THE PICTURE AND THE TEXT 271 



ten of, some other phase of the reader's understanding must be appealed 

 to than that of visual imagination. 



If the elementary content of subjective reality be unpicturable, much 

 less can its abstract aspects be rendered in spatial forms and relations. 

 Thus scientific and logical analysis, explanation and philosophical re- 

 flection, and the whole literature of appreciation are debarred by the 

 nature of their subject-matter from direct appeal through illustration. 

 Works on logic and metaphysics — proverbially hard thinking — are ren- 

 dered more unrelievedly so by the pages of close-packed type which fol- 

 low one another in unbroken succession from beginning to end of the 

 book. Yet it is just in such fields as this that illustration is most 

 needed. Discussion of concrete things is readily apprehended by the 

 ordinary mind, for it finds little difficulty in representing its substance 

 in imagination ; but to follow a process of abstract thought for any con- 

 tinuous period necessitates a more sustained act of attention and a mind 

 disciplined by reflection. To make them generally comprehensible such 

 abstract works imperatively demand illustration; and since a pictorial 

 commentary is out of the question exposition must proceed by an ex- 

 emplification of the concept or law to which the term illustration in its 

 wider sense is of course commonly extended. 



Pure science labors under the same difficulty as logic and meta- 

 physics. The work of reflective thought, in all its forms alike, is to 

 extract from a multitude of vivid but confusing facts some common type 

 or law to which they conform, and the elaboration of norms and princi- 

 ples in this field is found by the average mind hardly less repellant than 

 in philosophy itself. The process is laborious; it is insecure; it is un- 

 substantial. Works on pure science are not read as are those on experi- 

 mental science and natural history, because their abstractness makes 

 them more difficult ; and the writer, especially if he appeal to a technical 

 class of readers, feels that his concern is primarily in making clear the 

 theory he is developing, together with its evidence — not in illustrating 

 each aspect of it by concrete examples. 



The limits of illustration and the function it logically performs thus 

 involve a certain contradiction. Its availability and its desirability stand 

 in inverse relations. Where it is least needed — that is, when the concrete 

 things of the sensible world are dealt with, it is entirely feasible to intro- 

 duce it; but where it is most needed — in facilitating apprehension of 

 abstract conceptions, its use is practically impossible. There is therefore 

 to be expected a surfeit of pictures in the one case and a dearth, if not a 

 complete absence, of them in the other. 



Within the field where pictorial illustration offers itself as an adjunct 

 to literary treatment the further question arises of the relation which 

 text and picture logically bear to one another, and the specific service 

 which illustration renders to the reader. It may be assumed that the 

 function is thus specific, and that text and picture theoretically form 



