Before the age of printing, pictures and diagrams played only a limited role. ... The Romans used simple pictures, called emblems, to help them overcome the inherent visual deficiency of their scripts: they recalled specific parts of a text by remembering the particular emblem placed against it in the margin. In early medieval manuscripts illustrations helped readers to find the part of the text they were looking for. Applied in this manner, pictures had a merely auxiliary function; and even that was lost with the introduction of word-separation. As Saenger points out, this invention gave written Latin an ideographic value without sacrificing the inherent pedagogic advantages of a phonetic alphabet. Pictures now ceased to be needed as visual aids. And prior to printing they could not become aids to the communication of knowledge. Since they were inevitably distorted in the copying process, information could not be preserved by them. With the advent of printing this changed. But even then, texts could be manipulated with much greater ease, both by the author and especially by the printer, than could pictures. ... Illustrations played, on the whole, a subordinate role; and pictures as vehicles of thinking played almost no role at all. Sometimes this was felt to be a possible loss. Thus Bacon wrote: ``Aristotle saith well, `Words are the images of cogitations, and letters are the images of words.' But yet it is not of necessity that cogitations be expressed by the medium of words. For whatsoever is capable of sufficient differences, and those perceptible by the sense, is in nature competent to express cogitations.''
This is the issue Richard Lanham today confronts when he says that scholarly argument should use images ``to think through, conceptualize, problems rather than simply to illustrate solutions arrived at through other means;'' or the issue Michael Ester addresses when he speaks about ``arrangements of images as a way to think.'' The Lanham reference is to the perspectives opened up by the possibility of manipulating images on the screen. But already in the late age of print the programme of a better integration of text and images appeared as a conceivable aim, say, to Otto Neurath. ``Frequently it is very hard,'' he wrote, ``to say in words what is clear straight away to the eye. It is unnecessary to say in words what we are able to make clear by pictures.'' Neurath was working towards an ``International System of Typographic Picture Education,'' abbreviated as isotype, an interdependent and interconnected system of images, to be used together with word languages, yet having a visual logic of its own. Isotype would be two-dimensional, using distinctive conventions, shapes, colours, and so on. Neurath particularly stressed that the elaboration of this picture language was meant to serve a broader aim, that of establishing an international encyclopaedia of common, united knowledge - the ``work of our time,'' he said - and in this connection he specifically referred to the French Encyclopaedia which ``gave a great amount of material and a great number of pictures, but there was only a loose connection between them.''