of previous established memories. At the root of this dynamic network formation process, by which what is sensory— like that, which is motor—becomes mental, is the easiness of connectivity between neurons. It is because of this selective ease of synapses in this huge connective structure of the cortex how the memories of the individual are formed on the filetic memory base—sensory cortex and primary motor—that is common to all individuals of the species. The idiosyncrasy and specificity of the memory of the individual resides in the ability of each individual to combine the ten thousand million or so neurons that reside in the human cortex. As Hayek premised, the process of the formation of cognitive networks is a self-organizing connective process of the cortex under the influence of experiences. Under the use that experience imposes, the synapses between neurons simultaneous activated are facilitated, by which the network that unites them are formed or strengthen. It is, thus, with use how, the immense connective substrate that is in good part indefinite nerve roads, make their own roads that constitute the network and defines it. Things happen in somewhat the same way as the poet used to say: “Traveler there is no road, it is made as you walk” (Antonio Machado, Campos de Castilla). That dynamic formation of cognitive networks, whose consolidation does not seem to stop during dreams, leads to the organization of the sensory order in the cortex similar to the one espoused by Hayek with much less knowledge, compare to what we know today, about the marvelous structure of the human brain. From our neuroscientific perspective of the XXI century (Fuster, 2003), the cognitive networks that he postulated, serve perception as well as memory, appear organized hierarchically, intertwine between themselves and sharing neuronal assemblies (the “knots” of the net) in very distinct levels of the hierarchy. The lowest networks of the hierarchy, those that represent more concrete memories, sensory as well as motor, reside in primary cortical areas and in foreign areas, the sensation entry points in the cortex and the exit points of the motor cortex to the kinetic apparatus. Above this network, in the associative sensory cortex, the more complex associative memories are found “declarative”, episodic and semantic; and associative motor cortex; one finds the memory that executes programs and sequential actions. Lastly, in the superior levels of the associative cortex of the parietal, temporal, and frontal (prefrontal cortex) lobes, reside the more abstract networks, representative of general concepts and action plans. All the levels of networks keep connected among themselves and the common nodes, by which and assembly of neurons, practically in any part of the cortex, can be part of many networks, and consequently of many memories. Thanks to modern neuroscientific methods, today we know that the function of the networks or neuronal “maps” of cortical representation that Hayek proposed to explain the sensory order in the human mind transcends perception and memory. Neuro-imaging and electro-physiology in man and primate permits us to affirm that to those two functions it is necessary to add attention, intelligence and language. It is to say, that the five cognitive functions are the result of selective and orderly activation, in time and cerebral space, of the cognitive networks that represent our internal and external worlds. Taking into account the little that was known in his time about the cerebral cortex, Hayek was not able to know the precise order that reigns in the structure and function of those networks, but he guessed with masterful precision the principles of that order or, to say it his way, “the explanation of the beginning”.