Philosophy of Mind

Attempts to get a grip on mind and to understand its relationship to body proliferated in the twentieth century. In the 1950s, J. J. C. Smart and U. T. Place advocated a form of identity theory. As these physicalists (or materialists) put it, consciousness is a brain process just as lightening is electrical discharge or water is H ₂O. This identity was famously challenge by the American philosopher Saul Kripke who, with his "Cartesian intuitions," argued that such an identity could only be maintained if it could be explained why it seemed to one that there could be a brain process in the absence of experience and experience in the absence of the brain process. Alternative accounts of mind were proposed. One highly influential account, functionalism, took its cue from the development of information processing and computer technology, with its important distinction between the level of implemented software and that of implementing hardware. According to functionalism, mental states are the upshot of various causal impacts from the world, and they, in their turn, typically cause certain behavior as well as other mental states. Functionalism was hailed as an advance on both behaviorism and physicalism. Unlike behaviorism, functionalism is committed to internal, causal states. Unlike physicalism, functionalism is defined as a relation among states, thus leaving open the possibility that what realizes this function may vary from individual to individual. In the words of one early exponent, the American philosopher Hilary Putnam, our brains could be made up of gray matter or Swiss cheese; what matters is the functional organization of the system. Another important proposal for the understanding of mind came from the work of another American philosopher, Donald Davidson, who aimed to reconcile the irreducibility of mind with a commitment to monism. Davidson's anomalous monism draws a distinction between type and token identity theories. Earlier identity theorists—for example, Place and Smart—aimed to identify types of mental states with types of physical states (e.g., pain with c-fiber firing); Davidson insisted that only token mental states could be identified with token physical states (e.g., my pain at noon on 3 January 2004 with a state of my brain on that date at that time). Ontological monism (all that there is, is physical) can now be combined with conceptual dualism (mental concepts are distinct from, and cannot be reduced to, physical concepts). The principle of rationality governs the mental realm, but not the physical. With this distinction Davidson hoped to reconcile our culture of materialism/physicalism with an understanding of those characteristics of mind that make us free and moral agents.

By the turn of the twentieth century, it had become clear that talk of "the mind" is too broad and that there may be issues to do with experience and sensation that are distinct from those that arise in connection with such mental states as believing, desiring, and the like (the so-called propositional attitudes). It was thought that, while functionalism, for example, might provide a plausible account of belief, it encountered real difficulties when it came to accounting for experience. This thought was reinforced with the work of the American philosopher Thomas Nagel, who pointed out that human beings—as well as other animals such as bats—enjoy conscious experiences: there is something it is like to be that organism, something it is like for that organism. Nagel labels this the "subjective character of experience" and he argues that it is hard to see how this subjectivity could be captured in an objective science of the brain. Nagel, like Descartes before him, wants to understand just how the working of the grey matter that constitutes our brain could possibly explain the way the world seems to us—explain the dazzle of fireworks or the taste of chocolate. The philosopher Colin McGinn has argued that there is a very simple explanation here, but it is not one our human minds will ever be able to comprehend. Those working in the scientific study of mind have vigorously rejected this mysterianism. One empirically oriented American philosopher, Daniel Dennett, claims to be able to reconcile our view of ourselves as rational, free, and conscious agents with a belief in the completeness of science by arguing that the former constitutes an ineliminable level of description of our behavior. Others, like the American philosophers Paul and Patricia Churchland, argue that psychological concepts such as belief, desires, and so on produce no definable brain activity and therefore these concepts should form no part of a completed science of mind.

The study of mind extends from philosophy to psychology and has expanded more recently to include neurophysiology, as well as cognitive ethology. The race is on to look ever more closely at the workings of the brain and at the behavior of all animals. On the one hand there is the age-old fascination with the idea of man as a machine, while on the other there is the hope that by understanding the fine-tuning of behavior we will find evidence that we share mentality with non-human animals.