Notes for Ontology II: Mind-Brain Identity
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Mind-Brain (or Neural) Identity Theory: (J. J. C. Smart): contrary
to hard behaviorism, there are real mental events; however, they are not
macro-level behaviors but rather micro-level, neurological events.
Mental states and processes like sensations are simply brain states and
processes. What it means for someone to have an idea or experience
an emotion is obviously not the same as understanding that a neuron is
firing in the brain--both are intelligible in terms of their own domains
of discourse. But even though they mean something different and are
spoken of differently in our language, they both refer to the same neurological
event.
Objections:
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(Shaffer): If thoughts do not have the spatio-temporal properties or characteristics
of neurophysiological events, then they are not the same things
as electrochemical events in the brain (though they could be correlated).
When I say that I am thinking about X, I am not reporting on some neurological
event. It is thus not simply a matter of adapting our terminology
so that we can say that thoughts are identical to or refer to the same
thing as neurological events. [Reply: no doubt it would require that
we change the way we speak, but we could get used to speaking solely in
neurophysiological terms about minds and ideas.]
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Even if we recognized that mental states are correlated with brain
states, that would not prove that they are identical, and there would be
no way to falsify (and thus make scientific) the theory.
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Eliminative materialism (Churchland, early Rorty): folk-psychology
ways of speaking about minds are old-fashioned and need to be eliminated.
Because mental talk is hopelessly confused and fruitless, there is no way
to correlate mental states and brain states. Our linguistic expressions
(e.g., about pain) have meaning and truth value only in terms of how they
function in discursive networks (or "language games") that permit explanation
and prediction.
Critics of eliminative materialism point out, however, that pain
does not seem to be limited to particular language games or theories; so
eliminative materialism seems to be unable to fulfill its aim of eliminating
all mental expressions.
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Connectionism: mental events are patterned neurological connections in the brain, comparable to computer harware. Connectionism is like identity theory in that it associates mental activity with brain activity. But instead of focusing on isolated brain events, connectionism identifies mental events as the sequences or patterns of connections established in the network of brain cells (neurons).
Objection: patterns of connections (such as those made by computers) do not identify what is relevant to an issue, nor can they exhibit the common sense found in minds.
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Functionalism: any system of activities or functions that manipulate symbols according to programmed rules (i.e., "calculate") is said to have a mind. Mental activity depends on activities in the brain just as computations depend on computers. But just as the computations of a computer are not reducible to any part of the computer, so thoughts and intentions are not reducible to any material (brain) state.
Objection: the manipulation of symbols does not explain how those symbols are meaningful. That is, to understand meaning or to believe, desire, or intend something involves more than manipulating syntax and symbols. Though machines can calculate, they do not have thoughts, feelings, sensations (qualia): they are not conscious. Suggested antifunctionalist alternatives: Searle: mind is the product of intricate material connections in the brain (i.e., hardware). Chalmers: mental properties (e.g., intentionality) are not reducible to physical properties; they are simply different (though real) features of the world that are somehow related to the physical features of the world. McGinn: the problem of consciousness is a mystery we probably cannot solve.
Slides
- Slide One: Ontologies: Views of the Nature of Reality
- Dualism: all things are either physical or mental, material or immaterial
- Materialism: only matter in motion is real
- Behaviorism: minds & ideas are behaviors
- Mind-Brain (Neural Identity) Theory: minds are brains, ideas are brain processes (though "mind" and "brain" differ in meaning)
- Eliminative Materialism: mind=brain, idea=brain process; need to eliminate mental talk
- Functionalism: "mental" means manipulating symbols according to programmed rules
- Connectionism: mind is the product of neural sequencing, intricate material connections in the brain (i.e., hardware)
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Slide Two: Mind-Brain (Neural Identity) Theory
- Mental events are real: they are neuro-physiological events in the brain (mind)
- "Mind" and "brain," like "love" and "neuron firing," mean different things, but both refer to the same neurological event
- Slide Three: Objections to Mind-Brain Identity Theory
- Because thoughts do not have the same characteristics as neurological events, they are not the same.
- Even if mental states are correlated with brain states, that does not prove that they are identical. No scientific (falsifiable) theory can prove that.
- Slide Four: Eliminative (Reductive) Materialism
- We should eliminate folk-psychological talk about minds and ideas. Minds/ideas cannot be correlated with brains or neural events
- Objection: reductionism eliminates minds/ideas without explaining it simply by finding only what it looks for
- Talk of "mental events" (e.g., pain) is useful only in certain theories or language games (e.g., for explaining/predicting)
- Objection: pain is not a theoretical construct limited to particular language games
- Slide Five: Functionalism
- Any system of activities or functions that manipulate symbols according to rules (such as provided by computer software) is said to have a mind.
- Mental activity depends on activities in the brain just as programmed activities depend on computers.
- Just as the computations of a computer are not reducible to any part of the computer, so thoughts and intentions are not reducible to any material (brain) state.
- Objections: to understand meaning or to believe, desire or intend something involves more than manipulating symbols. Mental properties are either brain events or non-physical processes that are (mysteriously) related to physical properties.
- Slide Six: Connectionism
- Mental events are patterned neurological connections in the brain (=computer hardware)
- Connectionism is like identity theory, but it focuses on the sequences of connections, not isolated brain events
- Objection: patterns of connections (e.g., made by computers) do not identify what is relevant to a topic or exhibit common sense
[Additional theories NOT COVERED in this semester's course: (students
are not responsible for the following material)
C. Critical Naturalism: reality consists only of nature and natural
processes. In contrast to materialism, naturalism does not reduce
life and human activity to the physicochemical processes of the "hard sciences"
(physics, chemistry, biology), but it does say that all events (including
"emergent" or evolutionary qualities such as human activity) can be explained
fully in terms of other sciences (e.g., the social sciences: psychology,
sociology, anthropology, economics, political science). There is
no need to introduce supernatural or spiritual elements to explain existence.
Objections:
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Though the notion of emergent levels of reality may describe how consciousness
came into existence, it does not explain why there is consciousness at
all (other than to attribute the development of higher forms of life to
chance genetic mutations--which doesn't explain anything).
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If human behavior exhibits purpose and value, why can't the same be said
for the rest of nature?
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A naturalistic picture of reality is barren, devoid of the variety and
beauty we encounter in experiencing reality.
D. Idealism: Mind/Spirit and ideas are the only things that are
really real.
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Subjective idealism (Berkeley): reality is what we experience
of things, for we have no idea what it would mean to talk about reality
apart from the reality that we perceive: to be is to be perceived or to
perceive. [Objection: this seems to make reality depend on the individual
subject.]
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Objective idealism: all reality (including individual minds) is
an expression of a universal or absolute Mind. The world of changing,
material objects is merely a fleeting image of Intelligibility or Mentality
itself--what Plato calls the realm of the Forms. Mind (or Mentality
itself) is what makes the universe orderly, intelligible: in fact, Mind
is the intelligibility of the universe, the means by which it is conceivable
as some thing in the first place. Through Mind, evolution
is not merely a process of random, chance variations, but rather is a process
whose aim is revealed in the success (not simply, the survival)
of the fittest. The universe has a purpose, goal, or direction: in
short, it exhibits a teleology. Guiding the universe is a
purposive mind, God.
Objections:
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Idealists believe that, because human beings think in terms of mind and
purpose, then the universe must be that way; but that is mere anthropomorphizing
(reducing everything to human terms).
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Idealists forget that, while structure or form is part of what things are,
there is matter too; for there is no such thing as a form or structure
without it being a form or structure of some matter.
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Talk of minds or spirits is unnecessary if we can explain what we observe
in material terms alone.]