The brain-mind-computer trichotomy:hermeneutic approach
Peter [email protected]
Henry R. Luce ProfessorCenter for Complex Systems Studies
Kalamazoo Collegehttp://people.kzoo.edu/ perdi/
andInstitue for Particle and Nuclear Physics, Wigner Research Centre, Hungarian Academy
of Sciences, Budapesthttp://cneuro.rmki.kfki.hu/
Content
1. The brain-mind-computer trichotomy
• The brain-mind problem• The brain-computer analogy/disanalogy• The computational theory of mind
2. Hermeneutic approach
• Hermeneutics and cognitive science• Hermeneutics of the brain
3. Schizophrenia - a broken hermeneutic circle
4. Cybernetics is back!
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The brain-mind-computer trichotomy
brainmind
computer
The brain – mind problem
moisnm dualism+++
theory of mindbrain-computer
analogy/disanalogy
Hermeneutic circle
Computational
Classical cogntive science
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The Brain-Mind Problem
• monism vs. dualism
• reductionism
• emergentism
• functionalism
• downward causation
Monism:is the theory that there isonly one
fundamental kind, categoryof thing or principle.
Dualism:is the theory that the men-tal and the physical or mindand body or mind and brainare, in some sense, radicallydifferent kinds of thing.(Interactionist dualism fromDescartes to Popper andEccles)
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The Brain-Mind Problem: the philosophical approach
ReductionismComplex things can alwaysbe reduced to (explainedby) simpler or more funda-mental things.Ontological reductionism<—> monismDenial of reductionist ideasis holism
Emergentism
The properties of complexsystems are not reducibleto those of their con-stituent elements, thoughthey could not exist with-out them. While many ofthe fundamental propertiesof matter, such as mass, areheld to be merely quanti-tative and additive, emer-gent properties are said tobe qualitative and novel ornon-predictable.
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The Brain-Mind Problem
Functionalism
Functionalism is the doctrine
that what makes something a
thought, desire, pain (or any
other type of mental state)
depends not on its internal
constitution, but solely on its
function, or the role it plays,
in the cognitive system of
which it is a part. More pre-
cisely, functionalist theories
take the identity of a men-
tal state to be determined
by its causal relations to sen-
sory stimulations, other men-
tal states, and behavior.
Downward Causation
all processes at the lower level of
a hierarchy are restrained by and
act in conformity to the laws of
the higher level
Specifically: mental agents can
influence the neural functioning
”Two way causation”
The nervous system can be con-
sidered as being open to various
kinds of i nformation, and that
there would be no valid scien-
tific reason to deny the existence
of downward causation, or more
precisely, a two-way causal rela-
tionship between brain and mind
(Szentagothai)
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The brain-computer analogy/disanalogy
Cybernetics: The Founding Fathers: Warren McCulloch andNorbert Wiener
• logic-based physiological theoryof knowledge
• the brain performs logical think-ing ...
• ... which is described by logic
• therefore ...the operation of thebrain could and should be de-scribed by logic
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The brain-computer analogy/disanalogy
Cybernetics: The Founding Fathers: Warren McCulloch andNorbert Wiener
• “Behavior, Purpose and Teleol-ogy”
• Feedback control
• “Control and Communication inthe Animal and the Machine”
• Voluntary nervous system maycontrol the environment
• Theory of goal-oriented behav-ior: a new framework to under-stand the behavior of animals,humans, and computers
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John von Neumann: The Computer and the Brain
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The Computer and the Brain in broader context
• McCulloch-Pitts and the Cybernetic movement
• Self-replicating automaton: the machine and its description
• Reliable calculation with unreliable elements
• Analog vs. digital machines
• Specialized memory unit
• Language of the brain: ”Thus the outward forms of our mathematics are not absolutelyrelevant from the point of view of evaluating what the mathematical or logical languagetruly used by the central nervous system is”
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Computer-brain disanalogy (Michael Conrad)
Figure 1:
Digital computers Brainsprogrammed from outside self-organizng devicesstructurally programmable structurally non-programmablelow adaptability high adaptabilitydiscrete dynamics discrete and continuous dynamics
physical implementationirrelevant in principle depends on biological substrate
information processingat network level network and intraneuronal levels
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Computational theory of mind
Key concepts
Mental representation and Computational procedures
Thinking = Mental representations + computational procedures
more precisely: Thinking = representational structures + procedures that operate onthose structures. Analogy between computation and thinking:
data structures mental representations
+ algorithms + procedures
= running programs = thinking
Methodological consequence: study the mind by developing computer simulations of thinking
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From Cybernetics to AI and back?
