Words, Thoughts, and Theories

1. The Other Socratic Method

• The child treats the adult language as another source of information about the structure of the world, along with her own experience. While the child is inferring the structure of the outside world, she is also untangling the structure of language itself, and she may use solutions in one area as clues to solutions in the other.
• Ultimately, our motivation for watching and talking to children is the same as Socrates'. The most central questions in cognitive science are questions that only they can answer.

I: The Theory Theory

2. The Scientist as Child

• Science is cognitive almost by definition, insofar as cognition is about how minds arrive at veridical conceptions of the world.
• A cognitive view of science might provide a useful middle ground, even a bridge, between logical and sociological views of science.
• Quite typically, underlying any human cognitive activity is an abstract structure that is not at all apparent in superficial phenomenology or practice.
• From an evolutionary point of view, three of the most distinctive features of human beings are their long, protected immaturity, the plasticity of their behavior, and their ability to adapt to an extremely wide variety of environments. Equipping human children with particularly powerful and flexible cognitive devices might be an important part of this picture. Indeed, we might think of childhood as a period when many of the requirements for survival are suspended so that children can concentrate on acquiring a veridical picture of the particular physical and social world in which they find themselves.
• Once, as children, we have engaged in the theorizing necessary to specify the features of our world, most of us most of the time may simply go on to the central evolutionary business of feeding and reproducing. But, we suggest, these powerful theorizing abilities continue to allow all of us some of the time and some of us, namely professional scientists, much of the time to continue to discover more and more about the world around us.
• A characteristic lesson of the cognitive revolution is that human beings (or, for that matter, machines) can perform extremely complex feats of information processing without any phenomenology at all. It is rather characteristic of human cognition that it is largely inaccessible to conscious reflection.
• Children, no less than scientists, develop their understanding of the world in the context of a society that already has much knowledge of the world. they live in a rich social structure with much opportunity for contradiction, instruction, and the linguistic transmission of information.
• We might argue that much of the social structure of science is an attempt to replicate the privileged sociological conditions of infancy. Aside from the division of labor, the social hierarchy largely determines who will get the leisure and equipment to do cognitive work and who other scientists should listen to. The infant solves these problems without needing elaborate social arrangements.
• What happens when the theorizing mechanisms are faced with a causal problem but have no relevant evidence to operate on? What happens, we suggest, is magic, a combination of narrative, deference, and association.
• In the course of developing an account of the mind, children postulate such mental entities as perceptions, beliefs, and desires as a way of explaining ordinary human behavior.
• It is not that children are little scientists but that scientists are big children. Scientific progress is possible because scientists employ cognitive processes that are first seen in very young children.

Theories:

