Philosophical Foundations of Neuroscience. P. M. S. Hacker
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new theories and novel conjectures that have emerged in the field of cognitive neuroscience over the last two decades. They offered us the possibility of extending the book by an extra hundred pages in order to do so.
After careful deliberation we decided to accede to the request. This introduction to the new edition is directed primarily at readers of the first edition who wish to know why we thought fit to write a second edition, and would like to attain an overview of what we have added or modified.
Four reasons moved us:
First, new technical developments in neuroscience, such as fMRI, were often highly problematic and new discoveries concerning blindsight and commisurotomy challenged previously received understanding. This called out for systematic clarification. Moreover, new cognitive neuroscientific doctrines were developed by Tononi and Dehaene and their research groups and demanded conceptual elucidation and evaluation.
In the twenty years since the first edition of this work there have been very substantial increases in the literature of cognitive neuroscience devoted to subjects of interest in the present work. This has required an updating of our discussions of the neuroscientific literature. For example, the over 500,000 papers using functional magnetic resonance imaging ( f MRI ), many of which are concerned with localization of brain function in relation to the exercise of psychological powers, have necessitated a brief description of this technique, introduced by Ogawa following Sherrington. This is given in §1.7 [§§1.7.1–1.7.2]. Recent observations that have been made on the origins of the Readiness Potential, used by Libet to support the claim that willed volitional movements are preceded by the early components of this potential, are sketched in §9.2. ‘Blindsight’ is a phenomenon, first researched in the twentieth century by Weiskrantz, which, in the first edition of Philosophical Foundations of Neuroscience, we showed to have been misinterpreted as a disconnect of a monitoring function in the brain that mediates sensation and perception. It is now thought to have a quite different explanation by reference to an alternative pathway that bypasses the visual striate cortex altogether. Commissurotomy was argued many decades ago by Sperry and Gazzaniga to give rise to ‘two minds’ in the same brain, a claim which again required conceptual clarification and criticism. Like ‘blindsight’, this too has now been challenged on neurophysiological grounds. We comment on the new observations concerning both these phenomena in chapter 17. Finally, there are theories on how the brain supports consciousness based on recent neuroscientific observations that require extensive connective conceptual analysis, such as the Integrated Information Theory of Tononi and the Global Workspace Theory of Dehaene. This analysis is provided in chapter 12.
This is a work of philosophical or conceptual clarification, so we have attempted to keep the technical aspects of neuroscience to a minimum. ( Extensive technical discussions are to be found in our 2008 book History of Cognitive Neuroscience.) But what we have introduced should help sketch the contemporary landscape of that subject, whose actual achievements need clarification.
Second, there was a misunderstanding concerning the subject of the book. Many reviewers and critics thought that the central subject of Philosophical Foundations of Neuroscience was the mereological fallacy in neuroscience, that is: the mistake of ascribing to the brain – a mere part of the human being, and to parts of the brain – such as the visual striate cortex, the frontal cortices, the amygdala and so forth, psychological, intellectual and volitional attributes which can logically be attributed only to the human being as a whole. This categorial mistake leads to flaws in reasoning, that is: to fallacies. We gave the impression to some reviewers that all 452 pages of the first edition were dedicated to displaying this mistake and refuting this fallacy. But this is to mistake a leitmotif for the opera itself. In the first edition, we dedicated a part of chapter 3 to the matter of ascribing to parts of the brain properties of the organism as a whole. In the new edition we have segregated this into an independent (chapter 3), separating it from a range of further fundamental conceptual entanglements (chapter 4). These include the subjects of self-ascription of experience, of introspection as a form of inner sense, of knowledge of the mental states, events and processes of other people, of privacy and subjectivity, of identity of experiences, of naming and describing experiences and of constitutive evidential grounds. These misunderstandings are not aspects of the mereological fallacy in neuroscience. They are severally and collectively no less important.
It is perfectly true that the mereological principle and the mereological fallacy run like a leitmotif through the book. But that is because this pervasive mistake causes misunderstandings, misinterpretations of the results of experiments and faulty design of experiments. So we could not avoid mentioning it in our conceptual investigations into the forms and structures of human faculties and their exercise. However, our general explanation is to be found in chapter 3 and is now clearly separated from other important conceptual flaws.
Third, Philosophical Foundations of Neuroscience was and is designed as a handbook for cognitive neuroscientists, a handbook to be consulted before commencing conceptualization and design of experiments on specific human faculties and their exercise. Reviewers and philosophers apart, we do not expect many of our cognitive neuroscientist readers to read through the whole book at successive sittings. For most such readers, this is a reference work, Parts II and III of which are to be consulted chapter by chapter as necessary. ( That is why we have allowed a fair amount of overlap and some repetition, so that each chapter should be reasonably self-contained.) The chapters in Part II cover the themes of sensation; perception; knowledge; memory; belief; thinking; mental imagery; perturbations, agitations and emotions; voluntary movement, voluntary, purposive and intentional action; executive control; automatic and mechanical behaviour. Part III is concerned with a battery of topics linked with consciousness, and has little to add on mereological errors. Its purpose is to shed light on a wide range of themes that preoccupy contemporary neuroscientists: on intransitive and transitive consciousness, on perceptual consciousness and consciousness of facts, on self-consciousness in its manifold forms and on qualia or the so-called qualitative character of experience.
Fourth, many neuroscientists and cognitive psychologists may be puzzled why philosophical analysis of salient concepts should have any relevance to the experimental neuroscientist. Some think that philosophy is now obsolete, that the great problems of philosophy over the last two and a half thousand years are destined to be resolved by study of the brain. Neuroscience, many believe, is solving the venerable problem of free will – showing experimentally that freedom of action is a delusion produced by the brain. Similarly, it is widely believed that the cognitive neuroscience of perception proves that perceptual qualities, such as sound and colour, do not exist in the ‘external world’, but are fictions produced by the brain, in the brain. Others demonstrate to their satisfaction that memories are stored in the brain at synaptic connections or cells – a modern variant of engrams. American neuroscientists commonly appeal to the 1890s work of William James as the still unsurpassed work of psychology and cognitive science. As we show, James’ s book The Principles of Psychology is a goldmine of conceptual confusions, from which much can be learned.
One reason for the widespread belief that philosophy is obsolete is that, with a history of more than two thousand years, philosophers are still alleged to be arguing over the same old problems that preoccupied Plato and Aristotle. But this is both an exaggeration and a misunderstanding. It is an exaggeration in as much as there are numerous philosophical questions that do not and could not appear in the works of Plato and Aristotle, such as the nature of alternative geometries, the post-Einsteinian puzzles about space-time, the differences between the voluntary and the intentional.