1 6 Information Storage and Neural Control 



the equivocation of the system, then it is possilole to encode the cor- 

 rection data so as to send it over this channel and correct all but 

 an arbitrarily small fraction of the errors. This is not possible 

 if the channel capacity is less than the equivocation. 



Roughly then, the equivocation may be considered as the 

 amount of additional information that must be supplied per 

 second at the receiving point to correct the received message. 



CONCLUDING REMARKS 



This paper has dealt primarily with some of the basic aspects 

 of the statistical theory of information. Very few comments have 

 been made regarding semantic information, not because this sub- 

 ject is unimportant, but rather because there is at present no 

 sound quantitative theory for treating semantic information. In 

 concluding, however, I would like to remark that statistical infor- 

 mation theory has relevance to semantics insofar as it tells us what 

 confidence we can place in the accuracy of the information we re- 

 ceive as opposed to the information sent. The significance or value 

 of the information to the recipient does not fall within the domain 

 of the quantitative measures provided by information theory. 



With reference to the theme of this symposium, one might say 

 that information theory provides insight for analyzing and im- 

 proving storage and communication processes, but does not unravel 

 the bewildering complexities associated with significance, meaning, 

 or value judgments. From my personal experience with the prob- 

 lems of physiological signal analysis, this fact lies at the core of 

 the difliculties which the life sciences face in applying information 

 theory to their problems. Finding significant factors in a maze 

 of statistical information is an immensely challenging problem in 

 medicine as well as in many other fields. The problems require 

 both an intelligent application of information theory and a 

 thorough knowledge of the phenomena being studied so that good 

 questions can be asked in the right way to enhance the probability 

 of getting a useful answer. 



REFERENCES 



1. Bell, D. A.: Information Theory and Its Engineering Applications. New 

 York, Sir Isaac Pitman and Sons, Ltd., 1956. 



