I - SCIENCE IN THE CLASSROOM, FOR EARLY CHILDHOOD AND PRIMARY EDUCATION TEACHERS. I: THE GENERAL NATURE OF KNOWLEDGE

1 SCIENCE IN THE CLASSROOM, FOR EARLY CHILDHOOD AND PRIMARY EDUCATION TEACHERS. EL CSIC EN LA ESCUELA I: THE GENERAL NATURE OF KNOWLEDGE María José Gómez Díaz El CSIC en la Escuela, Vicepresidencia Adjunta de Cultura Científica y Ciencia Ciudadana Consejo Superior de Investigaciones Científicas (CSIC) María Pilar López Sancho Instituto de Ciencia de Materiales de Madrid (ICMM) Consejo Superior de Investigaciones Científicas (CSIC) José M. López Sancho Instituto de Física Fundamental Consejo Superior de Investigaciones Científicas (CSIC) [email protected] ABSTRACT CSIC en la Escuela is an international program of the Spanish National Research Council (CSIC) based on the collaboration between scientists and teachers. Its goal is to provide scientific training for preschool and primary school teachers, conceiving science as a means to achieve equality, inclusion, and social justice. From a STEAM perspective, the program also highlights the relationship between scientific, technological, and social revolutions, which are essential when designing the education and content to be provided to citizens. In schools, where relationships have a strong emotional component, the figure of the teacher acquires an endearing quality that lasts throughout life. Who does not fondly remember their first teachers or first friends, in an environment where sharing, respect, and cooperation were learned beyond individual differences? It is in this setting that learning models, love of knowledge, attitudes, and values are internalized elements that define, illustrate, and permeate the program. These models also play a major role in students’ socialization, which makes education in equality essential, fostering collaboration and eliminating gender stereotypes and other biases. This is the first of four articles outlining an interdisciplinary pedagogical proposal for teaching science in early education, developed within the program. By integrating 2 contributions from the philosophy of knowledge, cognitive developmental psychology, neuroscience, and linguistics, it argues that scientific knowledge has a structure analogous to that of a language, with a double meaning for each signifier. This feature allows science to be approached as a second language, with classroom research becoming the place and the practice through which it is learned. Teacher awareness is crucial in this regard, particularly for eradicating linguistic barriers that unconsciously transmit traditional biases of gender, class, or race, among others. Drawing on the contributions of authors such as Kant, Piaget, Vygotsky, Chomsky, Saussure, and Quian Quiroga, as well as on our own experience, the program proposes an educational model centered on conceptualization and cooperative learning. The proposal emphasizes the creation of inclusive and egalitarian school environments that stimulate curiosity and symbolic thinking from early ages, for which teacher training is essential. Regarding the purpose of science education, we agree with Nussbaum and Margulis that an education focused solely on productivity perpetuates inequalities and limits human development. In contrast, we advocate for a critical and humanistic education that fosters empathy, autonomous thinking, and free citizenship, making knowledge a tool for emancipation. Nevertheless, we must acknowledge that science may be allowed in schools precisely because, for those who govern society, its teaching is productive; our task, therefore, is to take advantage of this opportunity to pursue our own goals of equality and inclusion. Keywords: science education, scientific language, cognitive neuroscience, philosophy of knowledge, Kant, Piaget, Vygotsky, conceptualization, early childhood education. 1. INTRODUCTION Both the mystery of learning and the art of teaching rest upon the enigma of epistemology—the nature of the knowledge that human beings possess about the world around us, how we construct that knowledge, and how we employ it to navigate within that world. Thus, teaching, learning, and epistemology are the three pillars responsible for the rapid development of our societies, from the Neolithic revolution to artificial intelligence, in an ascending spiral that almost induces vertigo. The same occurs if we approach the problem from a personal point of view. Our lives unfold within such a narrow window of time and space that it scarcely allows us to satisfy our desire for knowledge. It is necessary to look outward and learn, even if only through descriptions, about other places and other times in order to satisfy what seems to be the very essence of our nature: curiosity. Bernard of Chartres, in the 12th century, referred to the importance of transmitting knowledge from one generation to another with an expression that Isaac Newton later made famous: If I have seen further, it is by standing on the shoulders of giants. * For this reason, from the very moment human society possessed knowledge worthy of being transmitted to future generations, it began to reflect upon the problem of teaching. Without this intentional transmission, each generation would be condemned to begin 3 anew, making it impossible to achieve the progressive accumulation of knowledge (the fundamental mechanism of our adaptation to the environment) and, with it, the cultural, scientific, and technological development of humanity. These considerations place teachers at the most important point in History—with a capital H—on the line that separates the past from the future, at the precise moment when that intergenerational transmission of knowledge must take place. To them, particularly to those who dedicate their work to the earliest stages of education—the most decisive moment in the cognitive development of human beings (Shonkoff & Phillips, 2000)— these pages are addressed, in the hope that they will prove both useful and enjoyable to read. 2. THE NATURE OF KNOWLEDGE Teaching and learning are two complementary processes. Teaching involves analyzing the knowledge to be transmitted, dissecting it, and breaking it down into the fundamental concepts that compose it, in order to organize them as one would design the blueprints of a multi-story building, from the foundations upward, from the simplest to the most complex. Learning, in turn, means assimilating those concepts and using them as building blocks to construct new knowledge in an