Preliminary Definitions and Illustrations. 1 7 



restricted acceptation of the term we adopted at the outset, 

 inherited. It is the result of individual acquisition, and is 

 stereotyped by repetition in the course of the experience of 

 the organism which exhibits the habit in question. Now, 

 it is well known that there is a divergence of opinion 

 among biologists as to the answer to be given to the 

 question : Are acquired characters inherited ? For us 

 this question takes the following form : Are acquired 

 habits inherited in the form of congenital instincts ? I 

 shall not, at this stage of our inquiries, express any 

 opinion in the matter. That must come after a careful 

 consideration of the evidence. But it is clearly essential 

 that we should so define the terms "habit" and 

 " instinct," and the terms " congenital " and " acquired," 

 as not in any way to forejudge the question ; nay, rather, 

 in such a way as to facilitate a due grasping of the real 

 nature of the question at issue. 



"Habit" has already been defined; it involves indi- 

 vidual acquisition. An animal does not come into the 

 world with any tendency to perform ready-made habits. 

 The expression " ready-made habits " is indeed contradic- 

 tory, for habits are reached by repetition in the course of 

 experience. If they were ready-made, they would not be 

 called habits ; if they were habits, they could not be ready- 

 made. The definition of the term " instinct " is occupying 

 our attention at present, and we have just said that what 

 is instinctive is characterized by a certain amount of 

 definiteness which is hereditary, and not acquired in the 

 course of individual experience. Instinctive performances 

 are ready-made activities, if the expression be permissible. 

 In other words, they are congenital. Let us, then, use the 



I terms "congenital " and " acquired" in such a way as to 

 be so far as possible mutually exclusive. An activity that 

 is congenital is one the definite performance of which is 



