MEMORY INDISPENSABLE TO. DISCOVERT. 63 



only those conjunctions of ideas which represent the cor- 

 responding conjunctions of objects, attributes, and rela- 

 tions in the external world, the mind becomes a truthful 

 image of nature. This constitutes a large part of the 

 process of education. 



It is necessary not only to acquire and store scientific 

 ideas, but also to remember and recognise them. It 

 would not be of much use for us to store our minds with 

 thoughts, if, when we require to use them, we had to wait 

 for their reappearance ; nor would it be a much more per- 

 fect arrangement if we could recall but could not recog- 

 nise them. We recall and recognise ideas by means of an 

 action of memory. Without memory there could be no 

 mental development or education ; if we had not memory, 

 our other mental powers would be nearly useless. It sup- 

 plies us largely with the material for thought and reflec- 

 tion. When Faraday's memory failed him, he was unable 

 to make any more discoveries. Memory is cohesion of 

 mental states ; it is by means of it that we are enabled to 

 reproduce past ideas and conscious mental states, and to 

 recognise them as such. Locke says memory is the power 

 which the mind has 'to revive perceptions which it once 

 had, with this additional perception annexed to them, 

 that it has had them before.' If we could only reproduce 

 our original feelings and ideas, but not recognise them as 

 prior experiences, our previous life would appear a blank, 

 and we could not identify ourselves with ourselves from 

 time to time. On memory therefore depends the con- 

 sciousness of personal identity, and largely also our power 

 of identifying present things with their existence in the 

 past. Memory is internal perception, and is that opera- 

 tion of internal perception which is not directly caused 

 by external circumstances ; all perception is really internal, 

 but may be excited either by external or internal causes. 



