334 METHODOLOGY OF SCIENCE 



thing is repeated in life. But to express such a judgment we must 

 be in position to compare different experiences with each other, and 

 this possibility rests upon a fundamental phenomenon of our con- 

 sciousness, memory. Memory alone enables us to put various ex- 

 periences in relation to each other, so that the question as to their 

 likeness or difference can be asked. 



We find the simpler relations here in the inner experiences. A 

 certain thought, such as twice two is four, I can bring up in my 

 consciousness as often as I wish, and in addition to the content of 

 the thought I experience the further consciousness that I have 

 already had this thought before, that it is familiar to me. 



A similar but somewhat more complex phenomenon appears in 

 the experiences in which the outer world takes part. After I have 

 eaten an apple, I can repeat the experience in two ways. First, as 

 an inner experience, I can remember that I have eaten the apple 

 and by an effort of my will I can re-create in myself, although with 

 diminished strength and intensity, a part of the former experience 

 the part which belonged to my inner world. Another part, the 

 sense impression which belonged to that experience, I cannot re-create 

 by an effort of my will, but I must again eat an apple in order to 

 have a similar experience of this sort. This is a complete repetition 

 of the experience to which the external world also contributes. 

 Such a repetition does not depend altogether on my own powers, 

 for it is necessary that I have an apple, that is, that certain condi- 

 tions which are independent of me and belong to the outer world 

 be fulfilled. 



Whether the outer world takes part in the repetition of an experi- 

 ence or not has no influence upon the possibility of the content of 

 consciousness which we call memory. From this it follows that this 

 content depends upon the inner experience alone, and that we 

 remember an external event only by means of its inner constituents. 

 The mere repetition of corresponding sense impressions is not suffi- 

 cient for this, for we can see the same person repeatedly without 

 recognizing him, if the inner accompanying phenomena were so 

 insignificant, as a result of lack of interest, that their repetition 

 does not produce the content of consciousness known as memory. 

 If we see him quite frequently, the frequent repetition of the exter- 

 nal impression finally causes the memory of the corresponding inner 

 experience. 



From this it results that for the " memory "-reaction a certain 

 intensity of the inner experience is necessary. This threshold can be 

 attained either at once or by continued repetition. The repetitions 

 are the more effective the more rapidly they follow each other. 

 From this we may conclude that the memory-value of an experience, 

 or its capacity for calling forth the " memory "-reaction by repetition, 



