40 KNIGHT DUNLAP 



the properties of the process, or at least several of them, just as 

 when we speak of an apple we mean the total, or several, proper- 

 ties of the object. The perception of the contraction as a com- 

 plex fact may be conditioned by a reaction from the muscle over 

 an arc built up in the way described for the complex visual arc 

 above. The direct or immediate content of the homeodetic re- 

 action consciousness is, however, the muscle sensation (or sen- 

 sation complex). This sensation is the true image. Secondly, 

 the consciousness conditioned by the homeodetic reaction may 

 have for its ultimate or derivative object the object of the per- 

 ceptual consciousness conditioned by the heterodetic arc which 

 originally terminated in the muscular contractions initiating the 

 homeodetic arc in question. Another way of putting it is to 

 say that each perceptual reaction ends in a muscular contraction 

 which causes a thought-reaction, and that the object of the per- 

 ception and the indirect object of the thought are the same. 



The sidelights which further deductions throw on the whole 

 process of consciousness are of high luininosities, and I believe 

 that what they show is fully justified by observation. Upon 

 only one of these points need I touch hi the present paper: and 

 I discuss it only to overcome what may seem an important ob- 

 jection to the hypothesis as developed up to this point. The 

 thought-consciousness is not uniformly of both the direct object 

 and the indirect object, but is variable; sometimes it is predomi- 

 nantly of the direct content, sometimes of the indirect content. 

 This variability of attention as we usually designate it, is without 

 doubt due to variations in the relations of the particular arc or 

 group of arcs in question to the totality of other arcs occurring at 

 the same time, or in more accurate language, to the other parts 

 of the total arc-system. This conception of the dependence of 

 what Miinsterberg has called vividness, and Titchener has later 

 called sensory clearness, on the interrelations of arcs is not new. 

 It has been made familiar through the work of W. McDougall in 

 particular. This factor of interrelations also determines the 

 formation of particular arcs, and determines which of several 

 branches of an arc a particular reaction shall follow. 