orderly manner. But just as designing buildings requires knowledge of the art of architecture, teaching requires familiarity with epistemology—the science of knowledge. This inevitably leads us to the fundamental question: What is knowledge? Perhaps the most brilliant definition we have (in this case applied to physics) is Einstein’s. In the preface to his book The Evolution of Physics (Einstein & Infeld, 1938) he states: Physics is an attempt to represent the external world in the mind We take advantage of this brilliant definition to broaden it to knowledge in general. We define knowledge as the representation of the external world in our minds, so that this representation mimics as closely as possible the nature of the outside world, what happens in it, and the way it happens. Footnote: According to John of Salisbury in Metalogicon (1159), Bernard’s phrase was: “We are like dwarfs perched on the shoulders of giants. In this way we can see further than they, not by the sharpness of our own sight or the height of our bodies, but because we are lifted up by their great stature.” 4 Einstein, deeply interested as he was in the problems of time and space, knew Kant’s (1724–1804) work very well, so it is logical that his definition of physics should bring us back to the latter, often regarded as the first constructivist. But before that, it is worth making a few brief reflections. The role of philosophy in teaching and learning processes We can affirm that, just as technologies are grounded in scientific theories, every teaching method rests upon a theory of knowledge—that is, an epistemology. This has been the case since classical Greece, when the two great epistemological approaches emerged that have persisted throughout the history of Western thought and decisively influenced pedagogical conceptions: rationalism and empiricism. Rationalism, represented mainly by Plato, held that the soul, before becoming incarnate, dwelled in the world of Ideas, where it knew the pure Forms: eternal, perfect, and immutable essences that constitute the true reality of all things. As a consequence of that prior existence, we retain in the depths of our minds an unconscious memory of those truths. We hold them in our memory without being aware of them; it is necessary to search within ourselves to recover them, like someone who, in an archaeological excavation, slowly removes the earth covering a statue before being able to contemplate it. This model of epistemology, poetically described in the Meno (Plato, 390 BCE/1991), gave rise to the pedagogical method known as anamnesis, according to which learning is equivalent to remembering what the soul already knows without knowing that it knows it. In the educational sphere, this theory translates into the use of the Socratic method, which every teacher skillfully employs when the situation requires it. Socrates referred to this art—perhaps with a touch of humor—as maieutics, a Greek term meaning “the art of assisting in childbirth,” since he considered teaching to be like helping give birth to the ideas and knowledge that the learner already carries within. In contrast with rationalism, empiricism, universally associated with Aristotle, maintains that the human being is born as a tabula rasa, that is, with the mind as a blank slate, devoid of content, and that consequently all knowledge is the product of observation and experience. For Aristotle, nothing exists in the intellect that has not first passed through the senses (De Anima, 2007). The two currents have persisted through time as true memes in Dawkins’ sense (units of cultural information transmitted from one person to another in a manner similar to the way genes transmit biological information) (Dawkins, 1976). These two theories of knowledge have been replicated, adapted, and reformulated across different epochs and have come down to the present day as alive as when they were first conceived. 5 3. KANT, THE FIRST CONSTRUCTIVIST: INFORMATION VERSUS KNOWLEDGE In his Critique of Pure Reason (Kant, 1782/2004), Immanuel Kant sought to resolve the dispute between rationalism and empiricism through a transcendental synthesis, the study of which is the foundation of all subsequent treatments of knowledge. As we pointed out in the previous section, Einstein’s idea of science can be seen as a particularization of Kant’s theory of knowledge, with which Einstein was thoroughly familiar. This familiarity stemmed not only from his education at the LuitpoldGymnasium in Munich—where philosophy was part of the classical curriculum and Kant was a central figure—but also from the interest they both shared in the nature of space and time, which makes it natural to establish a link between their approaches. Einstein’s vision, which we may define as moderate realism, postulates that the role of science is to discover the laws of nature, which exist independently of human observation. For us, this is the basis of Kant’s constructivism, which we will now address. Kant defines the scene of knowledge as consisting of two clearly differentiated parts: an external world, which we wish to study and which we assume to be real, and an inner world, where thought resides and which we identify with the mind of the subject who seeks to know. These two parts are separate, though connected through the senses, a kind of windows through which we receive the only information available to us from the outside world. In this mind we construct a necessarily simplified representation of the real world. What are objects in the external world become ideas or images— mathematical in nature—more or less specific or general, in the inner world. Let us summarize: what reaches us through the senses is information about the world; the representation we construct in the mind constitutes knowledge. 1. Kant’s definition of knowledge is that of a representation in the mind of the external world, which we assume to be real. From this perspective, the effectiveness of such representation depends on our ability to retain the essential features of reality and to disregard the incidental ones. 1. Kant’s definition of knowledge is that of a representation in the mind of the external world (assumed real), necessarily highly simplified. From this perspective, the effectiveness of such a representation depends on our skill in retaining the essential characteristics of reality and disregarding the accessory ones. 2. The accuracy of this knowledge is reflected in how precisely the outcome of real processes simulated in our minds matches the results of actual processes. The history of science, from this perspective, is the chronicle of the efforts and skills of philosophers and lovers of truth who, throughout time, have striven to perfect that representation. 