SWIF Philosophy of Mind updated: 26 November 2002. http://www.swif.uniba.it/lei/mind/topics/perception.htm
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 Topics
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Perception, between Cognitive Sciences and Philosophy of Mind

Alessandro Dell'Anna

University of Genova (Italy)
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Perception has always been a central issue in philosophy of mind, at least since Aristotle's De Anima. Its being a bridge between the world and the subject of knowledge makes perception central but very hard to understand. In the last fifty years the debate about perception does not show signs of losing its vigour. On the contrary, an increasingly amount of new experimental and theoretical work has been produced. The main questions around which the issue of perception can be summarised are, at least, the following:

1) What's the object of perception?

2) Which is the relationship between perception and thought?

3) Is the nature of perception representational?

1) As through the whole history of western philosophy, scholars continue wondering what's the object of perception. The plain man, or naive realist, believes (or so we can suppose looking at our natural language, see Austin 1962 and Putnam 1994) that we perceive objects, properties and events without any particular effortthey seem to be perceived directly. I can see a tree in the garden, its colour and size, its cut by a woodsman. The Gestalt psychologists (Koehler 1929, Koffka 1935) claimed as well that these are the real objects of perception, the ones in which the vision scientist has to deal with. Their work enlightened some phenomenological character of these objects manipulating the observable variables: for example, the stroboscopic effect is produced by a particular functional relation between distance of the lights, velocity of movement and their sizes. During the Sixties cognitive psychology developed the different notion of perception as a process of transmission and elaboration of information (Neisser 1967). The object and his property are atomised and reconstructed by means of a flow of information in the mind, conceived as computer software. Dretske (1981) and Fodor (1983) are the philosophers who contributed significantly to the new cognitivist paradigm. Anyway it remains open if the objects of common sense play a role in the scientific enterprise or have to be eliminated. Dretske (1995b) thinks that one can be realist about the objects of perception without renouncing to be a computationalist (see Marr 1982) about its processes. Dennett (1991) is one of the principal advocates of eliminativism.

2) The dispute between Empiricism and Kantism reproduce itself today in the opposition between who thinks that perception has to be clearly distinguished from thought, and who thinks it cannot. Dretske (1981), according to the latter view, conceives of perception as an analog matrix similar to a picture in richness of information, while concepts are digitalisation of it, carrying a very specific informational content. He finds support in Marr's computational theory, and in Fodor's notion of module, according to which perception is a process whose first stages are impenetrable to concepts. We can perceive the colour of a table and its shape while mistaking it for a settle because we need not the concept "settle" to see something coloured and square. On the contrary, there are philosophers who think, like Armstrong or Dennett, that is impossible to perceive something without judging it: to see the shape of a table is to judge that it is square. Versions of this position are given by cognitive scientists such as Gregory (1966), Rock (1983) and Palmer (1999) who claim that perception always make use of something like heuristic assumptions about the possible configuration of the external world. For example, we see two men at different distance rather than a dwarf and a giant because we assume (unconsciously) that they are both men.

3) Many philosophers and cognitive scientists claim that the mind is a representational device, that is, a system capable to be in a state that is about something else (outside in the world). If I think about my brother, this thought represents (is about) my brother, if see him I represent (in a different way) him. Admittedly, the word "representation" is one of the most polysemantic in the literature, but I'll try to concentrate on this minimal characterisation. Dretske (1995a) is still one of the main proponent of such a view, claiming that the function of perception is to represent objects, properties, and facts. Contrary to Ayer (1940) or Jackson (1977) his theory does not amount to a form of idealism, because representations are not special entities (like sense data) situated between us and the world, but merely information about the world. The psychologist Gibson (1979) elaborated a notion of information very similar to this one, but he always claimed to have a direct theory of perception, in which there is no place for any mental mediation. Following Gibson, many scholars agree that the function of perception is to adapt organisms to their environment, rather than to construct a representation of it. O'Regan and Noe (2001) consider perception as an action, drawing on experiments about change blindness to demonstrate that what we see in a scene is not so detailed as we ordinarily think, because when we see we are always involved in some action.

References

- Austin J. L. 1962, Sense and Sensibilia, Oxford: Clarendon.

- Ayer A. J. 1940, Foundations of Empirical Knowledge, London: Mcmillan.

- Bozzi P. 1989, Fenomenologia sperimentale, Bologna: Il Mulino.

- Dennett D. 1991, Consciousness Explained, Boston: Little, Brown & Company.

- Dretske F. 1981, Knowledge and Flow of Information, Cambridge (Mass.): MIT Press.

- Dretske F. 1995a, Naturalizing the Mind, Cambridge (Mass.): MIT Press .

- Dretske F. 1995b, "Meaningfull Perception" in Osherson and Kosslyn (eds.), Invitation to Cognitive Science, Cambridge (Mass.): MIT Press.

- Fodor J. 1983, The Modularity of Mind, Cambridge (Mass.): MIT Press.

- Gibson J. J. 1979, The Ecological Approach to Visual Perception, Boston: Houghton Mifflin.

- Gregory R. L., 1966, The eye and the Brain, New York: McGraw-Hill Book Company.

- Jackson F. 1977, Perception: : A Representative Theory, Cambridge: Cambridge University Press.

- Koehler W. 1929, Gestalt Psychology, (1947) Rev. ed. New York: Liveright.

- Koffka K. 1935, The Principles of Gestalt Psychology, New York: Harcout Brace.

- Marr D. 1982, Vision, San Francisco: Freeman.

- Naisser U. 1967, Cognitive Psychology, New York: Appleton-Century-Crofts.

- O'Regan K. e Noe A.. 2001, "A sensorimotor account of visual perception and consciousness", BBS, 24/51.

- Palmer S. E. 1999, Vision Science, Cambridge (Mass.): MIT Press.

- Putnam H. 1994, "Sense, Nonsense and the Senses", Journal of Philosophy, n.9.

- Rock I. 1983, The Logic of Perception, Cambridge (Mass.): MIT Press.


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© 2002 Alessandro Dell'Anna