38 GENERAL VIEW AND BASIS OF SCIENTIFIC RESEARCH. 



dependently of some peculiar modification of the mind ; 

 we are only conscious as we are conscious of a determinate 

 state. To be conscious we must be conscious of some par- 

 ticular perception, remembrance, imagination, or feeling ; 

 we have no general consciousness.' l Persistence of ideas 

 in consciousness is the basis of our knowledge of realities, 

 and is also to a certain extent a test of truth. 



Consciousness enables us to define many things, but 

 not itself. What is consciousness ? is about the most 

 difficult of all questions for man to answer, because it is 

 asking self what is self, and the answer given can only be a 

 repetition consciousness is consciousness. Consciousness 

 appears to be a power of perceiving mental changes, 

 whether resulting from sensation or volition ; and arises 

 from a sufficiently strong and rapid nervous or mental 

 change. It includes both sensation and perception, and 

 the total consciousness in both these forms constitutes the 

 human I or Ego. Consciousness therefore differs in kind : 

 there is physical, or that of sense ; and mental, or that of 

 mind and the latter is the more complex. Mental con- 

 sciousness is not mind, nor co-extensive with it ; but only 

 a variable accompaniment of it. As there may be phy- 

 sical activity without physical consciousness, so may there 

 be mental activity without mental consciousness, but not 

 the reverse we often catch ourselves thinking. There is 

 no abstract consciousness. Consciousness differs also in 

 degree, from that which accompanies feeble sensations and 

 ideas to that concomitant with the most excited action 

 of all our senses and mental powers. The consciousness 

 attending one action often excludes that of another; if 

 the consciousness of feeling is stronger than that of the 



1 Sir W. Hamilton, Lectures on MetapJiysics, vol. i. p. 348 ; Winslow, 

 On Obscure Diseases of the Brain and Mind, p. 437. 