6 3. This representation is constructed by each person through the processing of signals emitted by external things (what Kant calls noumena), which reach the mind through the senses—not necessarily identical for all people. This transforms the very nature of teaching, which ceases to be a process of transmitting knowledge and becomes instead an aid to the personal construction of knowledge by the learner. 4. The processing and ordering in the mind of the signals provided by the senses (phenomena, according to Kant’s theory) is carried out through an innate system of categories adapted to the brain’s capacities—such as time, space, and causality—which analyze and organize them accordingly. These signals (information) are thus transformed into mental representations of external things, like images or sounds, suitable for storage and manipulation by the mind, and they form the basis of our representation of the world in our imagination (knowledge). An analogy: the mobile phone If we apply Kant’s ideas to the case of a mobile phone, we might say that the camera (its only sense, in this case) captures images of objects in the external world (noumena in Kantian terms). The result is a series of electrical signals produced by the image sensor (phenomena), which are processed and stored in the phone’s memory (the photo library) in the form of ones and zeros (appropriate for the type of chips that make up its memory). These images are arranged and organized according to the place (space) and the date and time (time) at which they were taken (the phone’s categories), so that they can later be retrieved to reconstruct the original story or to create new ones based on those same images. In this case, the photo library constitutes the knowledge (representation) that the phone has of the external world. However, the information received from the outside is reduced to that part of the world that can be photographed and processed, subject, therefore, to the limitations of capture and processing. These limitations may arise at two levels. On the one hand, in the physical capacities of the sensory system (the lens and the image sensor), which, for example, may block certain wavelengths such as ultraviolet or infrared. On the other hand, in the capacity to categorize the signals sent by the image sensor. In this case, identification requires the categorization of the colors red, green, and blue: three innate categories the phone must possess. If it only had the category of light and darkness, its knowledge would be limited to black-and-white vision. Similarly, the precision of spatial location depends on the accuracy of the GPS, and temporal accuracy on the resolution of the internal clock. The result is, therefore, a filtered representation, conditioned by the technical limits of the system. This limitation is analogous to those described by Kant for human beings. Any characteristics of signals that do not correspond to the categories we possess are lost. 7 Everything that falls outside space and time—or other categories of understanding as organizing structures of experience—is as if it did not exist (Kant, 2003). With this analogy, we have sought to illustrate Kant’s position, which breaks with pure empiricism and rationalism while retaining elements of both. • He rejects empiricism because knowledge is not a passive copy of what the senses capture, but an image processed by the innate categories of space, time, and causality. • He rejects rationalism because knowledge is not present in the mind before experience. The categories are useful only for processing information that arrives from outside. The transcendental synthesis Thus, Kant arrives at his transcendental synthesis: knowledge arises from the interaction between the information obtained from outside (which retains something of Aristotle’s empiricism) and its organization according to innate categories (Plato— always Plato). Kant summarizes this position in his famous statement: “Knowledge begins with experience, but not all of it arises from experience.” Experience provides the data, but the mind organizes them through pre-existing structures. Kant calls this way of considering knowledge transcendental idealism (Critique of Pure Reason, 1781). Here, the term “idealism” does not imply denying the existence of the external world but rather affirming that we know it only as it appears to us, always mediated by the senses and by our mental structures. This is what he called the Copernican revolution in knowledge. Just as Copernicus inverted the Earth–Sun relationship, Kant inverts the relationship between the subject and the object of knowledge: instead of the mind passively adapting to objects, it is the objects of experience that conform to the subject’s forms of knowing. As in astronomy, where the Copernican revolution altered the interpretation of observations without changing the data, in philosophy this revolution radically transformed the understanding of the relationship between thought and reality. Kant as constructivist and “impressionist” In light of these considerations, we may say that Kant is not only the first constructivist but also—as Manet said of Velázquez—the first impressionist. His philosophy presents knowledge as referring only to how we see the world, not to how the world truly is. Just as pictorial impressionism does not seek to reproduce objective reality with exactness but to capture the subjective and momentary visual experience it produces in the observer, 8 Kantian philosophy does not describe the world as it is, but as it appears to us, filtered and shaped by the structures of our mind. In reality, if we think carefully, the differentiation between the real world and its mental representation is neither evident nor immediate, and it has historically been the subject of debate among different philosophical schools. But Kant, as we have seen, put an end to this controversy (González, 2024). Human development appears to follow the same path as the history of knowledge. During the preoperational stage (approximately between 2 and 6 years of age), children are in a phase we might call pre-Kantian, characterized by the belief that the world they know and navigate is the world itself, just as it is. The task of the teacher is to guide them, adapting the learning process to their cognitive development, so that they travel the philosophical path leading them to develop for themselves the Copernican revolution as Kant described it: to understand that knowledge of the world is always mediated by the senses, the structures of the mind, and even beliefs, and thus not to trust it blindly. 