John Bickle

The structuralist program has developed a useful metascientific resource: ontological reductive links (ORLs) between the constituents of the potential models of reduced and reducing theories. This resource was developed initially to overcome an objection to structuralist ``global'' accounts of the intertheoretic reduction relation. But it also illuminates the way that concepts at a higher level of scientific investigation (e.g., cognitive psychology) become ``structured through reduction'' to lower-level investigations (e.g., cellular/molecular neuroscience). After (briefly) explaining this structuralist background, I demonstrate how this resource illuminates an actual, emerging scientific example: the link between the psychological concept of a ``consolidation switch'' from short-term to long-term memory and the cellular/molecular mechanisms of the transition from early- to late-phases of long-term potentiation (LTP) (an important type of synaptic plasticity in mammalian hippocampus and cortex).

A number of influences have combined to make reductionism an unpopular position in recent philosophy of mind and psychology. Davidson’s Principle of the Anomalousness of the Mental, the multiple realizability arguments of Putnam, Fodor, and others, and attempts to characterize supervenience or dependency as the appropriate nonreductive relation to seek between psychological and physical kinds are the most well-known objections. And these have found their mark. Being a psychophysical reductionist nowadays, as Jaegwon Kim aptly puts it, “is a bit like being a logical positivist or a member of the Old Left—an aura of doctrinaire naiveté hangs over such a person”.

The previous decade has seen renewed critical interest in the multiple realization argument. These criticisms constitute a "second wave" of challenges to this central argument in late-20th century philosophy of mind. Unlike the first wave, which challenged the premise that multiple realization is inconsistent with reduction or type identity, this second wave challenges the truth of the multiple realization premise itself. Since psychoneural reductionism was prominent among the explicit targets of the multiple realization argument, one might think that this second wave of challenges provides important aid and comfort to reductionists. In this paper, however, I provide reasons for thinking it does not. This is not to the detriment of psychoneural reductionism because, as I also argue here, and unrecognized by the current non-reductive orthodoxy in philosophy of mind, one key argument among the first wave of criticisms of the multiple realization argument has never been adequately rejoined

  Psychoneural reduction is under attack again, only this time from a former ally: cognitive neuroscience. It has become popular to think of the brain as a complex system whose theoretically important properties emerge from dynamic, non-linear interactions between its component parts. ``Emergence'' is supposed to replace reduction: the latter is thought to be incapable of explaining the brain qua complex system. Rather than engage this issue at the level of theories of reduction versus theories of emergence, I here emphasize a role that reductionism plays – and will continue to play – even if neuroscience adopts this ``complex systems'' view. In detailed investigations into the function of complex neural circuits, certain questions can only be addressed by moving down levels and scales. This role for reduction also finds a place for approaches that dominate mainstream neuroscience, like the widespread use of experimental techniques and theories from molecular biology and biochemistry. These are difficult to reconcile with the anti-reductionist sentiments of the ``complex systems'' branch of cognitive neuroscience

Structuralism provides useful resources for advancing our understanding of the intertheoretic reduction relation and its place in the history of science. This paper begins by surveying these resources and assessing their metascientific significance. Nevertheless, important challenges remain. I close by arguing that the reductionism implicit in current scientific practice in a paradigmatic reductionistic scientific field –“molecular and cellular cognition”– is better understood on an “intervene and track” model rather than as any kind of intertheoretic relation. I illustrate my alternative model by describing briefly a recent reductionistic result from the field. It appears doubtful that any structuralist resources will illuminate this newly-recognized type of reduction-in-actual-scientific-practice

The need for representations and computations over their contents in psychological explanations is often cited as both the mark of the genuinely cognitive and a source of skepticism about the reducibility of cognitive theories to neuroscience. A generic version of this anti-reductionist argument is rejected in this paper as unsound, since (i) current thinking about associative learning emphasizes the need for cognitivist resources in theories adequate to explain even the simplest form of this phenomena (Pavlovian conditioning), and yet (ii) the most widely accepted recent theory of associative learning, which utilizes cognitivist resources, has already been reduced to a purely neurophysiological account. Psychoneural reduction of genuinely cognitivist theories is thus already an accomplished scientific fact, despite pronouncements by anti-reductionists about its conceptual impossibility or empirical implausibility. In addition, the specific form of reduction involved in this case (“combinatorial” reduction) provides a promising model for further cognitivist-to-neuroscience theory reductions

Davidson's principle of the anomalousness of the mental was instrumental in discrediting once-popular versions of mind-brain reductionism. In this essay I argue that a novel account of intertheoretic reduction, which does not require the sort of cross-theoretic bridge laws that Davidson's principle rules out, allows a version of mind-brain reductionism which is immune from Davidson's challenge. In the final section, I address a second worry about reductionism, also based on Davidson's principle, that survives this response. I argue that new reductionists should revise some significant details of the program, particularly the conception of theories, to circumvent this more potent Davidson-inspired worry

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.