5r- — 



PREFACE 



Many workers in the biological sciences — physiologists, psycholo- 

 gists, sociologists — are interested in cybernetics and would like to 

 apply its methods and techniques to their own speciality. Many 

 have, however, been prevented from taking up the subject by an 

 impression that its use must be preceded by a long study of elec- 

 tronics and advanced pure mathematics; for they have formed the 

 impression that cybernetics and these subjects are inseparable. 



The author is convinced, however, that this impression is false. 

 The basic ideas of cybernetics can be treated without reference to 

 electronics, and they are fundamentally simple; so although advanced 

 techniques may be necessary for advanced applications, a great deal 

 can be done, especially in the biological sciences, by the use of quite 

 simple techniques, provided they are used with a clear and deep 

 understanding of the principles involved. It is the author's belief 

 that if the subject is founded in the common-place and well under- 

 stood, and is then built up carefully, step by step, there is no reason 

 why the worker with only elementary mathematical knowledge 

 should not achieve a complete understanding of its basic principles. 

 With such an understanding he will then be able to see exactly what 

 further techniques he will have to learn if he is to proceed further; 

 and, what is particularly useful, he will be able to see what techniques 

 he can safely ignore as being irrelevant to his purpose. 



The book is intended to provide such an introduction. It starts 

 from common-place and well-understood concepts, and proceeds, 

 step by step, to show how these concepts can be made exact, and 

 how they can be developed until they lead into such subjects as 

 feedback, stability, regulation, ultrastability, information, coding, 

 noise, and other cybernetic topics. Throughout the book no 

 knowledge of mathematics is required beyond elementary algebra; 

 in particular, the arguments nowhere depend on the calculus (the 

 few references to it can be ignored without harm, for they are 

 intended only to show how the calculus joins on to the subjects 

 discussed, if it should be used). The illustrations and examples are 

 mostly taken from the biological, rather than the physical, sciences. 

 Its overlap with Design for a Brain is small, so that the two books are 

 almost independent. They are, however, intimately related, and 

 are best treated as complementary; each will help to illuminate 

 the other. 