4. A FUN AND THOUGHT-PROVOKING REFLECTION: THE PROBLEM OF SOLIPSISM Kant maintains in the Critique of Pure Reason (1781/1998) that human knowledge consists in a representation of the external world in the mind. However, this raises an interesting question: how can we be sure that our representation corresponds to an external reality and is not merely the product of imagination without any real referent? This gives rise to the doctrine of solipsism, which serves more as a test of philosophy’s ability to demonstrate the obvious starting from Cartesian doubt (Nagel, 1986). Solipsism originates in the radical doubt formulated by Descartes in his Meditations on First Philosophy (1641/1996). For the French philosopher, everything can be subject to suspicion—senses, memory, even mathematics—except the very fact of our existence: cogito ergo sum. One cannot go beyond this; both the external world and other minds might be nothing more than the product of a deep dream. From our point of view, the most original refutation of solipsism is that of the existentialist Jean-Paul Sartre. In No Exit (Huis clos, 1944/2005) he introduces his famous phrase “Hell is other people”, with which he describes the conflict generated by the freedom of others in relation to our own. He develops this idea in a more didactic way in The Respectful Prostitute (La putain respectueuse, 1946/1997). According to Sartre, others must exist, for otherwise it is inexplicable that we perform actions contrary to our own morality and way of thinking. This can only be explained by the violence that they exert upon us. 9 5.- PIAGET’S REVOLUTION AND THE OPENING OF A NEW EPISTEMOLOGICAL PATH Once Kant’s view of knowledge as a representation of reality in the mind was accepted, Jean Piaget (1896–1980) reformulated the problem of categories from a completely new biological and psychological perspective. He realized a fundamental error—difficult to conceive today: for centuries, philosophers had considered only the adult as the subject of knowledge, reducing the child to a mere “adult without experience.” Piaget proposed that, if one wished to understand the cognitive capacity of our species, it was necessary to investigate the genesis of the structures of thought. Kant, in the Critique of Pure Reason, had argued that categories such as time, space, or causality do not come from experience but rather constitute the conditions of possibility for knowledge. Piaget, trained in biology and psychology, went a step further: he asked how and when those categories emerge in the development of the individual, thus opening a new line of inquiry that would culminate in genetic epistemology. This methodological shift opened an unprecedented field of research: the study of the progressive formation of cognitive categories from birth to adulthood. Piaget carried out this work with systematic rigor, founding genetic epistemology as a discipline. His career combined biology—his initial training, in which he earned a doctorate in 1918 with a dissertation on mollusks—with developmental psychology, the discipline he embraced after collaborating with educational institutions. One decisive experience was his work in 1921 at Maria Montessori’s school in Paris, where he came into contact with pedagogical methods that valued the child’s autonomy and the direct observation of learning processes. That same year, he joined the Sorbonne (1921–1925), where he collaborated on the development of psychometric intelligence tests. It was there that Piaget noticed a revealing pattern: children of the same age made similar errors in logic tests, regardless of their background. In his own words: “The error is not, in these cases, an accidental defect, but the manifestation of a mental structure still in formation” (Piaget, 1947/1978, p. 56). This finding led him to conclude that knowledge does not arise from a passive copy of reality, but from an active process of progressive construction, dependent on the cognitive capacity available at each stage. Consequently, the way in which boys and girls engage with knowledge of the external world is transformed throughout their development, as new mental structures emerge that allow them to understand reality in a more complex and accurate way. Epistemology is different for an adult than for a child. His hypothesis was reinforced by a biologically inspired analogy. In 1899, Ernst Haeckel had formulated the so-called “fundamental biogenetic law,” according to which ontogeny recapitulates phylogeny: the embryonic development of an individual reproduces, in abbreviated form, the evolution of the species. Although this theory was later revised in biology, Piaget adopted it as a powerful heuristic metaphor. In his proposal, cognitive 16 The narrator tells us: “At the age of nineteen he had fallen from a horse on the San Francisco ranch and was left crippled, unable to move or speak; a week later he recovered speech and mobility, but then we realized he had changed.” This change after the accident is what Borges presents as Ireneo’s gift (or curse): absolute memory without the capacity for abstraction. The accident thus marks the moment of Funes’ transformation into a being radically different from ordinary humans, trapped in a hyperrealistic perception of space, time, and reality. His mind, saturated with irrelevant details, is incapable of abstracting, comparing, or generalizing. Borges writes that he was “the solitary and lucid spectator of a multiform, momentary, and almost unbearably exact world.” Funes cannot conceive the concept of “dog,” because every dog he has seen has specific differences—its coat, its posture, the time of day, the perspective—that make it a unique and unrepeatable entity. With this story, Borges demonstrates that memory without conceptualization is useless for knowledge: without categories that group diverse entities under common notions, the world becomes unmanageable for the limited human mind, an infinite succession of individual data without order or hierarchy, impossible even to retain in our limited memory. For Aristotle, knowledge begins