the brain-mind-computer trichotomy: hermeneutic approachgeza.kzoo.edu/~erdi/leckek/epaic.pdf · the...

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!

– Typeset by FoilTEX – 2

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


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)


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.


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)


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


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


John von Neumann: The Computer and the Brain


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”


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


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


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..”


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)


Cybernetics

The dissolution/dissemination of cybernetic ideas

At least four disciplines have crystallized from cybernetics

• Biological control theory

• Neural modeling

• Artificial Intelligence

• Cognitive psychology


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.


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


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



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).



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



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)



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




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




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


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


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.



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.



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?


Conclusion


the brain-mind-computer trichotomy: hermeneutic approachgeza.kzoo.edu/~erdi/leckek/epaic.pdf · the...

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