310 SIR WILLIAM Hamilton's philosophy : 



we are conscious, is admitted even by those philosophers who refuse 

 to recognise the fact in their systems (I. pp. 289 — 292 ; Reid's Worhs, 

 pp. 747 — 8) ; still the testimony of consciousness in this instance has 

 been rejected, and every alternative, which could possibly be suggested 

 to explain perception without admitting it to be an immediate know- 

 ledge of a nonego, has been actually maintained by one philosopher or 

 another (I., pp. 285—299; Reid's WorJcs, pp. 816—9). The 

 grounds, however, on which the testimony of consciousness is in this 

 case rejected, are wholly incompetent, as indeed such rejection in any 

 case must be suicidal to the philosophical system which is guilty of it 

 (I. pp. 116 — 133) ; and we are consequently forced to admit as an 

 ultimate and therefore inexplicable fact, that the knowledge of the 

 external world is equally immediate with that of the internal. 



§ 2. Self-consciousness. 



With regard to this form of the Presentative Faculty all the most 

 important questions have already been discussed in connection with 

 consciousness in general (II., pp. 185—204). 



Second Faculty — The Conservative. 



As the knowledge we acquire is not immediately lost, we must 

 possess a^ faculty, or rather a capacity, by which it is retained or con- 

 served; and it is this power which, in ordinary language, is most 

 prominently expressed by the word Memory. The fact of retention 

 various attempts have been made to account for by physiological and 

 other hypotheses'; but it is most easily explained by the self-activity 

 of the mind. For knowledge is acquired not by mere passive impres- 

 sions on the mind, but by the mind spontaneously exerting its own 

 power. Every act of knowledge is therefore an energy of the self- 

 active power of a subject one and indivisible ; and consequently a part 

 of the ego would require to be detached or annihilated, if a cognition 

 once existent were again extinguished. Hence the most difficult 

 problem is not how a mental activity endures, but how it ever vanishes. 

 This problem is solved by the consideration that, though a mental 

 activity ceases to affect our consciousness, it does not on that account 

 cease to exist. The mind possesses a certain amount of force which 

 must be distributed in various degrees among its various activities. 

 Of these the newer and fresher must necessarily be more -vivid than 

 the older ; and consequently as the former crowd in upon the latter, 

 these must fade into various degrees of obscurity just as, when our 



