CHAPTER VIII 



Instinct 



Instincts Comparable with Habits, but Different in Their Origin — Instincts 

 Graduated — Aphides and Ants — Instincts Variable — Domestic Instincts, 

 Their Origin — Natural Instincts of the Cuckoo, Molothrus, Ostrich and 

 Parasitic Bees — Slave-making Ants — Hive-Bee, its Cell-making Instinct 

 — Changes of Instinct and Structure not Necessarily Simultaneous — 

 Difficulties of the Theory of the Natural Selection of Instincts — Neuter 

 or Sterile Insects — Summary. 



Many instincts are so wonderful that their development will 

 probably appear to the reader a difficulty sufficient to overthrow 

 my whole theory. I may here premise, that I have nothing to do 

 with the origin of the mental powers, any more than I have with 

 that of life itself. We are concerned only with the diversities of 

 instinct and of the other mental faculties in animals of the same 

 class. 



I will not attempt any definition of instinct. It would be easy 

 to show that several distinct mental actions are commonly em- 

 braced by this term; but every one understands what is meant, 

 when it is said that instinct impels the cuckoo to migrate and to 

 lay her eggs in other birds' nests. An action, which we ourselves 

 require experience to enable us to perform, when performed by 

 an animal, more especially by a very young one, without ex- 

 perience, and when performed by many individuals in the same 

 way, without their knowing for what purpose it is performed, is 

 usually said to be instinctive. But I could show that none of these 

 characters are universal. A little dose of judgment or reason, as 

 Pierre Huber expresses it, often comes into play, even with ani- 

 mals low in the scale of nature. 



Frederick Cuvier and several of the older metaphysicians have 

 compared instinct with habit. This comparison gives, I think, an 

 accurate notion of the frame of mind under which an instinctive 

 action is performed, but not necessarily of its origin. How uncon- 

 sciously many habitual actions are performed, indeed not rarely 

 in direct opposition to our conscious will! yet they may be modi- 

 fied by the will or reason. Habits easily become associate with 



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