“He was, I take it, the most perfect reasoning and observing machine that the world has seen, but as a lover he would have placed himself in a false position. He never spoke of the softer passions, save with a gibe and a sneer.”

This passage is taken from the collection’s first story and sets up expectations about Holmes. The detective is described by his best friend and associate, Dr. Watson, as someone who values logic and reason above all and perceives emotions as a weakness. What is more, according to Watson, Holmes does not experience feelings such as love, which leads to the comparison with a “machine.” 

“‘Quite so’, he answered, lighting a cigarette, and throwing himself down into an armchair. ‘You see, but you do not observe. The distinction is clear. For example, you have frequently seen the steps which lead up from the hall to this room.’”

This quote is one of Holmes’s famous pronouncements, contrasting the acts of seeing and observing. While seeing is something most people do daily, it is an involuntary function requiring no thought. Observing and noticing things, which then leads to deduction, is more difficult. According to Holmes, observing can be learned, and Watson demonstrates his observation skills later in the book by recalling various details he has noticed. However, unlike the detective, his friend is yet to make the logical connection between the details he sees and what they imply. In this way, Watson, a representative of the reading audience, can come close to what Holmes does but never quite reaches that level of reasoning skill.