Online research in philosophy

This paper is about a puzzle which lies at the heart of contemporary physicalist theories of mind. On the one hand, the original motivation for physicalism was the need to explain the place of mental causation in the physical world. On the other hand, physicalists have recently come to see the explanation of mental causation as one of their major problems. But how can this be? How can it be that physicalist theories still have a problem explaining something which their physicalism was intended to explain in the first place? If physicalism is meant to be an explanation of mental causation, then why should it still face the problem of mental causation?

Since physicalism is fashionable nowadays, one should perhaps not be too surprised to find a growing number of theistic philosophers bent on combining theism with physicalism. I shall be arguing that this is an innovation we have good reason to resist. I begin by distinguishing global physicalism (physicalism about everything) from local physicalism (physicalism about human beings). I then present the theist who would be a physicalist with a challenge: Articulate a version of local physicalism that allows some minds to be purely material and others to be purely immaterial. After examining the main versions of local physicalism currently on offer, among them, type-type identity theory, supervenientism, emergentism and functionalism, I conclude that none of them can meet the challenge.

Contemporary consciousness studies, where it is not explicitly religious, is mostly physicalist. Theories of self and consciousness in classical Hindu thought can easily be seen to contribute to religious issues in consciousness studies. But it is also the case that there is much in that that can be useful within broadly physicalist parameters of study as well. The Mīmāṃsā and Nyāya schools, while having (nonphysicalist) soteriological goals for the metaphysical self, nonetheless provide theories of its relationship with consciousness that allow for interpretative strategies that can make their theories relevant to a broadly physicalist study of consciousness. Advaita Vedānta cannot be so interpreted, but its inquiry into the nature of consciousness can provide material for a fundamental critique of the project of objectifying consciousness.

This paper is about a puzzle which lies at the heart of contemporary physicalist theories of mind. On the one hand, the original motivation for physicalism was the need to explain the place of mental causation in the physical world. On the other hand, physicalists have recently come to see the explanation of mental causation as one of their major problems. But how can this be? I-low can it be that physicalist theories still have a problem explaining something which their physicalism was intended to explain in the first place? lf physicalism is meant to be an explanation of mental causation, then why should it still face the problem of mental causation? Disentagling this puzzle will cast light both on the recent mental causation debate and on physicalism itself. We can make a broad distinction between those forms of physicalism which identify mental and physical items and those which claim that there is some weaker relation of ’constitution’ between the mental and the physical. This latter view is now the orthodox version of physicalism. I shall argue that the problem of mental causation is only a problem for this orthodox physicalism, and not for identity theories. ln itself, this is not a particularly unusual claim. But I shall also argue that the real lesson of the mental causation debate is that orthodox physicalism is either unstable or unmotivated. It is unstable because (unlike the identity theories) it cannot reconcile mental causation with its other physicalist assumptions. It is unmotivated because in attempting to solve this mental causation problem, orthodox physicalism typically abandons one (or more) of the assumptions which form part of the original motivation for physicalism. To establish this, I need to explain (a) the nature of the arguments for physicalism, (b) the problem of mental causation, and (c) the standard solutions to the problem. These three tasks will form the main substance of this paper. But first I need to make some preliminary remarks about physicalism..

Physicalism is a program for building a unified system of knowledge about the world on the basis of the view that everything is a manifestation of the physical aspects of existence. Jeffrey Poland presents a systematic and comprehensive exploration of the philosophical foundations of this program. He investigates the core ideas, motivating values, and presuppositions of physicalism; the constraints upon an adequate formulation of physicalist doctrine; the epistemological and modal status, the scope, and the methodological roles of physicalist principles. He reviews and evaluates major objections to the program, and considers its significance for philosophy, science, society, and individual persons. He also examines the relations between physicalism and other philosophical positions, such as realism, empiricism, and relativism, and suggests that physicalism is compatible with a tolerant pluralism in the philosophical, cultural, and personal domains.

It is argued that perception is based on the same kinds of operations that characterize thought. However perception differs from thought in being rooted in the stimulus and predicated on a narrower range of (nonconscious) "knowledge". Other theories fail to do justice to the ambiguity inherent in the stimulus and the organization and enrichment inherent in the percept. Examples of perception are given that suggest determination by cognitive processing such as description, inference, and problem solving. One percept is often based upon another percept. The final percept is a preferred solution and adequately accounts for and is supported by the proximal stimulus or an initial percept to which the stimulus gives rise.

Norman's identification of a ventral system embodying a constructivist theory of perception is rejected in favor of an ecological theory of perception and perceptual learning. We summarize research showing that a key motivation for the ventral-constructivist connection, percept-percept coupling, confuses perceptual and post-perceptual processes.

The development of the issue of binding as fundamental to neural dynamics has made possible recent advances in the modeling of difficult problems of perception and brain function. Among them is perceptual segmentation, invariant pattern recognition and one-shot learning. Also, longer-term conceptual developments that have led to this success are reviewed.

Edelman suggests that any shape is encoded by an excitation vector with components corresponding to excitations of corresponding neuronal modules. This results in discrimination of stimuli in a shape space of low dimensionality. Similar vector encoding is present in color vision. Red-green, blue-yellow, bright and dark neurons are modules that represent a number of different color stimuli in color space of low dimensionality. Vector encoding allows effective computation of color differences and color similarities. Such a neuronal vector-encoding approach has also been applied to the perception of visual movement, line orientation, and stereopsis.

Given that the mind is the brain, as materialists insist, those who would understand the mind must understand the brain. Assuming that arrays of neural firing frequencies are highly salient aspects of brain information processing (the vector functional account), four hurdles to an understanding of the brain are identified and inspected: indeterminacy, micro-specificity, chaos, and openness.