Professor dr. J. J. Meyer Menno Lievers

WHAT IS THINKING? Conceptual problem? Empirical problem? What is the task of philosophy? Is philosophy a science?

Conceptual problem? Solution: conceptual analysis (Bennett & Hacker)

Empirical problem? No point in doing philosophy. Do research!

The problem Jonathan Bennett, Rationality (1964!) Honey-bees

Descartes ( ) Dualism of mind and body Extension is the essence of body Thinking is the essence of mind

Descartes on thought Thinking occurs with the aid of ideas (Language of thought…) Ideas are innate (inborn) Methodological solipsism - one can describe what a subject thinks by taking into account the thinking subject in isolation from his/her environment Epistemological internalism: a subject can only be said to know that P, iff she can justify P

Locke ( ) No innate ideas (à la connectionism…) Thinking is a mental act, not the essence of the mind Thinking requires perception

Kant ( ) Synthesis of Descartes and Locke ‘Thoughts without content are empty; intuitions without concepts are blind.’ Copernican turn: the way we perceive reality is a product of our thoughts (thus Harnad’s grounding problem…)

Frege ( ) Linguïstic idealism: the way we perceive reality is a product of our language Thoughts are linguistic

Dummett ( ) The Basic Tenet of Analytical Philosophy An account of language does not presuppose an account of thought An account of language yields an account of thought There is no other adequate means by which an account of thought may be given

Thoughts are linguistic The structure of our thoughts equals the structure of sentences of our language The normative rule we ought follow in thinking are the rules of our language Thinking obeys the rules of logic ‘What is meaning?’ becomes the central question in philosophy.

What is meaning? Meaning resides in your head (Descartes, Locke) Meaning is a relation between words and things in reality

Putnam’s Twin-earth Earth: water is H 2 O Twin-earth: water is XYZ What is the meaning of ‘water’? What do twins think about? Semantic externalism

Externalism Semantic externalism: after having been baptized reality determines whether a word has been used correctly or not Externalism in the philosophy of mind: the content of thoughts is determined by the environment of the thinker Epistemological externalism: we can attribute possession of knowledge that P to a subject whether she can justify P or not

The ontology of the mind Dualism Materialism

Advantages of dualism Free will Rationality and normativity Creativity Inner experience Qualitative aspects of perception

Objections to dualism Causal interaction between body and mind Mental causation? What is a mental substance?

Materialism Identitytheory Grandma’s neuron Pain = the firing of C-fibers Leibniz’s Law: (x)((x=y)-->(F)(Fx Fy))

Token-token materialism Multiple realisibility Supervenience Emergence

Putnam’s machine functionalism Turing machine Functional description Identity mental state determined by input, relations with other mental states, and output Antireductionism: psychology remains an autonomous science

Problems for functionalism Qualia Chinese room Inverted spectrum Absent qualia Chinese people (functional characterization of mental states too wide)

Develoments after functionalism Computational model of thoughts Language of thought hypothesis Modularity of mind Rise of subpersonal psychology

Modules Domainspecific Mandatory operation Limited central access Input systems are fast Shallow output Typical diseaseprocesses Informationally encapsulated Specific neural structure

Rise subpersonal psychology Subdoxastic states Modules Implicit knowledge

Back to meaning Theory of meaning is a theory of understanding Consequence: Philosophy of language is imbedded in the philosophy of mind Meaning is being analysed as a ‘way of thinking’

Gareth Evans Externalism Generality constraint: you can only attribute to a thinking subject possession of the concept F, if and only if he or she cannot only entertain the thought that Fa, but also that Fb Non-conceptual content

Back to ontology: eliminative materialism Scientific realism Impossibility of inter-theoretical reduction Theory-ladenness of perception Meaning-holism Folk-psychology is a false theory

Consequences for AI: 1. Symbol System Hypothesis Employ a rich, recursive compositional language to represent reality Build an adequate representation of reality within a universal symbol system Use input to construct representations of the environment in response to stimuli Process input (possibly into output) Output is a symbolic representation of adequate, suitable responses to the input

Philosophical presuppositions of the SSH Internalism Token-token materialism? Thinking is symbolmanipulation Innate representations? Methodological dualism Thinking normative/logical?

Connectionist systems

Adaptive (empirism) Thoughts are not propositional (compositional) Externalism? Normativity of thinking? Biologically real? No innate mental properties/knowledge?

AI versus Neurofilosofie Intelligence is a biological phenomenon Representation is a product of our biological constitution Biological materialism ‘Hard’ AI presupposes supervenience and that is nonsense

COURSE SET-UP MAPPING GREAT DEBATES: CAN COMPUTERS THINK? WEB-SITE:

SEVEN QUESTIONS 1. CAN COMPUTERS THINK?

SEVEN QUESTIONS 1. CAN COMPUTERS THINK? 2. CAN THE TURING-TEST DETERMINE WHETHER COMPUTERS CAN THINK?

SEVEN QUESTIONS 1. CAN COMPUTERS THINK? 2. CAN THE TURING-TEST DETERMINE WHETHER COMPUTERS CAN THINK? 3. CAN PHYSICAL SYMBOL SYSTEMS THINK?

SEVEN QUESTIONS 1. CAN COMPUTERS THINK? 2. CAN THE TURING-TEST DETERMINE WHETHER COMPUTERS CAN THINK? 3. CAN PHYSICAL SYMBOL SYSTEMS THINK? 4. CAN CHINESE ROOMS THINK?

SEVEN QUESTIONS 1. CAN COMPUTERS THINK? 2. CAN THE TURING-TEST DETERMINE WHETHER COMPUTERS CAN THINK? 3. CAN PHYSICAL SYMBOL SYSTEMS THINK? 4. CAN CHINESE ROOMS THINK?

SEVEN QUESTIONS 5’. CAN CONNECTIONIST NETWORKS THINK?

SEVEN QUESTIONS 5’. CAN CONNECTIONIST NETWORKS THINK? 5’’.CAN COMPUTERS THINK IN IMAGES?

SEVEN QUESTIONS 5’. CAN CONNECTIONIST NETWORKS THINK? 5’’.CAN COMPUTERS THINK IN IMAGES? 6. DO COMPUTERS HAVE TO BE CONSCIOUS TO THINK?

SEVEN QUESTIONS 5’. CAN CONNECTIONIST NETWORKS THINK? 5’’.CAN COMPUTERS THINK IN IMAGES? 6. DO COMPUTERS HAVE TO BE CONSCIOUS TO THINK? 7. ARE THINKING COMPUTERS MATHEMATICALLY POSSIBLE?