And this is what Michael Biggs wrote:
In support of the importance of the re-emergence of imagery in thinking we have several levels of use. The most passive use is non-integrated illustrations which simply repeat what is said in the text. This is the case with Diderot and the French Encyclopédie. Then we have Neurath who for efficiency's sake does not wish to say in words what can be better, more persuasively or more easily said in pictures. There is not necessarily an implication here that there are some things which can ONLY be said in illustrations. Then there is a functionalist argument by Lanham and Ester to the effect that visual thinking offers tools that textual thinking does not. Such an observation is more than an efficiency argument. In a similar manner, Wittgenstein contrasts the case of being persuaded by words with our inability to then argue the contrary with images. This is not to be confused with Wittgenstein's distinction between ``saying'' and ``showing'' in the Tractatus. This distinction in the Tractatus is a structural matter, where what is ``shown'' underlies what is ``said.'' What is shown is ineffable, but not because it refers to visual practice, e.g. ostensive definition. That ineffability belongs to Wittgenstein's later work which emphasises practice and in which ``mental pictures'' are unnecessary constructs. The emerging dominance of visual reasoning leads on to the idea that words such as ``proof'' can be described as ``a single picture.'' That is important, not because picturing and proof are synonymous, but because it leads us away from the temptation to think that a proof is telling us something about essences in contrast to a pictorial diagram which is a paradigm but not necessarily an essence.
The issue for electronic text is, then, that concepts are underpinned by non-linguistic practice. This has been hindered by the dominance of textual communication and is likely to be overcome by the visual opportunities of forms on the Internet which have advantages over straightforward text and text-string (e-mail) communication. The limit is a conceptual one, that we do not have a set of analytical tools for graphics which are comparable to those for text. For example, we can organise and structure texts in conventional ways based on practice, but no such corresponding uniformity of practice and hence of analysis can be applied to images. Thus Wittgenstein can express surprise in recognition of a likeness, and of the changes undergone when an image is accompanied by an expression of intention. This correspondence could be made explicit via analytical tools comparable to those available to us with text. We cannot analyse the physiognomy of pictures. There is therefore a fundamental disunity between visual knowledge and textual/linguistic knowledge.