with experience, but does not end there; through that mysterious capacity for conceptualization, he tells us, the soul abstracts universal forms from the multiplicity that exists in the real world. Funes, by contrast, remains stuck at that first level. In Kantian terms, we could say that he lacks the categories of understanding that, according to the Critique of Pure Reason, make the synthesis of experience possible. In short, to conceptualize is to classify reality into sets that group an infinity of possible elements (such as all the dogs that have ever existed or could exist) and assign them a name. This ability constitutes one of the fundamental pillars of human thought, of language, and of knowledge. Conceptualization as the Formation of Classes of Things in the World From the earliest years of life, human beings show an extraordinary ability to abstract, categorize, and name the surrounding reality. Although it has been widely studied in philosophy and cognitive sciences, conceptualization presents two complementary mechanisms: on the one hand, the formation of classes or sets based on similarities, such as the aforementioned concept of “dog”; on the other, the preservation of the identity of a particular thing over time, even as its form or composition changes, as occurs with people—my dog remains my dog even as it grows from a puppy into an adult. An example of the first mechanism can be observed in an everyday scene: a little girl whose family has a dog named Ney. At first, for her, “Ney” is simply the proper name of her pet, a unique signifier associated with a specific individual. However, upon seeing other dogs, she begins to call them all “Ney.” In her mind, the name has shifted from 17 being a proper noun to a common noun, from being an individual identifier to a general category. This phenomenon reveals a process of conceptualization through classification, in which the mind groups different entities into the same category based on shared perceptible properties: four legs, snout, bark, fur, etc. (Li & Xu, 2024). Jean Piaget (1952) described this type of operation as a fundamental step in cognitive development. The child builds schemas that allow her to interpret new elements (dogs unknown to her) based on prior mental structures (her dog Ney). This type of conceptualization is essential not only for language development but also for the formation of semantic categories and the construction of logical thought (Vygotsky, 1962). Conceptualization as the Permanence of Identity There is, as we have said, another dimension of conceptualization, less evident but equally essential: the ability to preserve the identity of a thing over time, despite its transformations. Borges writes of Funes: “It was not only difficult for him to understand that the generic symbol dog embraced so many different individuals of various sizes and shapes; it irritated him that the dog of three fourteen (seen in profile) had the same name as the dog of three fifteen (seen from the front).” To this persistence of the concept over time we now turn our attention. This need to categorize reality and preserve identity over time already appears in the origins of Greek thought. Heraclitus of Ephesus, one of the earliest pre-Socratic philosophers, formulated it in his famous dictum: “No one ever steps in the same river twice.” Heraclitus observed that although we cross “the same river” again, neither the water is the same nor are the pebbles on the riverbed, nor the shape of the meanders, which sometimes grow or disappear forming lagoons. The river is constantly changing— the water flows, the riverbed shifts, the environment varies—and yet we continue to identify the river by the same name. This phenomenon is only possible thanks to a second-order abstract operation. Although the Meander River, for example, changes shape over time, each of its particular configurations still corresponds to the concept of “Meander River.” If we were to take aerial images of that same river over a thousand years, each photograph would show something different, but in all of them we would recognize the same Meander River. All would form a subset within the general concept of river, which we continue to call by the name of its oldest representative. The same occurs with people: despite physical, psychological, and biographical changes, we maintain an identity over time and are known by the same name. This form of conceptualization underlies object permanence (Piaget, 1954) and all its consequences. 18 Quian Quiroga: The Neuronal Representation of Concepts In recent years, cognitive neuroscience has empirically confirmed many philosophical and psychological intuitions about how knowledge is represented in the mind (Gazzaniga, Ivry, & Mangun, 2019). A key discovery in this direction is that of the so-called “concept cells,” made by neuroscientist Rodrigo Quian Quiroga (Quian Quiroga et al., 2005; Quian Quiroga, 2017). These neurons, also known as “Jennifer Aniston neurons,” were identified in epileptic patients undergoing intracranial recordings to locate abnormal activity. Remarkably, certain neurons in the medial temporal lobe, particularly in the hippocampus, consistently fired in response to very different stimuli referring to the same concept—for example, the same neuron responded to a photograph, the written name, or the spoken voice of “Jennifer Aniston,” but did not react to similar stimuli related to other people. This finding is revolutionary because it demonstrates that the brain does not store isolated images or sounds but constructs abstract, multimodal representations: concepts, not copies of the world. Thus, these neurons do not merely activate specific memories; they represent meaningful, stable entities that organize our understanding of the world—what we call a concept. In our mobile phone example, we know that the device can identify people in stored photographs, recognizing their faces both in profile and frontally. If, in addition, we associate each image with the corresponding voice, and both categories—visual and auditory—are integrated into a single memory representing that person, that memory would be equivalent to one of Quian Quiroga’s concept neurons, which we might label with the name of the person it represents. From the perspective of knowledge, this confirms the Kantian and Piagetian thesis that we do not merely perceive a continuous flow of stimuli, but rather organize experience into concepts. Quian Quiroga’s neurons are, in