Emotion in animals specialised form of Occam's razor used in ethology, in which he stated: Charles Darwin initially planned to include a chapter on emotion in "The Descent of Man" but as his ideas progressed they expanded into a book, "The Expression of the Emotions in Man and Animals". Darwin proposed that emotions are adaptive and serve a communicative and motivational function, and he stated three principles that are useful in understanding emotional expression: First, "The Principle of Serviceable Habits" takes a Lamarckian stance by suggesting that emotional expressions that are useful will be passed on to the offspring. Second, "The Principle of
The Expression of the Emotions in Man and Animals with "ill-temper", sulkiness and determination), Chapter 10 on hatred and anger, Chapter 11 on "disdain, contempt, disgust, guilt, pride, helplessness, patience and affirmation" and Chapter 12 on "surprise, astonishment, fear and horror". In his discussion of the emotion of disgust, Darwin notes its close links with the sense of smell, and conjectures an association with excretory products. In Chapter 13, Darwin discusses complex emotional states including self-attention, shame, shyness, modesty and blushing. Darwin describes blushing as "the most peculiar and most human of the expressions". Darwin closes the book with Chapter 14 in which he recapitulates his main argument: he