Online research in philosophy

Bechtel and Mundale (1999) argue that multiple realizability is not plausible. They point out that neuroscientists assume that psychological traits are realized similarly in homologous brain structures and contend that a biological aspect of the brain that is relevant to neuropsychological state individuation provides evidence against multiple realizability. I argue that Bechtel and Mundale adduce the wrong sort of evidence against multiple realizability. Homologous traits do not provide relevant evidence. It is homoplasious traits of brains that can provide evidence for or against multiple realizability.

The argument from multiple realizability is that, because quite diverse physical systems are capable of giving rise to identical psychological phenomena, mental states cannot be reduced to physical states. This influential argument depends upon a theory of reduction that has been defunct in the philosophy of science for at least fifteen years. Better theories are now available.

Multiple realizability has recently attracted renewed attention, for example Bickle, 1998; Bechtel and Mundale, 1999; Bechtel and McCauley, 1999; Heil, 1999; and Sober, 1999. Many of these writers revisit the topic of multiple realizability in order to show that some version of a mind-brain identity theory is viable. Although there is much of value in these recent explorations, they do not address the underlying intuitions that have vexed philosophers of mind since Hilary Putnam introduced the concern (1967). I argue that the standard way of construing multiple realizability is a much stronger claim than that of Putnam's intuition alone. I distinguish four interpretations of the multiple realizability intuition. Some common formulations of multiple realizability are almost certainly true, while others are not at all plausible. I argue that the plausible forms of multiple realizability do not impugn the prospects for a mind-brain Identity Theory.

We argue that by neglecting the fact that procedural memory may also have episodic qualities, and by considering only a systems approach to memory, Walker's account of consolidation of learning during subsequent sleep ignores alternative accounts of how sleep stages may be interdependent. We also question the proposition that sleep-based consolidation largely bypasses hippocampal structures.

Walker's target article proposes a refinement of the well known two-stage model of memory formation to explain the positive effects of sleep on consolidation. After a first stage in which a labile memory representation is formed, a further stabilisation of the memory trace takes place in the second stage, which is dependent on (REM) sleep. Walker has refined the latter stage into a stage in which a consolidation-based enhancement occurs. It is not completely clear what consolidation-based enhancement implies and how it can be dissociated from a stage for memory-stabilisation. A more serious consideration, however, is whether a second stage in memory consolidation that is solely dependent on sleep, is really necessary. The classical, passive, interference theory is able to explain adequately the findings related to the effects of sleep and memory, and can lead perhaps better to an understanding of the highly variable data in this field.

The progressive multistage stabilization of memory (consolidation) relies on post-acquisition neural reorganization. We hypothesize that two processes subserve procedural memory consolidation and are reflected in delayed post-acquisition performance gains: (1) synaptic consolidation, which is classical Hebbian, and (2) in some tasks, concurrently or consequently, “system consolidation,” which might in some skills be sleep-dependent. Behavioral interference may affect either type of consolidation.

b>: This article explains the concept of multiple realizability and its role in the philosophy of mind. In particular, I consider what is required for the multiple realizability of psychological kinds, the relevance of multiple realizability to the reducibility and autonomy of psychology, as well as further refinements of the concept that would prove helpful.

Matthew Walker's model overcomes the unrefined classical concept of consolidation as a unitary process. Presently still confined in its scope to selective data mainly referring to procedural motor learning, the model nonetheless provides a valuable starting point for further refinements, which would be required for a more comprehensive account of different types and aspects of human memory consolidation.

This article investigates several consequences of a recent trend in philosophy of mind to shift the relata of realization from mental state–physical state to function‐mechanism. It is shown, by applying both frameworks to the neuroscientific case study of memory consolidation, that, although this shift can be used to avoid the immediate antireductionist consequences of the traditional argument from multiple realizability, what is gained is a far more modest form of reductionism than recent philosophical accounts have intimated and neuroscientists themselves have claimed. †To contact the author, please write to: Department of Philosophy, University of Alabama at Birmingham, HB 414A, 900 13th Street South, Birmingham, AL 35294‐1260; e‐mail: jas1@uab.edu.

Multiple realizability is a key issue in debates over the nature of mind and reduction in the sciences. The subject consists of two parts:.