(Book review intended for Nature)
John Sloss
The Mind is one of the great mysteries of our age. The problems of how meaning, consciousness, knowledge, and free will arise in physically deterministic lumps of flesh have exercised philosophers for centuries. Almost as mystifying are the riddles of how the mind extracts information about the world, and what constitutes the nature of thought. Then there are the problems of human behaviour; why do people persist in self-destructive behaviour? Why do we like art? Why do people watch films that make them cry? We make no headway because we lack the conceptual tools to frame the problems. Like the ancient Greeks looking at the stars, we do not know how to begin to make sense of them.
Pinker admits that he does not know how the mind works, but claims to provide the conceptual scaffolding that renders these questions tractable. His thesis is that the puzzle of Mind has been downgraded from mysteries to mere problems. We may not know the solutions but we know where to look.
This work is a remarkable achievement in exposition and breadth of application. The novice has a myriad of ideas meticulously and deftly unravelled, with clarity enhanced by analogies and anecdotes. The text is also aimed at professionals in this area, to whom it presents a global view of psychology, evolutionary biology and philosophy, in addition to its main thesis. Because of its breadth of cover, some of the controversial areas are underexplored.
The book takes the form of the exposition of three theoretical stances; the Computational Theory of Mind, The Modularity of Mind and Evolutionary Psychology. These are applied to the psychology of vision, human reasoning patterns, kinship, social behaviour, the love of higher callings (e.g., art, music, humour, religion and philosophy), in an attempt to explain why events occur and how to investigate them.
The Computational Theory of Mind solves the philosophical conundrum of how mental events (e.g., beliefs and desires) march in step with and cause physical events (e.g., my avoiding a speeding car) despite there already being a complete physical causation for the latter. It postulates that, like computers, the mind is a manipulator of physical symbols, which have both representational ,i.e., standing for particular entities in the outside world, and causal properties. The symbols are acted on by the machinery of the mind in a way that is blind to its semantics, but sensitive to its syntax (or structural form). The crux of this theory is that the syntactic manipulations of a symbol respect its semantics in a truth-preserving fashion.
The Modularity of Mind states that the mind is not a single organ but a system of largely independent functional organs analogous to the organs in the body. Thus the mind is not a single general purpose intelligence, but a collection of competences each specialized for one function (e.g., stereoscopic vision). The modules are not discrete anatomical boxes, nor are they tightly sealed off from one another, communicating only through a few narrow pipelines. They are defined by the special things they do with the information available to them. The modules solve problems that are `ill-posed', they literally have no solution, by making assumptions about the nature of the world.
Lastly Evolutionary Psychology, explains the mind as a complex adaptive design in terms of Natural Selection, specifically that the mind was designed to solve the everyday problems our foraging ancestors faced. Using Evolutionary Psychology we can reverse engineer the mind - once we know what forces shaped a system we can begin to understand its components.
Pinker describes Marr's (1979) work on vision as the prime example of how the new framework is used for understanding cognition. Marr proposed that the function of the visual system was to provide a `description' of the world for all parts of the mind to exploit. Using the description as a goal, Marr was able to come up with a modular system implemented on computers that managed aspects of vision.
Pinker proposes that this technique can be used to explain and model other apparently non-adaptive behaviour. The `gambler's fallacy' occurs when an individual thinks that a roulette ball must come to rest on black after six consecutive reds. This is illogical, but the module underlying this behaviour is designed to cope with real world problems in which events have natural durations, and therefore serves an adaptive purpose.
His thesis also allows him to confront the philosophy of mind, not by solving the problems of consciousness or free will, but by declaring that our modular minds are not capable of solving these problems due to their selection for real-world problems.
There are several criticisms of Pinker's exposition:
Despite this Pinker's work is a plausible and immensely readable attempt to
locate the standpoint from which the mind should be studied.
J.Sloss is a Postgraduate Student in the Department of Cognitive and Computing Sciences, University of Sussex, Brighton, Sussex, UK.
