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Re: Suggested issues that may be addressed in next version of guidelines

From: Jason White <jasonw@ariel.ucs.unimelb.edu.au>
Date: Sat, 7 Aug 1999 15:29:35 +1000 (EST)
To: Web Content Accessibility Guidelines <w3c-wai-gl@w3.org>
Message-ID: <Pine.SOL.4.10.9908071501030.570-100000@ariel.ucs.unimelb.edu.au>
The one phrase in Charles' contribution to which I take exception is
"non-text equivalents". As Gregg has persuasively argued on several
occasions, it is not feasible to propose the inclusion of "non-text
equivalents" of textual content, except in cases where the concepts being
conveyed are sufficiently simple and every-day to permit a clear and
widely recognisable visual representation. One needs to think, rather, in
terms of visual supplements that clarify the meaning of textual material,
for example in the manner that a chart or graph can be used to summarise a
data table, or in which an image can identify the subject of a newspaper
article, or in which layout can convey the structure of a document. The
central misconception inherent in the expression "non-text equivalent" is
the implication that it is possible to represent complex concepts
non-linguistically--that is to say, without having ultimate recourse to

It should also be remembered that there are fields of knowledge which are
not amenable to visual (or more generally, non-linguistic) depiction. To
take an extreme example, it has been argued that one of the principal
reasons for introducing rigorous proofs into mathematical analysis during
the nineteenth century was precisely the impossibility of constructing
graphs that could represent the functions then under consideration. Hence,
"geometric intuitions" could no longer serve as an adequate basis of
mathematical reasoning in the calculus.

Other fields, in linguistics, philosophy and the social sciences could
readily be cited to show that there are contexts in which visual aids,
even if not entirely infeasible, would fail completely to convey the
meaning of the text and could not therefore be characterised as
equivalent thereto. Of course, the same observation holds true in respect
of certain auditory and visual presentations (for example, visual art and
music, respectively); however it remains possible to explain the over-all
effect, purpose or style of the artwork to a person who possesses the
requisite vocabulary and concepts, through a description, which, however,
can not do justice to the complexity and uniqueness of the artistic
production itself. My argument is simply that attempting to convey complex
thoughts non-linguistically is an even more problematic undertaking and
generally assumes the prior acquisition, on the part of the recipient, of
concepts which can only be developed in and through language. The more
complex and specialised the discipline, the more obvious this problem
Received on Saturday, 7 August 1999 01:29:46 UTC

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