Intuition is the subtle balance between observation and deduction

The essence of scientific method is the combination of observation and deduction.1 However, there is a subtle third skill of maintaining an appropriate balance between the two. Whereas observation and deduction can be taught, this third skill - let us call it intuition - can not be reduced to a series of principles. The core of science is art. However, one can learn certain guidelines which will increase the probability of acquiring this skill.

Doing science is like following a recipe for hippopotamus pie, which begins First, you catch a hippopotamus. After you have caught your hippopotamus - that is, decided on your hypothesis - then you can follow the steps of research methods much as you can follow the instructions in a recipe. However, there are no clear principles for discovering that tentative theory, called a hypothesis, which makes sense of the facts. However, certain guidelines increase the probability of doing so. You are more likely to catch a hippopotamus if you know their habits and hang around their habitats.

Intuition is not some mystical property that some fortunate people magically acquire. It is the result of considerable experience. When describing intuition, one is tempted to use the metaphor of smell. One sniffs a rat on encountering a significant clue and one smells a red herring on encountering a misleading clue. Chapter 1: Observation focused on the modality of sight. However, it is important to remember that observation requires all sensory modalities. You will remember that I acquired important clues by smelling the lips of the corpse in one case [STUD] and by identifying a perfume in another [HOUN]. Toby, the mutt with an educated nose, helped us follow trails in a couple of cases [STUD, SIGN]. Our species has lost much of the power of this sense by getting uppity - that is, by standing on our hind legs, we remove ourselves from the source of smells. You will note, however, how often Watson described me as lying on the ground in search of clues. Smell is a very primitive sense with its receptors in the old brain. It is not surprising, then, that it is linked to intuition, which is apparently mysterious only because we are out of touch with it. It is embedded in our unconscious rather than our conscious minds. Perhaps it is not surprising then that detectives are often said to be "nosy".2

1   The late Victorian era, as represented so well by Sherlock Holmes, was probably the last time we had full confidence in objective science. Since then, Heisenberg's Uncertainty Principle has demonstrated a limitation of observation and Godel's Incompleteness Theorem has demonstrated a limitation of reason. Confidence in the technology which emerged from objective science has also waned. It received a major blow at 10:40 p.m. on 12 April 1912, when the iceberg (representing nature) sunk the Titanic (representing science-and-technology). Soon after, the technology-enhanced slaughter of the First World War (1914-1918) led many people to question the value of science and technology.

2   Researchers are also often described as "nosy". My mother once asked me what I was doing. I grandiosely replied that I was trying to understand how the universe worked. She put me back in my place by saying: Ah, ye're just nosy!