> From: "Peacock, Kerry" <KLCP195@psy.soton.ac.uk>
> Date: Fri, 24 May 1996 13:18:33 GMT
> The fundamental difference between an image and a symbol is that an
> image actually resembles what it represents. A symbol, however, neither
> resembles nor is causally connected with what it represents. Images are
> non-arbitrary shapes, the shape of an image is a replica of the actual
> object. Images are central to the theory of analog processing, which
> suggests that two-dimensional shadows of images that are shined onto
> the retina (known as retinotopic mapping) are responsible for the
> encoding of sensory input.
An analog image need not be two-dimensional or even spatial; there are
acoustic or auditory (echoic) images, for example.
Retinotopic mapping is not from abject to retinal "shadow," but from
retinal "shadow" to higher point-for-point "shadows-of-shadows" in the
> Alternativley symbols are arbitrary shapes to which we give meaning.
What does it mean to "give" symbols meaning? We can INTERPRET arbitrary
shapes as if they meant something.
> For example the symbol - DOG - does in no way resemble a four legged
> animal which barks!
> However we give this symbol - DOG - its meaning,the symbol could just
> have easily been 0011001.
No, we call a dog by that name: We don't give the symbol a meaning; we
give the dog a name.
> Such symbols are combined to form
> conventions, which are the accepted usage and interpretation of these
They are combined ACCORDING TO conventions, the syntactic manipulation
rules determining combinations should come from what. If the rules make
sense, if they are an algorithm for something useful, then the symbols
and combinations can be interpreted in a way that make sense.
> However the way symbols are interpreted is heavily dependent upon
> context, environment, culture etc. No symbol has a fixed or inherent
> meaning. For example PLAIN has a differentr meaning depending on the
> context it is in - i.e. THE FOOD TASTES VERY PLAIN and THE SUN SHONE
> ON THE DESERTED PLAIN.
That is true, but it needn't be: Even if all symbols had one and only
one meaning, the difference between image and symbol would be the same.
> To English people the symbol CHAT means to talk, whereas the French
> take it to mean what we call a cat.
> Symbols are used in computations where the human brian if thought to
> work much like computers, manipulating arbitrary symbols in accordance
> with algorithms.
For an A you must go into greater depth into what can be done with
images and symbols; the differences between symbols and words, between
depictions and descriptions, between propositions and pantomime.
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