Computation and Consciousness

Transcription

1 Computation and Consciousness Instructor: Viola Schiaffonati April,21 st 2016

2 Consciousness and the human biological system 2 Biological naturalism Consciousness as high level feature of the whole biological system Open issues Revolution in the neurosciences Way in which causation (from brain to mind) works still unknown

3 Mind-body problem 3 Biological naturalism Mental conscious states caused by underlying neurobiological processes Pain identified with certain neural firings

4 Centrality of consciousness 4 Consciousness as primary and essential feature of the mind Consciousness, intentionality, mind What exactly is consciousness? There are a number of senses of the word in ordinary speech, but there is one that is most important for philosophy and science: consciousness consists of qualitative, subjective states of feeling or sentience or awareness. These typically begin when we awake from a dreamless sleep and they go on until we fall asleep again or otherwise become unconscious. Dreams are a form of consciousness. Consciousness, in short, is a matter of the qualitative experiences that we have. To understand qualitativeness, think of the difference between drinking beer, listening to music, and thinking about your income tax. Each experience has a distinct quality. (Searle 1997)

5 Computation and consciousness (1) 5 To identify the functional features in the mental processing of information To show whether and how these features can be reproduced by using computational models Design goal Is it possible to reproduce within computational systems qualities which are usually considered as human ones?

6 Open issues 6 What do we mean exactly by consciousness? Difficult to define it univocally What is a computational model? In which sense a computational model can make sense of mental conscious processes?

7 Computation and consciousness (2) 7 Reductionist attitude until 1990 s Not possible to investigate consciousness from a scientific point of view Significant results in the neurosciences Neural correlates of consciousness

8 Consciousness and awareness 8 Chalmers 1995 Conscious experience Consciousness as experience To experience the consciousness of something Awareness Consciousness as function To have consciousness of something

9 Consciousness as experience 9 What is it like to be a bat? (Nagel 1974)

10 The subjective character of experience 10 Conscious experience is a widespread phenomenon. It occurs at many levels of animal life, though we cannot be sure of its presence in the simpler organisms, and it is very difficult to say in general what provides evidence of it. [ ] But no matter how the form may vary, the fact that an organism has conscious experience at all means, basically, that there is something it is like to be that organism. There may be further implications about the form of the experience; [ ] But fundamentally an organism has conscious mental states if and only if there is something that it is to be that organism something it is like for the organism. (Nagel 1974)

11 To be a bat 11 Concept of consciousness as subject experience Conscious experience of an organism = to feel something to be that organism It is impossible to fully describe a subjective state to who is not able to feel, experience it

12 Consciousness as a function 12 Only if we consider consciousness as a function it is possible to have computational models of consciousness Some attempts to reduce consciousness as experience to consciousness as function More similar to awareness

13 Consciousness and self-awareness 13 Self-awareness It permits to store past performed actions and processes It organizes future activities on the basis of past ones

14 Computational model 14 Three similar, but different expressions To be computable To be computational To be a computer

15 To be computable 15 X is computable X is a function from a numerable domain to a numerable codomain For each argument n of X, the corresponding value X(n) can be obtained by adopting a mechanical calculus (algorithm)

16 To be computational 16 X is computational X is a model (representing something) Model X is formulated in terms of computable functions By extension Computational is a discipline developing computational models

17 To be a computer 17 X is a computer (Copeland 1996) X is a physical system executing programs In the structure of the systems two distinct but connected components are identifiable Representation of a program Executor of a program

18 Computational models of consciousness 18 A model of consciousness is computational if can be defined in purely mechanical terms Just mechanical procedures of calculus are required to give reason of consciousness Two different interpretations of computationalism are possible Extrinsic computationalism: consciousness is computable Mental conscious activities can be simulated by specific Turing machines Collection of programs computing functions that constitute conscious thought Intrinsic computationalism: consciousness is a computer It is not sufficient to establish that consciousness is computable, but also that it has some structural properties Mental conscious activity can be modeled as a disposal executing programs

19 Descriptive and inspirational models 19 Another classification with is compatible both with extrinsic and with intrinsic computationalism Descriptive-explanatory models: they describe or explain human consciousness Inspirational models: they inspire the development of novel computer architectures

20 An inspiration 20 Making robots conscious of their mental states (McCarthy 1999)

21 References 21 Chalmers, D., Facing up to the problem of consciousness. Journal of Consciousness Studies, 2, Copeland, B.J., What is computation? Synthese, 108, Jackendoff, R., Consciousness and the computational mind. MIT Press, Cambridge, MA. McCarthy, J., Making robots conscious of their mental states. In Machine Intelligence 15, a cura di K. Furukawa, D. Michie, S. Muggleton, Oxford University Press, Oxford, Nagel, T., What is it like to be a bat? The Philosophical Review, 83, Searle, J.R., The mistery of consciousness, New York Review of Books, New York.