• Are always constructed with reference to evidence.
• Include entities and laws that are postulated or recruited from elsewhere to explain evidence.
• The entities postulated by a theory are closely, "lawfully", interrelated with one another.
• Appeal to some underlying causal structure that we think is responsible for the superficial regularities in the data.
• An accepted theory is supposed to carve nature at its joints; the theoretical entities and laws are supposed to tell you what there is and what it must do.
• A test of theoreticity is the nature of our surprise at violations of the theory. If we are committed to the theory, such violations should strike us not only as surprising but as being impossible and unbelievable in an important and strong way.
• A theory, in contrast to a mere empirical generalization, makes predictions about a wide variety of evidence, including evidence that played no role in the theory's initial construction
• The ability to produce wide-ranging predictions is perhaps the most obvious pragmatic benefit of science, and it may also be the most important evolutionary benefit of developing theorizing abilities. The evolutionary value of a system that leads to accurate and wide-ranging predictions should be obvious. In fact, making accurate predictions about the behavior of the world and your fellow organisms is the sine qua non of cognition.
• Theories produce interpretations of evidence, not simply descriptions and typologies of it. Indeed, theories strongly influence which pieces of evidence we consider salient or important. Theory-driven interpretations help to solve what computer scientists call "the frame problem". Theories provide a way of deciding which evidence is relevant to a particular problem
• What we mean by saying that we've explained something is simply that we can give an abstract, coherent, causal account of it. We might say that explanation is to cognition as orgasm is to reproduction.
• We might speculate that we were designed with a theorizing drive and that explanation is a symptom of that drive in action.
• Theories may turn out to be inconsistent with the evidence, and because of this theories change. In fact a tenet of modern epistemology is that any aspect of a theory, even the most central ones, may change.
• The initial reaction of a theory to counter-evidence may be a kind of denial. The interpretive mechanisms of the theory may treat the counter-evidence as noise, mess, not worth attending to. At a slightly later stage, the theory may develop ad hoc auxiliary hypotheses designed to account specifically for such counter-evidence. The theory gets ugly and messy instead of being beautiful and simple. The preference for beautiful theories over ugly ones plays an additional major role in theory change.
• A next step requires an alternative model to the original theory. The theory may limp along for some time under the weight of its auxiliary hypotheses if no alternative way of making progress is available. The ability to fix on this alternative is the mysterious logic of discovery.
• The new idea is not simply the olde idea applied to a new domain, but rather the earlier idea is itself modified to fit its role in the new theory. Moreover the fertility of the alternative idea may not be immediately recognized. Initially it may be applied only to the problematic cases.
• A final important dynamic feature of theory formation is a period of intense experimentation and/or observation. This period might span both the crisis of the earlier theory (when anomalous results are being produced right and left) and the first stages of the new theory (when a whole range of new predictions become available).
• In the development of the heliocentric theory of the planets:
  • Auxiliary hypotheses involving more and more complex arrangements of epicycles were initially invoked to deal with counterevidence
  • Later heliocentrism was introduced by Copernicus, but it continued to rely on epicycles as an auxiliary hypothesis.
  • Tycho Brahe's account acknowledges many of the flaws of the Ptolemaic accounts and uses the ides of heliocentrism to deal with them, but fails to accept the central idea that the earth itself goes around the sun.
  • Only with Kepler is there a really coherent heliocentric account that deals both with the anomalies and with the earlier data itself. And while, strictly speaking, experimentation on the heavenly bodies was impossible, periods of intense and detailed observation in this transitional period provided a far richer empirical base than had been available before.
• This distinctive pattern of prediction, interpretation, and explanation is among the best indicators of a theoretical structure and the best ways of distinguishing the theory theory from its developmental competitors.
• Infants show a kind of motivation and satisfaction that goes well beyond any immediate functional or social reward. Infants seem to have cognitive orgasms.
• A person's theory is a system that assigns representations to inputs just as one's perceptual system assigns representations to visual input or one's syntactic system assigns representations to phonological input.
• The representations are operated on by rules that lead to new representations; for example, the theory generates predictions. There are also distinctive functional relations between the theoretical representations and the input to them; theories predict, interpret, and explain data.
• Exactly what is the input to our theory systems?
• There is no atheoretical, evidential, "ordinary knowledge" level of representation, at least not once we get past very low level perceptual processing. All representation will be theory-laden. Even apparently "ordinary" kind of knowledge, like our knowledge that this is a jar and that is a table, or perhaps even that these are two objects and one is on top of the other, will be the result of the application of everyday theories.
• The most important and distinctive thing about theories is the fact that the very patterns of representation that occur can alter the nature of the representational system itself.
• Moreover, this system may be dynamic at yet another level. It is also possible that the very rules that restructure the relations between inputs and representations may change as a result of new input. That is, as we learn more, we also learn new ways to learn. Certainly this seems to be true in science, and it may also be true in development.
• To borrow Neurath's philosophical metaphor, the theorizing view sees knowledge as a boat that we perpetually rebuild as we sail in it. At each point in our journey there may be only a limited and constrained set of alterations we can make to the boat to keep it seaworthy. In the end, however, we may end up with not a single plan or rivet from the original structure, and the process may go on indefinitely.
• Presumably, creatures who constructed representations in different ways in childhood, who did not assume underlying causal structure, did not search for the simples explanation, did not falsify hypotheses when there was counter-evidence, and so on, were at an evolutionary disadvantage. In adulthood, such creatures were less good at predicting which berries were members of a poisonous natural kind, which kinds of minerals would make the most seductive body paint, or when their babies were old enough to be left alone without danger. In this sense nature itself guarantees that the system gets to an understanding of nature.