While it seemed to be an analogy between Brain and Computer
+ at the elementary hardware level (binary units)
+ at the level of mathematical (quasi)-equivalence (McP vs Turing Machines)
the Organization Principles are very different
The importance of the actual biological substrate:
Synaptic organization !!
”...Eccles has shown how excitation and inhibition are expressed by changes of membrane potential..”
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Cybernetics
Second-order cybernetics
• autonomous system, role of observer, self-referential systems
• Heinz von Foerster (1911–2002)
• radical constructivism
• knowledge about the external world is obtained by preparing models on it
It is difficult to reconstruct the story, but it might be true that a set of cyberneticians,who felt the irreducible complexity of the system-observer interactions, abandoned tobuild and test formal models, and used a verbal language using metaphors. They werethe subjects of well-founded critics for not studying specific phenomena (Heylighen andJoslyn 2001)
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Cybernetics
The dissolution/dissemination of cybernetic ideas
At least four disciplines have crystallized from cybernetics
• Biological control theory
• Neural modeling
• Artificial Intelligence
• Cognitive psychology
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Hermeneutics of the brain
So far so good. But what is hermeneutics?
”A physicist friend of mine once said that in facing death, he drew some
consolation from the reflection that he would never again have to look up
the word ”hermeneutic” in the dictionary.”
(Steve Weinberg)
Hermeneutics: branch of continental (i.e. mainland European) philos-
ophy which treats the understanding and interpretation of texts.
Hermeneutic circle: definition or understanding of something em-
ploys attributes which already presuppose a definition or understanding of
that thing. The method is in strong opposition of the classical methods
of science, which does not allow such kinds of circular explanations.
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Hermeneutics of the brain
Circular and network causalitySystems with feedback connections and the systems of these connected loops can beunderstood based on the concepts of circular and network causality.Neural implementation of circular causalityFunctional macro-network for associative memory
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Schizophrenia - a broken hermeneutic circle
Understanding situations: needs hermeneutic interpretation
• logic, rule-based algorithms, and similar computational methods are too rigid to inter-pret ill-defined situations,
• hermeneutics, ”the art of interpretation” can do it.
• hermeneutics: emphasize the necessity of self-reflexive interpretation and adopts cir-cular causality
To understand other minds: i.e. to show empathy is to simulate other minds.
The neural basis of theory of mind related to mirror neurons, which is the key structureof imitation, and possibly language evolution (Michael Arbib).
A failure in interpreting self-generated action generated by the patient himself: (lackof ability to close the hermeneutic circle) can be characteristic for schizophrenic patients(Chris Firth). -> Neural basis: disconnection syndrome
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Schizophrenia - a broken hermeneutic circle
Disconnection hypotheses of schizophrenia
Geschwind’s (general) disconnection syn-dromes (1965)
The pathways implicated in the principle syndromes described by Geschwind, classifiedinto three types: sensory-limbic disconnection syndromes (dotted lines), sensory-motordisconnection syndromes (dashed lines); sensory-Wernicke’s area disconnection syndromes(solid lines).
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Schizophrenia - a broken hermeneutic circle
Disconnection hypotheses of schizophrenia
• impairments in functional macro-networks in schizophrenia was suggested
• abnormal prefronto-hippocampal connectivity?
• changes in effective connectivity: (i) intrinsic connectivity of the network, (ii) input-dependent changes
• Task related functional connectivity: during object - location associative learning
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Schizophrenia - a broken hermeneutic circle
Neural implementation of circular causality
Circular and network causality
Systems with feedback connections and the systems of these connected loops can beunderstood based on the concepts of circular and network causality.
