Philosophical Foundations of Neuroscience. P. M. S. Hacker

Introduction to the First Edition

      Philosophical Foundations of Neuroscience presents the fruits of a cooperative project between a neuroscientist and a philosopher. It is concerned with the conceptual foundations of cognitive neuroscience – foundations constituted by the structural relationships among the psychological concepts involved in investigations into the neural underpinnings of human cognitive, affective and volitional capacities. Investigating logical relations among concepts is a philosophical task. Guiding that investigation down pathways that will illuminate brain research is a neuroscientific one. Hence our joint venture.

      If we are to understand the neural structures and dynamics that make perception, thought, memory, emotion and intentional behaviour possible, clarity about these concepts and categories is essential. Both authors, coming to this investigation from very different directions, found themselves puzzled by, and sometimes uneasy with, the use of psychological concepts in contemporary neuroscience. The puzzlement was often over what might be meant by a given neuroscientist’ s claims concerning the brain and the mind, or over why a neuroscientist thought that the experiments he had undertaken illuminated the psychological capacity being studied, or over the conceptual presuppositions of the questions asked. The unease was produced by a suspicion that in some cases concepts were misconstrued, or misapplied, or stretched beyond their defining conditions of application. And the more we probed, the more convinced we became that, despite the impressive advances in cognitive neuroscience, not all was well with the general theorizing.

      Empirical questions about the nervous system are the province of neuroscience. It is its business to establish matters of fact concerning neural structures and operations. It is the task of cognitive neuroscience to explain the neural conditions that make perceptual, cognitive, cogitative, affective and volitional functions possible. Such explanatory theories are confirmed or infirmed by experimental investigations. By contrast, conceptual questions (concerning, for example, the concepts of mind or memory, thought or imagination), the description of the logical relations between concepts (such as between the concepts of perception and sensation, or the concepts of consciousness and self-consciousness), and the examination of the structural relationships between distinct conceptual fields (such as between the psychological and the neural, or the mental and the behavioural) are the proper province of philosophy.

Conceptual questions antecede matters of truth and falsehood. They are questions concerning our forms of representation, not questions concerning the truth or falsehood of empirical statements. These forms are presupposed by true (and false) scientific statements and by correct (and incorrect) scientific theories. They determine not what is empirically true or false, but rather what does and what does not make sense. Hence conceptual questions are not amenable to scientific investigation and experimentation or to scientific theorizing. For the concepts and conceptual relationships in question are presupposed by any such investigations and theorizings. Our concern here is not with trade union demarcation lines, but with distinctions between logically different kinds of intellectual inquiry. (Methodological objections to these distinctions are examined in chapter 14 [chapter 17 in this edition].)

      Conceptual questions antecede matters of truth and falsehood. They are questions concerning our forms of representation, not questions concerning the truth or falsehood of empirical statements. These forms are presupposed by true (and false) scientific statements and by correct (and incorrect) scientific theories. They determine not what is empirically true or false, but rather what does and what does not make sense. Hence conceptual questions are not amenable to scientific investigation and experimentation or to scientific theorizing. For the concepts and conceptual relationships in question are presupposed by any such investigations and theorizings. Our concern here is not with trade union demarcation lines, but with distinctions between logically different kinds of intellectual inquiry. (Methodological objections to these distinctions are examined in chapter 14 [chapter 17 in this edition].)

      Distinguishing conceptual questions from empirical ones is of the first importance. When a conceptual question is confused with a scientific one, it is bound to appear singularly refractory. It seems in such cases as if science should be able to discover the truth of the matter under investigation by theory and experiment – yet it persistently fails to do so. That is not surprising, since conceptual questions are no more amenable to empirical methods of investigation than problems in pure mathematics are solvable by the methods of physics. Furthermore, when empirical problems are addressed without adequate conceptual clarity, misconceived questions are bound to be raised, and misdirected research is likely to ensue. For any unclarity regarding the relevant concepts will be reflected in corresponding unclarity in the questions, and hence in the design of experiments intended to answer them. And any incoherence in the grasp of the relevant conceptual structure is likely to be manifest in incoherences in the interpretation of the results of experiments.

      Cognitive neuroscience operates across the boundary between two fields, neurophysiology and psychology, the respective concepts of which are categorially dissimilar. The logical or conceptual relations between the physiological and the psychological are problematic. Numerous psychological concepts and categories of concepts are difficult to bring into sharp focus. The relations between the mind and the brain, and between the psychological and the behavioural, are bewildering. Puzzlement concerning these concepts and their articulations, and concerning these apparent ‘domains’ and their relations, has characterized neurophysiology since its inception (we shall begin our investigations in chapter 1 with a historical survey of the early development of neuroscience). In spite of the great advances in neuroscience at the beginning of the twentieth century at the hands of Charles Sherrington, the battery of conceptual questions popularly known as the mind–body or mind–brain problem remained as intractable as ever – as is evident in the flawed Cartesian views embraced by Sherrington and by such of his colleagues and protégés as Edgar Adrian, John Eccles and Wilder Penfield. Brilliant though their work unquestionably was, deep conceptual confusions remained – as we show in chapter 2. Whether the current generation of neuroscientists has successfully overcome the conceptual confusions of earlier generations, or whether it has merely replaced one conceptual entanglement by others, is the subject of our investigation in this book.

One such tangle is evident in the persistent ascription of psychological attributes to the brain. For, while Sherrington and his protégés ascribed psychological attributes to the mind (conceived as a peculiar, perhaps immaterial, substance distinct from the brain), contemporary neuroscientists tend to ascribe the same range of psychological attributes to the brain (commonly, although not uniformly, conceived to be identical with the mind). But the mind, we argue (§3.10), is neither a substance distinct from the brain nor a substance identical with the brain. And we demonstrate that ascription of psychological attributes to the brain is incoherent (chapter