John Bickle

Although great progress in neuroanatomy and physiology has occurred lately, we still cannot go directly to those levels to discover the neural mechanisms of higher cognition and consciousness. But we can use neurocomputational methods based on these details to push this project forward. Here we describe vector subtraction as an operation that computes sequential paths through high-dimensional vector spaces. Vector-space interpretations of network activity patterns are a fruitful resource in recent computational neuroscience. Vector subtraction also appears to be implemented neurally in primate frontal eye field activity, which computes dimensions of saccadic eye movements. We use this apparent neural implementation as a model and construct from it a general neurocomputational account of an important type of sequential cognitive and conscious process. We defend the biological plausibility of all components of the general model and show that it yields testable anatomical and physiological predictions. We close by suggesting some interesting consequences for consciousness if our model characterizes correctly the neural mechanisms producing a common type of episode in our conscious streams.

As opposed to the dismissive attitude toward reductionism that is popular in current philosophy of mind, a “ruthless reductionism” is alive and thriving in “molecular and cellular cognition”—a field of research within cellular and molecular neuroscience, the current mainstream of the discipline. Basic experimental practices and emerging results from this field imply that two common assertions by philosophers and cognitive scientists are false: (1) that we do not know much about how the brain works, and (2) that lower-level neuroscience cannot explain cognition and complex behavior directly. These experimental practices involve intervening directly with molecular components of sub-cellular and gene expression pathways in neurons and then measuring specific behaviors. These behaviors are tracked using tests that are widely accepted by experimental psychologists to study the psychological phenomenon at issue (e.g., memory, attention, and perception). Here I illustrate these practices and their importance for explanation and reduction in current mainstream neuroscience by describing recent work on social recognition memory in mammals.

We introduce a new model of reduction inspired by Kemeny and Oppenheim’s model [Kemeny & Oppenheim 1956] and argue that this model is operative in a “ruthlessly reductive” part of current neuroscience. Kemeny and Oppenheim’s model was quickly rejected in mid-20th-century philosophy of science and replaced by models developed by Ernest Nagel and Kenneth Schaffner [Nagel 1961], [Schaffner 1967]. We think that Kemeny and Oppenheim’s model was correctly rejected, given what a “theory of reduction” was supposed to account for at that time. But their guiding insights about what constitutes scientific reduction—increases in explanatory scope and systematization—reflect actual practices of current reductionistic neuroscience. The key rehabilitative step to make their insights fit current scientific details is to restate them using resources from recent work on causal-mechanistic explanation. We begin with a scientific case study, drawn from the relatively new field of “molecular and cellular cognition”. It provides an explanation of the well-known Ebbinghaus spacing effect on learning and memory in terms of interactions between a transcriptional enhancer protein and its inhibiting phosphatase in neurons recruited into the memory trace. Next we briefly describe some popular models of reduction from mid-20th-century philosophy of science. We point out how these models fail to illuminate key features of our scientific case study. Finally we present our causal-mechanistically updated Kemeny and Oppenheim-inspired model and argue that it nicely accounts for the details of our scientific case study. We close with a remark that will hopefully undercut the surprise many may feel to learn that a long-rejected philosophical account of reduction actually is at work in one of the most prominent reductionistic endeavors in current science.

The Oxford Handbook of Philosophy and Neuroscience is a state-of-the-art collection of interdisciplinary research spanning philosophy (of science, mind, and ethics) and current neuroscience. Containing chapters written by some of the most prominent philosophers working in this area, and in some cases co-authored with neuroscientists, this volume reflects both the breadth and depth of current work in this exciting field. Topics include the nature of explanation in neuroscience; whether and how current neuroscience is reductionistic; consequences of current research on the neurobiology of learning and memory, perception and sensation, neurocomputational modeling, and neuroanatomy; the burgeoning field of neuroethics and the neurobiology of motivation that increasingly informs it; implications from neurology and clinical neuropsychology, especially in light of some bizarre symptoms involving misrepresentations of self; the extent and consequences of multiple realization in actual neuroscience; the new field of neuroeudamonia; and the neurophilosophy of subjectivity. This volume will interest philosophers working in numerous fields who wish to see how current neuroscience is being brought to bear directly on philosophical issues. It will also be of interest to neuroscientists who wish to learn how the research programs of some of their colleagues are being enriched by interaction with philosophers, and finally to those working in any interdisciplinary field who wish to see how two seemingly disparate disciplines--one traditional and humanistic, the other new and scientific--are being brought together to both disciplines' mutual benefit.

