THE ASSOCIATION OF IDEAS 41 



Returning now to our chief topic, we find that attention to the 

 direct content of thought reveals muscle sensations and only 

 muscle sensations. The derivative content is the idea, and is in 

 itself not different from a content of perceptual consciousness. 

 The idea is of course a variable thing, just as the object of per- 

 ception is variable; now this aspect being before consciousness, 

 not that aspect. The chief difference between ideal and percep- 

 tual content is that the idea is much more variable than the per- 

 cept; and this is because the system of muscular contractions is 

 exceedingly complex, and ever recurs in constantly varying forms. 

 An illustration of the extreme complexity of the image-contrac- 

 tions is found in language: a word as perceived kinaesthetically 

 is the sole direct content which occurs in many cases of thought, 

 and for the production of a single word a great number of mus- 

 cular activities are required. 



It is of course exceedingly difficult to separate completely in 

 introspection the direct content from the idea. The difficulty is 

 especially great if we do not understand what the direct content 

 really is. Hence we need not bepuzzled by the fact that the 

 direct content has been described in conventional psychology as 

 possessing the modality, and possibly other characteristics, of 

 the idea. For example, in many cases the so-called image is 

 classed as visual merely because the idea it controls is an idea 

 which is primarily visual, or of which the visual features have 

 been chiefly attended to. Under the influence of this tend- 

 ency alone, persons would be distributed in types strictly in 

 accordance with their habits of attention. But there is probably 

 another factor which enters to make the determining of types 

 difficult and variable. The images are operations of a great 

 variety of bodily muscles. The muscles of the face, eye-balls 

 and vocal organs participate in imagery to a very important 

 degree; the muscles of the arms and upper part of the trunk have 

 less to do, and the image-functions of the legs are perhaps still 

 less important. The sexual organs sustain a certain amount of 

 imaginative activity which, when it occurs, is very definite. 

 The muscles of the organs of the special senses are in many cases 

 concerned in " imagery," and there is a strong tendency in 



