Browse Books

Reviewer: Jiri Zlatuska

The book presents a unified theory of the major properties of mind: reasoning, comprehension, natural language processing, and consciousness. It is devoted to the development of a scientific theory of cognition, bringing together ideas and methods of experimental psychology, linguistics, and artificial intelligence, and synthesizing them in a nontrivial way. Although the theory of mental models as a functional description of the background of basic mental processes is, first of all, a psychological theory, it may also provide a significant contribution to various branches of artificial intelligence, such as reasoning schemes, knowledge representation, or natural language understanding. The exposition of the theory of mental models is based on the doctrine of functionalism, i.e., on the development of a functionally adequate model of mental processes, and on the consideration of mental processes as effective (computable) procedures. The central idea of the book is that human beings construct mental models of the world. It is argued that the mind is essentially a model-building device that can itself be modeled on a computer. The book provides a blueprint for building such a model as well as a lot of experimental data to support the framework. In 16 chapters, the book provides a treatment of the concepts of thought, meaning, grammar, and consciousness. Chapter 1 exposes the methodological background of psychological theory expressed as an effective procedure, presents fundamental criteria for explanations, and outlines the basics of the theory of computability. The second chapter presents an outline of the doctrine of mental logic, which constitutes an orthodox view of the mechanism for making deductions, and describes problems connected with this approach. Chapter 3 introduces propositional reasoning, together with the properties appropriate to a psychological theory of reasoning. Chapter 4 presents the goals of a psychological theory of reasoning, experimental data concerning syllogistic reasoning, and fundamental theories of syllogistic reasoning. Shortcomings of the theories are demonstrated and all of the theories are shown to be inadequate in the face of the experiments. Chapter 5, How to Reason Syllogistically, describes the theory of syllogistic inference, based on the concept of mental models. The author demonstrates this theory to be a remedy for the experimental problems of the classical theories, and presents experimental results that thoroughly demonstrate the descriptional adequacy of the theory. The subsequent ten chapters refine various aspects of the properties of mind from the viewpoint of the proposed theory. Chapter 6 outlines a general theory of inference based on mental models. Chapter 7 discusses various types of mental representation and argues that at least three types of mental representation—viz., propositional representations, mental models, and images—are necessary for a plausible explanation of the experimental data. Chapter 8, which presents an exposition of various conceptions of meaning in model-theoretic semantics of natural language, introduces the concept of possible worlds and Montague's intensional logic [1]. Chapters 9 and 10 discuss psychological aspects of meaning and meaning representation. Chapter 11 outlines a procedural theory of semantics together with a description of a computer realization of this theory for simple spatial knowledge representation and inference. Mental models play the role of representative samples from the set of models satisfying an assertion, and they provide a mentally-representable counterpart to the model-theoretic concept of possible worlds. Chapter 12 deals with the relation of grammar and psychology. It presents an outline of the recent work of Peters [2], Gazdar [3], and Chomsky [4] on grammatical structures for natural language description. Chapter 13 presents a detailed overview of possible parsing techniques, discusses their performance, and derives requirements for the mental parser architecture. Mental parsing is demonstrated to be performed in parallel with semantic analysis, and computer implementation of a semantic transition network yielding the meaning of a sentence directly in terms of mental models is described. Chapter 14 discusses coherence of discourse, argues against the theory of story grammars, and explains related problems within the theory of mental models. Chapter 15 presents an account of the basic principles along which mental models are constructed. Methods of world representation are described, a set of forms of mental models for various roles and purposes is presented, processes constructing and interpreting mental models are summarized, basic sets of primitive concepts and conceptual primitives for mental models are discussed, and a typology of mental models is given. A powerful feature is the possibility of the embedding of mental models and the forming of nested mental models that allow a sound treatment of propositional attitudes within the theory. Eventually, the ways of representing a large or infinite number of entities with the help of small mental models is described. The last chapter of the book presents a discussion of the relationship between consciousness and computation. The essential role of parallelism in the mind's “operating system” is stressed; a treatment of consciousness, unconsciousness, and self-awareness within the functional theory, based exclusively on effective/computable processes, is provided; and arguments strongly defending the treatment of the mind as an automaton within a scientific theory are given. The book is accompanied by suggestions for further reading in computational theory, syntactic theory, logic, and model-theoretic semantics, in a bibliography containing more than 450 titles, and by name and subject indexes. The book is lively and lucid. Although it explores material from several disciplines, it is accessible to the expert and non-expert alike. There are few, if any, points one could criticize. One of them might be the implicit treatment of syllogisms, which, according to Aristotle, suppose the existence of As in judgments of the form all A are B. This is not explicitly mentioned until p. 90, although the judgment following an example of a difficult syllogism on p. 68 heavily depends on this supposition. This may confuse a reader who has only had a basic course in mathematical logic. In Chapter 8, although the exposition of Montague's intensional logic is made as clear and concise as possible, involvement of an alternative intensional logic (cf., e.g., [5]) could, in my opinion, suit the author's purposes even better. Moreover, an adequate treatment of propositional attitudes within that logic has been presented in [6] that somewhat weakens the case in Chapter 15 against model-theoretic treatment of propositional attitudes. Finally, in Chapter 12, I would also be interested in the author's possible treatment of the findings of [7], which may also contribute to a theory of language acquisition. All in all, this is an exciting and authoritative book that provides a deep insight into how the mind works. The author succeeds in bringing together important results from psychology, computer science, linguistics, and logic, and in synthesizing them into an original scientific treatment of mental functioning.