v MR. DARWIN'S CRITICS 153 



amount of the former would constitute the most 

 rudimentary condition of the latter, though sen- 

 sations supply the conditions for the existence of 

 ' thought ' or ' knowledge' " (p. 67). 



This proposition is true, or not, according to the 

 sense in which the word " thought " is employed. 

 Thought is not uncommonly used in a sense co- 

 extensive with consciousness, and, especially, with 

 those states of consciousness we call memory. If I 

 recall the impression made by a colour or an odour, 

 and distinctly remember blueness or muskiness, I 

 may say with perfect propriety that I " think of " 

 blue or musk ; and, so long as the thought lasts, 

 it is simply a faint reproduction of the state of 

 consciousness to which I gave the name in question, 

 when it first became known to me as a sensation. 



Now, if that faint reproduction of a sensation, 

 which we call the memory of it, is properly termed 

 a thought, it seems to me to be a somewhat forced 

 proceeding to draw a hard and fast line of demar- 

 cation between thoughts and sensations. If sen- 

 sations are not rudimentary thoughts, it may be 

 said that some thoughts are rudimentary sensations. 

 No amount of sound constitutes an echo, but for 

 all that no one would pretend that an echo is some- 

 thing of totally different nature from a sound. 

 Again, nothing can be looser, or more inaccurate, 

 than the assertion that " sensations supply the 

 conditions for the existence of thought or know- 

 ledge." If this implies that sensations supply the 