Functional macro-network for associative memory
The glutamate - dopamine interplay (Carlsson)
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Schizophrenia - a broken hermeneutic circle
Functional Disconnectivities
• impairments in functional macro-networks in schizophrenia was suggested
• abnormal prefronto-hippocampal connectivity?
• changes in effective connectivity: (i) intrinsic connectivity of the network, (ii) input-dependent changes
• Task related functional connectivity: during object - location associative learning
Which connections are significantly impaired during schizophrenia?Quantitative estimation for the degree of impairment
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Schizophrenia - a broken hermeneutic circle
Functional Disconnectivities
Schizophrenia fMRI study: experiment and methods
x=(A+∑ j=1
Nu j B
j) x+Cu
y=λ( x ,θλ)
p(θ∣y , M )=p ( y∣θ , M ) p (θ∣M )
p( y∣M )
Task: learning of object-location associations over repeated encoding and retrieval periods
Subjects: 11 diagnosed with schizophrenia and 11 healthy controls DCM: generative model of
the BOLD signal, parameters estimated by Bayesian statistics
Model space: five areas involved, two sets defined by varying connections and the effects of conditions
Model selection: by the estimation of the Bayesian evidence
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Schizophrenia - a broken hermeneutic circle
Functional Disconnectivities
Schizophrenia fMRI study: results
Parameter level comparison: connections between PFC and HPC and HPC and IT are impairedModel comparison: top-down
information flow and the modulatory effects of conditions are less likely to be present in schizophrenia
Slow learning: differentiated from the illness by model probability distribution
Bányai M, Diwadkar V, Érdi P. Model-based dynamical analysis of functional disconnection in schizophrenia. NeuroImage 58(3): 870-877, 2011
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Broken hermeneutic circle
the role of prefrontal cortex: interpretation of the incoming signal: new associative learn-ing vs. recall
less accurate interpretation/control -> poorer performance:
if the PFC does not tell to the hippocampus when to learn and when to recall; ->poorer perfromance
the hermeneutic circle is broken
therapeutic strategy: towards a computational psycho-pharmacology: another story
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Cybernetics is back!
+ Constructivism: is a reaction against the view that knowledge and perception arethe results of sensation and maintains that(i) the nervous system, in order to be adaptive, must process available INFORMATIONactively and CONSTRUCT an internal world(ii) these process be describable in terms of algorithms
CONSTRUCTIVISM: human learning is constructed, that learners build new knowl-edge upon the foundation of previous learning. This view of learning sharply constrastswith one in which learning is the passive transformer of information from one individualto another, a view in which reception, not construction is emphasized.
Neural Constructivism: the representational features of cortex are built from the dy-namic interaction between neural growth mechanisms and environmentally derived neuralactivity.
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Cybernetics is back!
Biological systems contain their own descriptions, and therefore they need specialmethods.
[Hermeneutics: emphasize the neccessity of self-reflexive interpretation]
Dennett: not only texts, [people and artifacts], but also biological organisms can beinterpreted.
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Cybernetics is back!
Objectivity, reality, hermeneutics and interpretation
Rosen’s analysis:- this kind of objectivity is narrowly understood and based on mechanistic notions- biologists adopt a more narrow concept of objectivity: it should be independent notonly from perceptive agents, but also from the environment. - ’to explain wholes fromparts, that is ”objective”, but parts in terms of wholes, that is not’. - closed causal loopsare forbidden in the ”objective” world- the world of systems determined by linear (and only linear) causal relationships belongsto the class of ”simple systems” or mechanisms.- the alternative is not a ”subjective” world, immune to science, but a world of complexsystems, i.e., one which contains closed causal loops
Circular and network causalitySystems with feedback connections and the systems of these connected loops can beunderstood based on the concepts of circular and network causality
WHY ARE ORGANISMS DIFFERENT FROM MACHINES?
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Conclusion
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