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c) Ubiquitous artistic forms in theatre, painting, sculpture, or cinema to name the most
obvious ones.
d) Certain patterns or behavioural acts like those involved in speech, sign or written
language.
In all these cases, A are characterised by the following properties: (i) they are
simplifications of some situation K; (ii) they aim to preserve the essential
characteristics of K; (iii) they can be processed by humans; and (iv) they are part of a
physical material. Therefore:
Definition-15: For a human H, an external representation of a situation K is an
artificial construction A characterised by the properties:
a) A is a simplification of K; and
b) A has been designed or constructed by H in order to preserve the essential
characteristics of K.41
We now face two questions. One, what are the essential characteristics of K?
Two, how does one decide that X is one of the essential characteristics of K? The
received answer to the first question is straightforward: what counts as ‘essential’
depend on the objective(s) of the representation. Within a given KR scheme this is
realised by the following two parameters:
(i) The aspects of K that H has decided to represent (technically known as the
scope of a representation); and
(ii) The amount of their detail (technically known as the grain size).
This standard analysis clarified by definition-15 is quite powerful and adequately
addresses Van Fraassen’s (2008, p. 15) query: “We confront here the general question
of how an item such as a picture can correctly represent, misrepresent, caricature,
flatter, or revile its subject.” Notice for instance that “correctly represent”,
“misrepresent” etc are all representations (as defined above) differentiated by the
parameters of scope and grain.
The second question though falls outside the standard analysis and leads one to
distinguish between thinking (definition-11) and tool-based reasoning. The latter,
although ultimately depends on human thinking and primitives, is characterized by a
system of rules which -after having been specified by H - enable anyone to draw
conclusions mechanically. Naturally, such tool-based reasoning whether it is carried
out by grammars, graph theories, or in general, mathematics- either ignores the
psychological mechanisms of thinking or identifies them with the inference
mechanisms of a particular KR scheme.42
At this point, if not earlier, one may question the significance of our second
question. So, let us be clear about it. Its significance stems from the need to
distinguish between ‘the human ability to create (systems of) external
representations’ (extRH) and the end result of that/those process(es). Finding out the
mechanisms of extRH would be a major breakthrough, studying or using its end results
(e.g., grammars and other formal systems) is useful to the extent of their applicability.
In view of the analysis in this and the previous sections, I am tempted to suggest that
an investigation of the mechanisms of extRH through the process of understanding and
its associated systems of primitives may be worth pursuing.