a sense, the biological correlate of the conceptual categories that allow us to think, remember, associate, and learn. Moreover, this type of abstract coding has great efficiency: since it does not depend on specific sensory details, the brain can recognize, retrieve, and relate ideas quickly and flexibly. Thus, the hypothesis is reinforced that knowledge is not an accumulation of data but an organized structure of concepts, encoded in an integrated manner through highly selective neurons (Quiroga, 2013). This discovery constitutes a natural bridge toward the next level of organization of thought: language, as a symbolic and structured form of expressing these mental representations. In this sense, Noam Chomsky’s ideas on generative grammar fit perfectly into this architecture of the mind. 19 Conceptualization as a Way of Perceiving and Shaping the World To conclude this section on the nature and function of the concept, we want to highlight its two roles in the construction of knowledge—that is, in the representation of the real world in the mind. On the one hand, as the philosophers of classical Greece already noted, it allows us to store under a single word a large number of elements that share common characteristics, as well as to recognize the permanence of certain entities that maintain their identity over time, even as they change or transform. This cognitive mechanism corresponds to a process of reduction and abstraction: from a virtually infinite number of stimuli and realities, the human being constructs a limited and finite number of concepts as a strategy for mentally representing the world in a manageable way. On the other hand, conceptualization plays an inverse and complementary role, as described by Benjamin Lee Whorf in 1956, expanding on the ideas of his teacher Edward Sapir: the concepts we already have in mind serve as references to identify and classify the things we perceive in the external world. In this sense, they act as a catalog of entities and phenomena that shape the reality we know, so that we only identify in the outside world those ideas that correspond to concepts previously acquired, while others remain practically invisible. The Sapir-Whorf hypothesis was originally formulated with examples such as the multiple terms for “snow” in certain Indigenous languages and suggests that language acts as a perceptual filter that shapes how speakers perceive and conceptualize reality. The central idea is that the structure of language affects cognition—that is, it influences how we interpret and mentally organize the world. From this perspective, if a language lacks a term to designate a particular phenomenon, that phenomenon may go unnoticed by its speakers (Whorf, 1956; Sapir, 1921). As we shall see later, with Chomsky’s formulation, language comes to play a role similar to Kant’s categories in the construction of knowledge. According to feminism, this implies that the absence of certain terms in language—such as “female scientist,” “male nurse,” or job titles historically used only in the masculine form—is not neutral: it can contribute to the invisibility of those roles and hinder their social recognition, especially for young girls. This phenomenon is not limited to the workplace; it also affects other spheres such as politics (e.g., “chairman” versus “chairperson”), sports (“linesman” versus “line judge”), or technology (“fireman” versus “firefighter”), where the lack of or minority use of gender-inclusive terms reinforces stereotypes and consolidates the idea that certain fields belong by default to one gender. Even seemingly neutral expressions such as “businessman” or “family man” carry historical connotations that either erase women’s participation in those roles or assign responsibilities unequally, particularly in the field of science (Keller, Evelyn Fox, 1984/1991; Schiebinger, 1989). 20 This perspective aligns with the arguments of Deborah Cameron (1998) and Robin Lakoff (1975), who emphasize that language can reproduce social hierarchies and gender inequalities, often unconsciously. The absence of words to name certain realities frequently prevents us from perceiving them as possible. Thus, if the concept of a “woman scientist” is missing from the linguistic and cultural repertoire of girls in early education, or if they lack concrete role models who embody that role, the profession may be perceived as inaccessible to them. In their imagination, a woman cannot be a scientist for the same reason she cannot be pope: not because of a lack of ability, but because the linguistic framework that defines reality does not allow for that possibility. Pierre Bourdieu (1991) explains this in terms of symbolic power: language not only communicates but also legitimizes or delegitimizes social realities, determining which ones are visible, possible, and socially acceptable. 9. SAUSSURE: LANGUAGE AS MENTAL STRUCTURE AND ORIGIN OF STRUCTURALISM We have seen that concepts live in the neuronal groups identified by Quian Quiroga and that they are activated when we recall them. Some of these concepts represent things, and others, actions. But how do we manage to set these concepts in motion and associate them in such a way that they describe the activities that occur in reality, presenting them in our imagination like a film? This question was answered by Ferdinand de Saussure (1857–1913) with his theory of the linguistic sign, which constitutes a kind of bridge between the world represented in the mind and the real world. Ferdinand de Saussure (1857–1913) was a Swiss linguist whose work laid the foundations of structural linguistics. He was a professor at the University of Geneva and revolutionized the study of language by proposing that language is a system of interrelated signs within a structure. His approach revolutionized linguistic study by focusing on the linguistic system at a given moment (synchronic), instead of its historical evolution (diachronic). Although Saussure never directly published his theory of language, two of his students, Charles Bally and Albert Sechehaye, compiled his lectures and notes to create the Course in General Linguistics, published in 1916. This posthumous work gave shape to linguistic structuralism and marked the beginning of a new stage in the language sciences (Bally & Sechehaye, 1916). His ideas influenced not only linguistics but also semiology, anthropology, psychoanalysis, philosophy, literary criticism, and more. He proposed a new way of studying language, very different from the traditional one. Saussure sought to understand how language is able to express our thought and transmit it to others. His approach is especially valuable for educators, as it helps us better understand how children learn to speak and to think—something impossible without language (Saussure, 1916/2007). 