Philosophy and Neuroscience: A Ruthlessly Reductive Account is the first book-length treatment of philosophical issues and implications in current cellular and molecular neuroscience. John Bickle articulates a philosophical justification for investigating "lower level" neuroscientific research and describes a set of experimental details that have recently yielded the reduction of memory consolidation to the molecular mechanisms of long-term potentiation (LTP). These empirical details suggest answers to recent philosophical disputes over the nature and possibility of psycho-neural scientific reduction, including the multiple realization challenge, mental causation, and relations across explanatory levels. Bickle concludes by examining recent work in cellular neuroscience pertaining to features of conscious experience, including the cellular basis of working memory, the effects of explicit selective attention on single-cell activity in visual cortex, and sensory experiences induced by cortical microstimulation.

David Marr's three-level method for completely understanding a cognitive system and the importance he attaches to the computational level are so familiar as to scarcely need repeating. Fewer seem to recognize that Marr defends his famous method by criticizing the “reductionistic approach.” This sets up a more interesting relationship between Marr and reductionism than is usually acknowledged. I argue that Marr was correct in his criticism of the reductionists of his time—they were only describing, not explaining. But a careful metascientific account of reductionistic neuroscience over the past two decades reveals that Marr's criticisms no longer have force. Contemporary neuroscience now explains cognition directly, although in a fashion—causal-mechanistically—quite different than Marr recommended. So while Marr was correct to reject the reductionism of his day and offer an alternative method for genuinely explaining cognition, contemporary cognitive scientists now owe us a new defense of Marr's famous method and the advantages of its explanations over the type now pursued successfully in current reductionist neuroscience. There are familiar reasons for thinking that this debt will not be paid easily

This book precis describes the motives behind my recent attempt to bring to bear “ruthlessly reductive” results from cellular and molecular neuroscience onto issues in the philosophy of mind. Since readers of this journal will probably be most interested in results addressing features of conscious experience, I highlight these most prominently. My main challenge is that philosophers (even scientifically-inspired ones) are missing the nature and scope of reductionism in contemporary neuroscience by focusing exclusively on higher-level cognitive neuroscience, and ignoring the discipline's cell-physiological and molecular-biological core

Philosophers and psychologists seeking an accessible introduction to current neuroscience will find much value in this volume. Befitting the neuroscientific focus on sensory processes, many essays address explicitly the binding problem. Theoretical and experimental work pertaining to the “temporal synchronicity” solution is prominent. But there are also some surprising implications for current philosophical concerns, such as the intemalism/extemalism debate about representational content, epistemological realism, a “bottom-up” approach to naturalizing intentionality, Humean concerns about the self, and implications from phantom-limb phenomena. Higher-level theorists about the mind ignore results like these from current neuroscience at their own peril, at least from the point of view of discourse worthy of serious attention as the sciences of the mind/brain push forward into the 21st century

Over the past three decades, philosophy of science has grown increasingly “local.” Concerns have switched from general features of scientific practice to concepts, issues, and puzzles specific to particular disciplines. Philosophy of neuroscience is a natural result. This emerging area was also spurred by remarkable recent growth in the neurosciences. Cognitive and computational neuroscience continues to encroach upon issues traditionally addressed within the humanities, including the nature of consciousness, action, knowledge, and normativity. Empirical discoveries about brain structure and function suggest ways that “naturalistic” programs might develop in detail, beyond the abstract philosophical considerations in their favor. The literature distinguishes “philosophy of neuroscience” and “neurophilosophy.” The former concerns foundational issues within the neurosciences. The latter concerns application of neuroscientific concepts to traditional philosophical questions. Exploring various concepts of representation employed in neuroscientific theories is an example of the former. Examining implications of neurological syndromes for the concept of a unified self is an example of the latter. In this entry, we will assume this distinction and discuss examples of both.

One of the central problems in the philosophy of psychology is an updated version of the old mind-body problem: how levels of theories in the behavioral and brain sciences relate to one another. Many contemporary philosophers of mind believe that cognitive-psychological theories are not reducible to neurological theories. However, this antireductionism has not spawned a revival of dualism. Instead, most nonreductive physicalists prefer the idea of a one-way dependence of the mental on the physical.In Psychoneural Reduction, John Bickle presents a new type of reductionism, one that is stronger than one-way dependency yet sidesteps the arguments that sank classical reductionism. Although he makes some concessions to classical antireductionism, he argues for a relationship between psychology and neurobiology that shares some of the key aims, features, and consequences of classical reductionism. Parts of Bickle's "new wave" reductionism have emerged piecemeal over the past two decades; this is his first comprehensive statement and defense of it to appear