Matter and Consciousness

1 What Is This Book About?

1 What Is This Book About? The curiosity of Man, and the cunning of his Reason, have revealed much of what Nature held hidden. The structure of spacetime, the constitution of matter, the many forms of energy, the nature of life itself; all of these mysteries have become open books to us. To be sure, deep questions remain unanswered and revolutions await us still, but it is difficult to exaggerate the explosion in scientific understanding we humans have fashioned over the past 500 years. Despite this general advance, a central mystery remains largely a mystery: the nature of conscious intelligence. That is what this book is about. If conscious intelligence were still totally mysterious, there would be no useful book for me to write. But encouraging progress has indeed been made. The phenomena to be penetrated are now the common focus of a variety of related fields. Philosophy has been joined by psychology, artificial intelligence, neuroscience , ethology, and evolutionary theory, to name the principals. All of these sciences have made contributions to what used to be a purely philosophical debate, and all of them promise much more to come. 2 Chapter 1 This book is an introduction to the main elements of the current philosophical/scientific debate—to the major issues, to the competing theories, to the most important arguments and evidence. In the last thirty years, philosophy itself has made significant progress on the nature of mind: mainly by unraveling the nature of the mind’s self-knowledge, but also by providing a clearer conception of the possible alternative theories of mind between which we must finally choose, and by clarifying what sorts of evidence are needed if we are to make a reasoned choice between them. More important still, the empirical sciences mentioned have provided a steady flow of evidence relevant to the making of such a rational choice. Psychology has taught us some surprising things about the penetration and reliability of our introspective knowledge. (This is an important matter, since some theories of mind rely heavily on what self-conscious introspection is supposed to reveal.) The fields of cognitive psychology and artificial intelligence have produced provocative models of cognition, which, when ‘brought to life’ within a suitably programmed computer, mimic closely some of the complex activities of goaldriven intelligence. The neurosciences have begun to unravel the vast microsystem of interconnected brain cells or neurons that, in living creatures, appears to execute those activities. Ethology has given us new insights into the continuities, and discontinuities, relating human intelligence with the intelligence of other creatures . And evolutionary theory has revealed the long and intricate selective processes from which conscious intelligence has slowly emerged. The evidence is still ambiguous, however, and a choice among the relevant theories has not yet been made, so the reader of this book will have the pleasure and excitement of joining an intellectual adventure that is still very much in progress. What Is This Book About? 3 The discussion here opens with the most obvious of the questions in this area. What is the real nature of mental states and processes? In what medium do they take place, and how are they related to the physical world? With regard to the mind, these questions address what philosophers call the ontological problem. (In philosophical language, an ‘ontological question’ is just a question about what things really exist, and about what their essential nature is.) This problem is more widely known as the mind–body problem, and very probably you are already familiar with the most basic division in views here. On the one hand, there are materialist theories of mind, theories which claim that what we call mental states and processes are merely sophisticated states and processes of a complex physical system: the brain. On the other hand, there are dualist theories of mind, theories which claim that mental states and processes are not merely states and processes of a purely physical system, but constitute a distinct kind of phenomenon that is essentially nonphysical in nature. Many of us bring strong convictions to an issue such as this, and many will think that the choice between these alternatives is easy or obvious, but it is wise to keep an open mind here, whatever your convictions, at least until you have explored the lay of the land. There are at least five radically different versions of dualism, for example...