21 To develop his study, Saussure introduced two new concepts that define the framework of his research program: parole and langue. Parole encompasses all concrete examples of speech: the conversation of a child recounting what they did at recess, the story read aloud, or the song of a girl at play, the speech of a politician, or the descriptions found in literary works. All are examples of parole, what is found in reality. The linguist’s work, according to Saussure, resembles that of a botanist who studies many individual plants to discover how they are organized into families, genera, and species. In the same way, by observing many different uses of words in speech (parole), the researcher can uncover the hidden rules and structures that form the langue, the common system of a linguistic community. These structures manifest in what speakers do unconsciously: the way they combine words, how they order ideas, and so forth. In Saussure’s own words from the Course: “Language is a system of signs that expresses ideas, and is therefore comparable to writing, to the alphabet of the deaf-mutes, to symbolic rites, to forms of courtesy, to military signals, etc. But it is the most important of all those systems.” Following this line of thought, and drawing inspiration from Kant’s philosophy—who argued that we do not know the world as it is, but as we represent it in the mind through concepts we ourselves construct—Saussure defined the basic unit of information in language: the linguistic sign. The linguistic sign consists of two parts: a signifier, which is the sound or written form of the word (for example, dog), and a signified, which is the concept each person has in their mind and which the word evokes, in a somewhat mysterious way. Concepts are not only the atoms of knowledge but also the atoms of language. 22 Today, thanks to neuroscience, we know that when we hear or read a word, the neuron related to that concept is activated, such as the “Jennifer Aniston neuron” described by Quian Quiroga (2017), which we have already mentioned. But we do not only construct concepts of things; we also form those corresponding to actions. As represented in the figure, one can form the concept of running from various particular examples of animals and people running, abstracting the action and assigning it a concept: to run. Conceptualizing always implies an act of abstraction. Thus, the linguistic sign can be understood as the union of three dimensions: the sound or form (signifier), the mental concept (signified), and the cerebral activation that connects them. We all think about the world in terms of concepts that live in our minds—like dog, tree, mom, run—and through the linguistic sign we activate them with words, which we can then organize into structures prefigured by the langue. But a single sign is not enough to communicate complex ideas. That is why signs combine according to grammatical rules to form larger structures, such as sentences. Grammar is the set of internal rules of a language that allow the organization of signs (words) to construct complex meanings and form the structure of language—the langue. The basic unit of transmitting complete ideas is the sentence, something like the molecules of language. It always has two basic components: the subject, who performs the action or of whom something is said, and the predicate, what is said about the subject (action, state, description). This structure is the same one we use to organize in our minds the processes we observe happening in the real world. We divide them by identifying the 23 subject—the one who performs an action—and the predicate—the action that the subject performs. For this reason, structuralism maintains that language reflects the mental structures through which we carry out the representation of the world. Linguistic signs are the symbolic tools with which we structure experience, describe it, and communicate it. It is especially interesting to observe how children in Primary school describe complex processes—ones for which adults use subjunctives and conditionals—using only the indicative with two or three verb tenses, but still organizing them within a correct structure. “I have water and I wet you. I don’t have water and I can’t wet you.” Going one step further, sentences are used to form narratives, which also have their corresponding structure. The simplest example is that of the most basic Western films, with the elementary structure of: boy is alone, boy meets girl, boy loses girl, boy gets girl back—or the more complex ones, like The Labors of Hercules or El Cid. As an extreme case—and surely the most interesting—historians and philosophers study the structure of history itself, trying to identify some pattern in the narrative that might indicate the direction of progress. But that is another story. 10. CHOMSKY: FROM DESCRIPTIVE STRUCTURALISM TO GENERATIVE MENTALISM (Back to Plato) Ferdinand de Saussure studied the functioning of language as a structured system of signs that makes it possible to describe the mental representation we have of the world. However, Saussure did not address why this capacity appears in the human species nor what cognitive basis makes it possible. That step was taken by Noam Chomsky, a young linguist (Philadelphia, 1928)—still with us, and to whom we wish long life—who in the mid-20th century changed the course of the language sciences. His ideas transformed not only linguistics, but also psychology, philosophy, and the very study of the human mind. Against the behaviorist theories that dominated the thought of the time—which held that language was learned through imitation and reinforcement—Chomsky proposed something radical: that human beings are born with an innate capacity for language, a kind of universal grammar inscribed in our biology (Chomsky, 1965). It all began with a critique. In 1959, Chomsky published a devastating review of Verbal Behavior by B. F. Skinner, one of the leading exponents of behaviorism. For Skinner, the ability to speak was simply verbal behavior acquired through conditioned reflexes. For Chomsky, by contrast, language revealed a mental creativity that no stimulus–response theory could explain. How is it possible, he asked, for a child—with limited and often confusing data—to master a complex language in so little time? A child can produce complex structures such as “The dog that was running after the cat that was chasing the mouse is lying in the garden”—even if they have never heard such a sentence. 