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 and a "geologizing expedition" – but actually spent some of his time re-exploring the old haunts of his undergraduate days. On the day of the coronation, 28 June 1838, Darwin was in Edinburgh. A few weeks later, he opened a private notebook with philosophical and psychological speculation – the "M Notebook" – and, over the next three months, filled it with his thoughts about possible interactions of hereditary factors with the mental and behavioural aspects of life.It should also be noted that Darwin made his first attempt at autobiography in August 1838. The critical importance of the "M Notebook" has