Machine Functionalism: Brains as Computing Machines

Machine functionalism, or the computational theory of mind, holds that the brain is a computational machine analogous to a computer. The authors argue that this view is flawed: computers are inaccurate models for brain states, and consciousness cannot be generated through mechanical means. They contend that while mechanical metaphors for the brain are common in everyday language and science fiction, machine functionalism faces problems including dispositional versus occurrent states, determining identical brain states across individuals, inverted qualia, and the finiteness of machine tables. The gap between syntax and semantics shows that symbol manipulation is insufficient for consciousness. The authors propose that a good theory of mind must allow multiple realizability.

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Abstract

Machine functionalism, or, the computational theory of mind, states that the inner workings of the brain are akin to the information processing of a computer. There are numerous faults with this view. Not only are computers inaccurate models for brain states, but also consciousness--as understood as generating appropriate (behavior) outputs to corresponding inputs--can’t be generated through mechanical means. In everyday language, the functions of the brain are commonly described using mecanical terminology. For instance a friend might say that “the wheels are turning slowly” in the morning before her first cup of coffee, or after hours of mental labor, she’s starting to “run out of steam.” How we apply mechanical based metaphors to the brain demonstrate how we think about it--as a machine. To be more specific, we tend to think of the brain as type of organic computer. Likewise, one of the most common themes in science fiction is that of the self-aware computer with individual personality traits. For instance, C-3po and R2-D2 in Star Wars, Marvin the ‘paranoid android’ from Hitchhiker’s Guide to the Galaxy, and Data from Star Trek: The Next Generation. These androids/robots have human characteristics and we might say they have consciousness. But these are fictional machines with emotions and thoughts modeled after humans rather than based in our current technological capabilities. It raises the question: At what point do we say that a mess of wiring and electricity--that collectively performs human-like actions-acquires consciousness? What constitutes consciousness, and can a computer program produce it? Machine functionalism, (a branch of functionalism) theorizes that computers are not just a useful metaphor is describing brain functions and mental states; brains are computational machines. Machine functionalism/ computational theory of mind states that the brain is a computer, but how viable is this theory? Machine functionalism attempts to solve problems that plagued preceding theories of mind (such as physicalism and behaviorism), but it runs into its own issues concerning: dispositional and occurent states, determining if two individuals are in the same brain Res Cogitans (2013) 4 Walker | 28 2155-4838 | commons.pacificu.edu/rescogitans state, the problem of inverted qualia, and the finiteness of machine tables. Finally, the understanding gap between syntax and semantics demonstrates that symbol manipulation is not an adequate requirement for consciousness. Intuitions Guiding Functionalism What is a brain state? What constitutes consciousness? How are the body and mind related? Starting with Descartes, modern philosophers have tried to tackle these questions. Most philosophers no longer take Cartesian dualism seriously as an adequate theory of mind. While it supports religious beliefs and the idea of a ‘soul’ (that is related to but not physically bound to the body) most modern philosophers think this is improbable. There’s no adequate explanation for how mind can affect matter. Physicalist theories claim that pains and other states are simply their physical manifestations (such as pain=c-fiber firing) fall short as well. By classifying pain exclusively as C-fiber firings, it excludes other organisms that have a different biological makeup than humans but in all other respects appear to feel pain. A good theory of mind ought to have multiple relizability, or, recognition that similar mental states are realizable in different beings. Biological similarity to homo sapiens is not a requirement in determining if a being has mental states. Logical behaviorism falls short as well. A behavioral disposition to act a certain way is in no way synonymous with the actual brain state. For instance, an individual in pain who lives in a society that has conditioned people to control their feelings, it likely to suppress the desire to say “ouch.” Someone in a more expressive society who experiences pain will definitely have some verbal outburst. Functionalism attempts to overcome these problems with physicalist and behaviorist theories.