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Computationalism: The Very Idea

David DavenportBilkent University,

Ankara 06533 – Turkey.Email: david@bilkent.edu.tr

disclaimer(non-standard!)

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Introduction

Wealth of detail lacks solid

foundations Understand

the “big-picture” organising

principle -vocabulary

COMPUTATIONALISM

101

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Outline

Introduction What is Computation? What is Cognition? Is Computationalism correct? Issues

Meaning Symbols & Rules Representation Timing

Concluding Remarks

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Models…

Physical Replicas Answer questions Make predictions Implementation independent Observer-relative Cost, time,

difficulty of production

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Models… Abstract {computational} Answer questions,

make predictions! Map questions to answers

All equivalent

a=f(q)

a=r(s(s(t(q))))

a=u(v(q))

g=t(q)for 2 times h=s(g) g=ha=r(h)

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Implementation

Map states & seq. Find existing system Construct one anew Use digital computer

Rely on causation Program/algorithm/computation is

abstract spec. of causal system.

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What is Computation?

Answer questions, make predictions!

A function! Abstract, but physical implementation.

Program/algorithm/computation abstract spec. of causal system.

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Computation…

Targetsystem

Implementation

Abstraction

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Putnam’s Argument…

Explain & refute

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What is Computation?

About Prediction Program/algorithm/computation

abstract spec. of causal system. Concept is not vacuous! But, it is in the eye of the beholder

Interpretation State & system!

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What is Cognition?

Agents – parts of world Cognitive Agents use knowledge Prediction is the key! Models predict Choose most appropriate action

based on present situation, past experience, knowledge of effects of own actions.

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Computationalism

Can cognition be described or simulated by computations?

Different levels! Assuming

physical basis & occurs

elsewhere

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Computationalism

Is cognition literally computation?

Computation is part of cognition (the agent’s world model)

The rest, I/O, goals, matching & decision making mechanism?

Semantics? Subjective aspects…?

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Computationalism

Can the notion of computation help explain cognition?

Computation is clearly Of practical &

historic importance! Related to cognition Not vacuous!

Does lack semantics, timing & is not embedded, but…

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Meaning

Representations acquire it From other symbols?

Chinese Room Argument Foreign language dictionary

From causal links to environment? Symbol Grounding, but…

State has meaning for the agent If it has predictive value! May be wrong, unreal,

undemonstrated, etc.

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Symbols & Rules

Model viewed as formal system Symbols & rules may be

Innate or Learnt Primitive symbols

Disjunctions/Conjunctions Internal or External

Rules – logical mechanism!

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Representation

Symbolic, Connectionist,Dynamicist?

Functional accounts ofCognition & computation

Organisation/Implementation issue.

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Timing

Too quick Too slow Unstable!

Maybe time is sequence!

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Concluding Remarks Computationalism is right!

Computation, is about prediction Cognition, demands prediction

Computation - states representational

only to observer Cognition - states representational

to observer & for agent itself

(i.e. has predictive value.)

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PhysicalSystems

Cognitive

ActuallyComputingSystems

PotentiallyComputationalSystems

Classes of Systems