Reminder Definition of Computation Symbol system Symbol shapes

Reminder: Definition of Computation • Symbol system • Symbol shapes arbitrary • Symbol manipulations (algorithms) all syntactic (based on shape, not meaning) • Implementation-independent • Semantically interpretable (meaningful)

“Strong AI” (“Computationalism” or “Cognitivism” • “Mind is a computer program” (I. e. , cognition is computation) • “Brain is Irrelevant” (I. e. , computation is implementation-independent) • Turing Test is Decisive (I. e. , the T 2 -passing symbol system has a mind)

Chinese Room Argument • Suppose SS is the T 2 -passing symbol system (passes in Chinese, so has a mind, understands Chinese) • Because computation is implementationindependent, every implementation of SS understands Chinese • Searle implements SS -- but fails to understand Chinese

What went wrong? • System Reply: “Searle doesn’t understand, the system does” (but Searle is the system!) • Turing Test is at fault (T 2 perhaps, but T 3? ) • Symbol Grounding Problem (symbols and T 2 are not enough: symbol meanings must be grounded via T 3

The Symbol Grounding Problem • Chinese/Chinese Dictionary-Go-Round • Grounding symbols in T 3 (robotic) capacity • Neural nets and other nonsymbolic (analog, dynamic) functions • Hybrid symbolic/nonsymbolic systems • Categorical Perception (sensorimotor “toil” • Dictionary Grounding (symbolic “theft”)

Dennett on Robotics and Reverse -Engineering • Dennett is a behaviourist/instrumentalist • For him, mental capacities are just behavioural capacities • Hence TT capacity = mind • Reverse-engineering the mind is reverseengineering its behavioural capacities • Robotics is the way to design and test theories of mind

Critiques of connectionism • Cognition may not be just computation, but is it just connectionism either? • Pinker/Prince’s critique of Perceptron pasttense learning • Pylyshyn/Fodor’s critique of “systematicity”

Chalmers on Computation • What is computation for Chalmers? • “Reconfiguring hardware” via software • What can be reconfigured into what, via software? • Can a computer be reconfigured into a plane? • Why should thinking (cognition) differ from flying?