ELIMINATIVE MATERIALISM

Problems in Consciousness III

Eliminative Materialism

…(or eliminativism) is the radical claim that our ordinary, common-sense understanding of the mind is deeply wrong and that some or all of the mental states posited by common-sense do not actually exist.

(Stanford Encyclopedia of Philosophy)

Eliminative Materialism

Mental states are causally irrelevant; Beliefs, desires, interests, etc. (if they exist at all) are at best ―epiphenomenal‖ – that is they are side or after-effects of neural events

Brain states cause conscious behavior.

=> if we want to understand consciousness, we should give up studying mental states and put all our efforts into studying neurophysics.

Paul Churchland & Eliminative Materialism

―The magnitude of the conceptual revolution her suggested should not be minimized; it would be enormous. And the benefits to humanity might be equally great. If each of us possessed an accurate neuroscientificunderstanding of …the varieties and causes of mental illness, the factors involved in learning, the neural basis of emotions, intelligence, and socialization, then the sum total of human misery might be much reduced.‖ (p.507)

Patricia Smith Churchland: 3 Core Claims

Hypothesis 1: Mental activity is brain activity. It is susceptible to scientific methods of investigation.

Hypothesis 2: Neuroscience needs cognitive science to know what phenomena need to be explained. To understand the scope of the capacity you want to explain—such as sleep, temperature discrimination, or skill learning—it is insufficient to simply rely on folk wisdom and introspection. Psychophysics, and experimental psychology generally, are necessary accurately to characterize the organism’s behavioral repertoire and to discover the composition, scope, and limits of the various mental capacities.

Hypothesis 3: It is necessary to understand the brain, and to understand it at many levels of organization, in order to understand the nature of the mind.

What is ―Folk Psychology‖

―Folk psychology‖ is also called the ―belief-desire thesis‖ and is based on the idea that we can explain conscious behavior with reference to beliefs, desires, interests, thoughts, ideas, etc. It is associated with ―the will.‖

For example, when asked why one came to class today, one might answer because you desired a good grade and believed that if you came to class today that action will contribute to getting that which you desired.

Churchland’s metaphor:

Folk Medicine is to Modern Medicine

Churchland’s metaphor:

As Folk Psychology is to Modern Neurophysics

Problems with Folk Psychology:

Folk psychology is based on subjective reports of mental states which are essentially meaningless – a form of a private language – with no verifiable object of reference.

Folk psychology is based on anecdotal evidence – just as is folk medicine. Successes are largely accidents rather than the product of a clear understanding of the underlying processes.

Folk psychology has encountered ―widespread explanatory, predictive and manipulative failures. So much of what is central and familiar to us remains a complete mystery from within folk psychology.” (p.508)

Folk psychology cannot explain the ―many and perplexing behavioral and cognitive deficits suffered by people with damaged brains” such as why we need sleep and how we learn. (p.508)

An Example: Ventromedial Frontal Damage & The Bechara/Damasios Card Game

―Antoine Bechara, working with the Damasios, developed a particularly revealing test. In this test, a subject is presented with four decks of cards, and told that his task is to make as much profit as possible, given an initial loan of money. Subjects are told to turn over cards, one at a time, from any of the four decks. They are not told how many cards can be played (a series of 100) or what the payoffs are from any deck. One has to discover everything by trial and error. After turning over each card, the subjects are rewarded with an amount of money, and on some cards, they may also be penalized and be required to pay out money. Behind the scenes, the experimenter designates two decks, C and D, to be low-paying ($50) and to contain some moderate penalty cards; two other decks, A and B, pay large amounts ($100) but contain very high penalty cards. Things are rigged so that players incur a net loss if they play mostly A and B, but do well if they play mostly C and D decks. Subjects cannot calculate exactly losses and gains because there is too much mentally to keep track of. Instead, subjects must generate a sense of what strategy will work to their advantage.‖

An Example: Ventromedial Frontal Damage & The Bechara /Damasios Card Game

―During the game, normal controls come fairly quickly to stick mainly with low-paying, low-penalty decks (C and D) and make a profit. What is striking is that subjects such as EVR (ventromedialfrontal damage), tend to end with a loss because they choose mainly high-paying decks despite the profit-eating penalty cards. Subjects with brain damage to regions other than ventromedial behave like controls. As Bechara et al. note, even after repeated testing on the task as long after as a month or as short after as twenty-four hours, EVR continued to play heavily the losing decks. When queried at the trial end, he verbally reports that A and B are losing decks. To put it rather paradoxically, rationally EVR does indeed know what the best long-run strategy is, but in exercising choice in actual action, he goes for short run gain, incurring long run loss.‖

Feeling Reasons, Patricia Smith Churchland, Philosophy Department and Salk Institute, UCSD, La Jolla California

The Goal: A completed neuroscience

Paul and Patricia Churchland…

http://www.youtube.com/watch?v=LpJSeLY8cWs&feature=related

Why is Folk Psychology incompatible with Neuropsychology?

Folk psychology maintains that mental states cause behavior and are essential to understanding consciousness.

Neuropsychology maintains that mental states are epiphenomenal (side or after effects caused by brain states) thus are causally irrelevant and that brain states cause behavior.

Paul Churchland on Demons and Diseases:

Folk psychology is compared to demonology and the elimination of it in light of advances in modern neurophysics: we do not translate or account for the demons once we understand the true causes of the disease: In a similar fashion, once we have a completed neuroscience we will no longer need to translate or account for mental states in causal explanations.

An example: once, epileptic seizures were thought to be caused by demon possession. However, we now understand them as abnormal movement or behavior due to unusual electrical activity in the brain. We do not need to account for or translate the demons in order to explain the causes of these seizures. ―Demon-talk‖ just disappears or is eliminated, under the more complete explanation provided by modern neurophysics.

Patricia Churchland - On Mental States

If We Get an Explanatory Reduction of Mental Life in Terms of Brain Activity, Should We Expect Our Mental Life to Go Away?

―This worry is based on misinformation concerning what reductions in science do and do not entail. The short answer to the question, therefore, is ‘‘No.’’ Pains will not cease to be real just because we understand the neurobiology of pain. That is, a reductive explanation of a macrophenomenon in terms of the dynamics of its microstructural features does not mean that the macrophenomenon is not real or is scientifically disreputable or is somehow explanatorily unworthy or redundant.‖

Patricia Smith Churchland, Brain Wise, Studies in Neurophilosophy, 2002, Massachusetts Institute of Technology

Challenges to Eliminative Materialism:

Much of these explanations lie in the future with a completed neuroscience – the theory rests on what we will discover, not on what we actually know.

In eliminating the causal feature of mental states, eliminative materialists ignore the importance of intentionality – they focus on the question of how we act consciously but do not address what those actions mean to us or what it is like to have a certain experience or whywe do what we do.

It displays a kind of chauvinism: By restricting consciousness to organic systems with complex structures, eliminativists automatically rule out other sorts of systems that may also be conscious but are not organic.