AN EXPOSITION AND CRITICISM. 311 



attention is concentrated on one object, it is unavoidably withdrawn 

 from others. No mental activity therefore, which has once been 

 excited, is ever wholly lost, though the great proportion of our mentfti 

 possessions exist beyond the sphere of consciousness (II. pp. 209—218). 

 The existence of latent states of mind, while it explains the phenom- 

 ena of memory, is also proved-on independent grounds. For 



1. In external perception there is required in the object a certain 

 amount of force, less than which is incapable of affecting the senses. 

 This minimum sensibile, however, is composed of parts which separate- 

 ly are incapable of awakening sensation. Every sensation, therefore, 

 of which we are conscious, results from a combination of impressions 

 of which we are unconscious. 



2. It frequently happens that one state of consciousness follows im- 

 mediately upon another, although their connection cannot be accounted 

 for by any of the laws of association. This can be explained solely 

 by the supposition that both states of consciousness have been con- 

 nected with a state of mind which has acted as the intermediate link 

 between them without rising into consciousness. 



3. In the exercise of our acquired dexterities and habits we are 

 conscious of performing a whole series of actions without being con- 

 scious of the individual steps of the series. This in like manner can 

 be explained only by supposing that the separate volitions, which pro- 

 duce the different actions of the series, all actually take place, though 

 with such, rapidity that they are unable sepaiately to affect the con- 

 sciousness (I. pp. 349-61). 



Third Faculty — The Rej))'oductive. 



As we not only retain our knowledge out of consciousness, but can 

 bring it back into consciousness again, we must possess a faculty by 

 which it is reproduced. This reproduction may take place with or 

 without an act of will ; and in the former case it is called Reminiscence^ 

 in the latter Suggestion (II. pp. 246-7)- 



But whether voluntary or involuntary, the resuscitation of past 

 mental states is alike subject to law. The laws, in accordance with 

 which one mental state is determined to succeed another, have all their 

 ground in three subjective unities or wholes : 



(I). The unity of thoughts, differing in time and modification in a ^ 

 co-identity of subject; (2). The unity of thoughts, differing in time, 

 in a co-identity of modification; (3), The unity of thoughts, differ- 

 ing in modification, in a co-identity of time {Raid's Works, p. 912). 