3. Theories, Modules, and Empirical Generalizations

• We want to argue for a kind of developmental pluralism: there are many quite different mechanisms underlying cognitive developments, and theory formation is an important one of them.

• According to modularity theories, representations of the world are not constructed from evidence in the course of development. Instead, representations are produced by innate structures, modules, or constraints that have been constructed in the course of evolution. These structures may need to be triggered, but one they are triggered, they create mandatory representations of input
• On the starting-state view, the child is innately endowed with a particular set of representations of input and rules operating on the representations. According to this view, such initial structures, while innate, would be defeasible; any part of them could be, and indeed will be, altered by new evidence. We propose that there are innate theories that are later modified and revised. The process of theory change and replacement begins at birth.
• Certainly, this type of account seems more tractable than one in which theory-like conceptual structures are constructed from scratch from a disorganized flow of experience.
• Modularity nativism, on the other hand, implies a much stronger set of claims. For Fodor, for example, modules are not only innate; they are also encapsulated and the representations that are the outcome of modules cannot be overturned by new patterns of evidence.
• At least some of the structural and functional features of theories - their abstractness, coherence, and predictive and interpretive force - can also be found in modules.
• According to the theory theory, input is evidence. It radically alters the nature of theoretical concepts.
• A theorizing mechanism is a representational system that reorganizes itself in response to input. It is an inherently developmental system. This leads to a distinctive set of developmental predictions. The theory theory predicts a succession of different theories, each replacing the earlier theory
• Modular representations do not lead to predictions through some set of inductive or deductive generalizations or through a process of theory testing, confirmation and disconfirmation. They lead to predictions because they are specifically designed by evolution to do so.

• Some theories in cognitive science have proposed that knowledge consists of empirical generalizations. "Scripts" are an example.
• Like theories, but unlike modules, empirical generalizations, scripts, narratives, and nets are defeasible.
• When we want deeper explanatory adequacy or wider predictive power, we turn from scripts to theories, even when we are talking about restaurants.
• Modules must help to provide the input to theorizing processes. On any view, there are encapsulated atheoretical processes that take us from patterns of stimulation at the retina to patterns of representation in the visual cortex.
• How far up, as it were, do these modular process go? Where is the border between modules and theories, between the periphery and the center?
• A lesson of the cognitive revolution is that phenomenology does not, in general, recapitulate epistemology. On this view, many representations that are theoretical, in the sense of being revisable and defeasible in theory-like ways, might have much of the direct, vivid phenomenology of perception.
• Empirical generalizations often seem to play a crucial role in theory change. Almost by definition, they are the kind of knowledge that provides us with counter-evidence to the predictions of the theory.
• On our view, modules, theories, and empirical generalizations are all in play literally from birth. Innate theories will assign powerful, abstract, and predictive representations to the outputs of modules. New information coming into the cognitive system will be represented in terms of these theories. Some relations among the inputs will not, however, be predicted by the theories; they will constitute empirical generalizations. Eventually, some of these kinds of inputs will lead to a revision of the theory, the modular outputs will be assigned new representations by the new theory, and so on.
• In the same way that technological advances enable or facilitate change in science, so information processing advances might enable or facilitate theory change in children.
• The most significant alternative to modularity accounts in syntactic development is not the theory theory but rather various functionalist theories that emphasize the role of social interaction in language acquisition. Assimilating all cognitive development to the model of socialization is, however, a dreadful mistake.