24 His answer was clear: there must exist prior, innate linguistic knowledge that guides language acquisition (Chomsky, 1959). From this idea, Chomsky developed what he called generative grammar, a formal model that explains how a language can produce an infinite number of sentences from a finite set of rules. To do this, he introduced the distinction between deep structure (the abstract meaning of a sentence) and surface structure (its final form, as we pronounce or write it). Thus, a sentence like “The cat chases the mouse” and its interrogative version “Does the cat chase the mouse?” share a deep structure, but are transformed by specific syntactic rules. Within our narrative, that surface structure is what Saussure studied and what we discussed in the previous section. Over time, this theory became even more ambitious. Chomsky proposed that all human languages share a common basis, a universal grammar that is part of our biological endowment. Through what he called the principles and parameters theory, he explained that learning a language largely consists in setting certain parameters within a system already pre-established in the human mind (Chomsky, 1981). That is why children from any culture can learn their mother tongue with the same ease (Hauser, Chomsky, & Fitch, 2002). By the 1990s, Chomsky began a new stage in his thought: the minimalist program. His goal was even more radical: to reduce language theory to its simplest elements, seeking to explain its origin from an evolutionary perspective. He proposed that a basic mental operation, called MERGE, might be sufficient to generate all possible linguistic structures. From this perspective, language is not merely a tool for communication: it is a profound expression of our mental architecture, perhaps the most distinctive trait of the human species. Chomsky’s work represents a true revolution in our understanding of language. Against views that considered it a product of the environment or a cultural habit, he conceived it as a specific, complex, and universal mental faculty. His thought not only reformulated linguistics as a scientific discipline but also opened new paths for understanding how we think, how we learn, and how we express ourselves. Jerry Fodor’s Mentalese: A Continuation of Chomsky’s Theory After Noam Chomsky revolutionized linguistics by proposing that language is an innate mental faculty, a new question arose: how does the mind think? If speaking requires an internal grammar, might thought itself operate with some kind of symbolic structure? This is the core of the work of Jerry Fodor, an American philosopher and cognitive psychologist, one of the key figures in consolidating modern cognitive science. Fodor deeply admired Chomsky’s work. He saw in him the founder of a truly scientific linguistics, based not on external observation of speech but on the exploration of the internal mental mechanisms that make language possible. But Fodor wanted to go further. In his most influential work, The Language of Thought (1975), he proposed a bold idea: human thought operates in a kind of internal language that precedes any natural language, which he called mentalese. 25 Viewed from our computational theory of mind, mentalese is a low-level language, a kind of assembly or machine code. It is an internal symbolic language, innate and structured, which we use unknowingly every time we reason, remember, or learn. We do not think “in Spanish” or “in Chinese”: we think in mentalese, and then translate those thoughts into our social language. One piece of evidence for Fodor’s theory is that sometimes we have a clear idea in mind but cannot immediately find the corresponding word in our native language. It is possible that mentalese acts as a true operating system that activates or silences concept neurons to produce thought. It may also be that music, another universal language, is interpreted by this low-level code. When we think in mentalese, the corresponding neuronal groups for the concepts we use are likely activated, and to translate those thoughts into ideas we must find the corresponding signifiers—that is, the words that evoke them in whatever language we use. This proposal complements Chomsky’s theory. Chomsky explains how humans are able to generate infinite sentences through internal grammatical rules, and Fodor proposes that the same symbolic capacity is already present in thought: we think in mentalese. In The Modularity of Mind (1983), he modified the computational theory set out in The Language of Thought (1975), arguing that both hardware and software have an architecture composed of modules: specialized systems for specific tasks, such as visual processing, auditory perception, or, of course, language. This idea fit perfectly with Chomsky’s notion of a “language organ”: a biological, specific capacity, evolutionarily designed to acquire and structure knowledge of the external world, which is organized in the same way as linguistic structures. In that sense, the language organ is also the organ of knowledge. Thus, Fodor expanded Chomsky’s work, taking it from linguistics into the philosophy of mind. While Saussure focused on the structure of language, Chomsky studied how it is generated, and Fodor investigated how thought precedes, organizes, and expresses it: language is not just communication—it is the structure of thought. All three shared a mentalist, nativist, and formal vision of knowledge, and together contributed to laying the foundations of what we now understand as cognitive science. The idea of mentalese as a language that operates directly on neurons to manipulate concepts remains current and operative today, with growing support from advances in cognitive neuroscience (Chalmers, 2024; Schneider, 2011). Learning to Speak is Learning to Know: The Mother Tongue and the Representation of the World In light of what we have presented, learning to speak is not a mechanical act achieved by mere repetition of sounds. It is, in fact, one of the first great cognitive achievements of human beings: a process by which children not only acquire words, but also begin to mentally represent the world.